#eevblog - 2021-05-09 - AustNet Archive Project

// #eevblog — 2021-05-09

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« 2021-05-08 2021-05-10 »
04:53 <EEVBot> [Twitter] - eevblog - Just a reminder that whatever your office backdrop looks like for your Zoom calls, it sucks compared to Wernher von… https://t.co/Bk53uM1AJa
05:15 <Lemon> hey electrohead
05:39 <Lemon> I draw a schematic (well, I took various examples from datasheet) for a precision current source, can I send you it to see if its correct ? :>
06:41 Join: Tezzers ([email protected]) to #EEVblog
08:46 Quit: Tezzers_ ([email protected]) Ping timeout: 121 seconds
30:12 * electrohead waves at Lemon
30:20 <Lemon> :O
31:00 <electrohead> I can take a look, but be warned - I haven't ever designed or built a current source, so I possibly won't be of much help
31:06 <electrohead> T3sl4 and arch come to mind
31:47 <rust_collector> if I was to make one, you would end up with a retro-source, not a current one
32:10 <Lemon> haha ho well, its mostly about the opamp part that buffer the vref, im not sure
33:13 <Lemon> https://imgur.com/a/95aHIbs
33:13 <EEVBot> [Title] - Imgur: The magic of the Internet
33:14 <electrohead> rust_collector: lol
33:14 <Lemon> here it is
34:36 <Lemon> I took various examples from datasheets, and tried to put it together
40:58 <electrohead> your handwriting is as bad as mine XD
41:37 <Lemon> ye true xd
41:40 <Lemon> I did my best !
41:53 <rust_collector> yeah, just... damn you pretty writing people
42:02 <Lemon> I even used a ruler heh
42:54 <electrohead> are you german?
43:49 <Lemon> nope, french :>
44:03 <electrohead> oh ok :)
44:10 <electrohead> I can definitely tell european
44:51 <electrohead> OPAL77 - is that the correct marking on the one op amp?
45:03 <Lemon> opa 277
45:04 <rust_collector> 277?
45:14 <Lemon> ho rusty I bought dis https://www.leboncoin.fr/bricolage/1929963815.htm
45:15 <EEVBot> [Title] - leboncoin.fr
45:17 <rust_collector> OI learn to read
45:20 <Lemon> 35 delivered, brand new
45:26 <Lemon> instead of 60 on amazon
45:30 <electrohead> ahh ok, thanks :p
45:40 <rust_collector> ok, that is done, now get the crimpers for 13
45:56 <Lemon> nahhhh
46:05 <Lemon> buuut as a handheld for the clamp, I found this https://www.leboncoin.fr/bricolage/1975682387.htm?ac=206978287
46:05 <EEVBot> [Title] - leboncoin.fr
46:13 <Lemon> case is rough but who cares
46:24 <Lemon> its pretty well made, still sold around 170 euros
48:05 <Lemon> https://docs.rs-online.com/f599/0900766b800a5dde.pdf
48:46 <rust_collector> so, you are stuck looking at chevraux arnold devices now?
49:08 <Lemon> nah its just easy to find here it seems
49:46 <Lemon> 1% accuracy or better, I guess thats fine for measuring the hot water heater, or stuff like that
49:51 <Lemon> I have the big bois if I want digits
50:02 <rust_collector> yeah, and you don't want that
50:21 <Lemon> I want something sturdy and protected
50:25 <Lemon> it fits this
50:35 <Lemon> and for 30 euros, maybe 35-37 delivered...
50:42 <Lemon> its dirty but thats fine, I can clean it
51:08 <electrohead> Lemon: for the opa277, you may need a resistor between pins -In and output, would have to play around with it
51:22 <Lemon> haaa for the bias current ? I thought of it !
51:34 <Lemon> or bias voltage, I forgot
54:05 <electrohead> bias current (cancellation)
54:23 <electrohead> but, be warned, I'm going off the datasheet, and I haven't made anything around this at all
54:25 <electrohead> lol
55:36 <electrohead> "A resistor added to cancel input bias current
55:39 <electrohead> errors may actually increase offset voltage and noise."
55:51 <electrohead> so, just play with it; maybe simulate it?
57:17 <Lemon> I will try yes, well on ltspice the lm399ah isnt there
57:20 <Lemon> which is annoying
57:28 <Lemon> and I struggle anyway with it
57:54 <rust_collector> someone must have made a model for that?
00:07 <electrohead> https://ez.analog.com/voltage-references/f/q-a/119221/lm399ah/355623#355623
00:10 <EEVBot> [Title] - LM399AH - Q&A - Voltage References - EngineerZone
01:06 <Lemon> hmmm ok I will try to simulate it
01:11 <Lemon> thanks for taking a look :>
01:21 <Lemon> I thikn the voltage ref/adjustable voltage part is pretty fine
01:34 <Lemon> I want 6 ranges, 100ma down to 1ua
10:59 <Lemon> https://www.leboncoin.fr/outillage_materiaux_2nd_oeuvre/1472617983.htm?ac=206978287 those look cute
11:00 <EEVBot> [Title] - leboncoin.fr
13:07 <electrohead> https://0xznc01.pw:2600/public/IMG_20210508_110619.jpg
13:08 <electrohead> \o/
14:15 <Lemon> heh hot hot
17:00 <electrohead> I can't wait to grab the habanero peppers
17:01 <electrohead> :D
17:11 <electrohead> oh, hey, ever use this? https://github.com/Qucs/qucs
17:13 <EEVBot> [Title] - GitHub - Qucs/qucs: Qucs Project official mirror
17:21 <electrohead> I got looking around at stuff, and came across that
17:46 <Lemon> no, what is it ?
21:33 <Lemon> https://www.leboncoin.fr/outillage_materiaux_2nd_oeuvre/1086449623.htm?ac=206978287
21:35 <EEVBot> [Title] - leboncoin.fr
21:36 <Lemon> I quite like this one
21:45 <Lemon> its a 3.5 digits, but quite accurate with low ranges
21:52 <Lemon> it looks funny
22:23 <electrohead> I can't view those pages
22:45 <electrohead> the captcha is not working
23:18 <Lemon> a captcha ? thats weird
23:29 <Lemon> its a philips pm 2513
04:17 <Lemon> what sucks is that the ac clamp I bought got shrouded connectors
04:30 <Lemon> as opposed to regular banana jacks on the philips
12:54 Quit: alfbaz ([email protected]) Quit: leaving
17:35 Join: alfbaz ([email protected]) to #EEVblog
19:23 <Kuschelpony> all i got is
19:25 <Kuschelpony> Voltmètre digital
19:25 <Kuschelpony> Multimètre numérique
19:25 <Kuschelpony> PHILIPS PM 2513
19:25 <Kuschelpony> Digital multimeter
19:25 <Kuschelpony> Paiement sécurisé avec
19:26 <Kuschelpony> Votre argent est conservé et le vendeur est payé lorsque vous confirmez la bonne réception du colis.
19:28 <Kuschelpony> Plus d’informations sur le paiement sécurisé
19:36 <Kuschelpony> so that site is weird
25:10 <Lemon> hmmm yeah weird
25:19 <Lemon> besides that its a nice dmm for 30 delivered
25:29 <Lemon> 3.5 digits but it got low ranges, like 100nA
29:47 <Lemon> I also found a multimetrix dm220 for 55 delivered, in perfect shape with test leads
32:38 Quit: Dantali0n ([email protected]) Quit: Bye
17:04 <T3sl4> Lemon: i'm not sure you know how to wire an op-amp :P
38:08 Join: Dantali0n ([email protected]) to #EEVblog
44:45 <Lemon> maybe, maybe xd
45:01 <Lemon> I never experimented with them, so im just trying my bbest by observing examples, looking at videos :>
54:36 <DHess_US> And ... eevblog down, because why not.
56:03 <Ysjoelfir> I agree. at least for the OPA277, the LT1001 looks about right (didn't check the pinout though)
56:42 <Ysjoelfir> I know what you wanted to do with the 277, Lemon, but check again what you draw there :)
57:05 <Ysjoelfir> drew?
57:10 <Ysjoelfir> drawed?
57:14 <Ysjoelfir> I think drew
57:16 <Ysjoelfir> whatever
59:24 <Lemon> yes im not sure about pin 6 !
59:32 <Lemon> is that the wrong part ?
02:38 <Ysjoelfir> so... what would happen if the OPA277 wants to drive... lets say 5 volts? (also, why do you grab VCC for that thing from the 10 volts?)
09:03 <Lemon> from what I understand, this opamp is here to buffer the vref, and avoid any drop in voltage from the load, but I wasnt sure on how to wire it, im watching a video on opamps again to understand, im a bit lost :>
13:13 <Ysjoelfir> assume you have 5V on the output of the OPA277. write 5V on that pin 6. then look what else is connected to pin 6.
17:56 <Lemon> ha yes there is also 10v
18:02 <Lemon> if I understand right
18:30 <Ampera> https://cdn.discordapp.com/attachments/270440074477436928/840653783364665374/20210508_024243.jpg
18:58 <Lemon> as we take the output from the previous opamp to link it to the inverting output, and then to ground
24:14 <Ysjoelfir> huh? no, there is no 10V
32:04 <Lemon> ok lets scratch the last part, im going to try and understand the vref, since the beginning :>
32:32 <Lemon> I know that it upscale the 6.95v of the ref to 10V and buffer it, but im mixing all inputs.outputs of the opamp
32:41 <Lemon> and why there is those resistors etc
32:44 <Lemon> its confusing
35:09 <Ysjoelfir> ok ok ok. you go to fast :D going back to the basics is good, BUT: lets first understand what the problem with the 277 is.
35:53 <Ysjoelfir> Immagine you have 5V on pin 6 of the 277. follow the line, connected to pin 6 of the 277, and check everything that is connected to it.
36:27 <Lemon> there is pin 4 of the previous opa
36:42 <Lemon> and what is it ?
36:45 <Lemon> I dont understand those two pins
36:57 <Lemon> I understand that the opamp willdo everything to keep the two input voltage equal
37:04 <Lemon> but what are those 7 and 4 pins for ?
37:16 Join: arch ([email protected]) to #EEVblog
37:39 <Ysjoelfir> supply voltage?
40:20 <T3sl4> Ampera: are you suggesting Lemon solve his problem with 240V?
40:41 <Lemon> yes but why do I see those pins not connected on some circuit ?
40:53 <Lemon> thats because the opamp is used as a comparator only ?
41:34 <Lemon> and what those pins got in common with the rest, like if I apply 10v, or 15 or 20
41:45 <Lemon> what is changing ? at other pins ?
41:46 <Ysjoelfir> no, it NEEDS a supply voltage, ALWAYS. its often not drawn because its obvious for the knowledgeable person that it has to be connected. often its drawn somewhere at the side
41:58 <Lemon> ok !
43:05 <Ysjoelfir> so. ignore pins 4 and 7 for now. on both of those. we deal with those later.
43:33 <Ysjoelfir> now, check again what I asked you to do at 20:35 :)
44:57 <Lemon> there is the negative output of the vref
45:28 <Lemon> and a link from the lt1001 output going to the inverting input, and to our node
45:42 <Lemon> but I dont understand those two resistors, from the output of the lt1001
45:58 <Ysjoelfir> I do not completely agree with the term "negative output", but ok, lets ignore that naming discussion for now. for now.
46:09 <arch> T3sl4, you remember that AOZ1073 fly-buck i made earlier? i swapped the 10uH coupled inductor for 4.7uH (like the datasheet recommends), and the transient response is much better. one last mystery left is the, what i think, is subharmonic oscillation: https://imgur.com/a/pEOQKUN
46:10 <EEVBot> [Title] - Imgur: The magic of the Internet
46:24 <Ysjoelfir> the link from the LT1001 you mean is NOT the output. its the INVERTING input.
46:28 <arch> the last screenshot
46:48 <arch> 2A transient on top of 1A static load
46:51 <T3sl4> yey
46:55 <Ysjoelfir> I see some clipping there, arch! :P
47:06 <arch> Ysjoelfir, that is because i zoomed into the capture
47:19 <Ysjoelfir> shame on you! (I thought so ;) )
47:20 <Lemon> I meant, before that
47:25 <Lemon> its coming from its output, no ?
47:40 <Lemon> it comes from pin 6, to a 9k resistor, then stops by the inverting input, and continues
48:16 <Ysjoelfir> ah. yes. ok. than you were right, but lets also ignore that part for the moment, Lemon
48:21 <Ysjoelfir> next?
48:35 <Ysjoelfir> whats also on this pin 6 that is outputting 5V in our example?
49:16 <Lemon> thats it ? well there is the negative supply of the heater part of the vref, is that it ?
49:26 <Ysjoelfir> yes
49:43 <Ysjoelfir> what would happen, if you put +5V there
49:52 <Ysjoelfir> where you drew the GND symbol
50:44 <Lemon> nothing? I dont understand :>
50:50 <Ysjoelfir> In german we have this nice saying. "Plus auf Masse, das knallt klasse!" - basically translates to "Plus to ground, that makes a nice bang!"
50:52 <Lemon> I mean, thats the negative part of the supply
51:17 <Lemon> a short ?
51:21 <Ysjoelfir> so.. what happenes if you put a lead from +12V of a car battery to the ground terminal of a car battery?
51:28 <Lemon> yeah it shorts it
51:40 <Ysjoelfir> yes! exactly. You build a nice magic smoke generator there :D
51:45 <Kuschelpony> Rot ist blau und Plus ist Minus
51:52 <Kuschelpony> Wähler Steht, Gestell dreht
52:01 <Lemon> so I tried to take the 10v on the ground lane
52:03 <Ysjoelfir> Hach, die schoenen alten Sprueche :P
52:07 <Kuschelpony> blaue lampe leucht, Beamter entfleucht
52:10 <Lemon> to feed the inverting input of the opa277
52:11 <Ysjoelfir> xD
52:13 <Lemon> is that the error ?
52:27 <Ysjoelfir> no, you just connected a driving source directly to ground.
52:50 <Lemon> ha yes but I wanted 10v on that inverting input
52:52 <Ysjoelfir> you can't* connect an opamp output to ground.
52:56 <Lemon> but right now its connected to ground
53:03 <Lemon> ok !
53:10 <Lemon> so, now I dont understand that part
53:16 <Lemon> there is the 10v output, from the lt1001
53:20 <Kuschelpony> Ysjoelfir, die drei Teiel gehören fest zusammen, das ist ein Spruch aus der Frühzeit der Telefonvermittlungen
53:42 <Lemon> what is supposed to be connected to that input ? of the opa277
53:45 <Kuschelpony> aber die zwei letzten Teile sind verloren gegangen weil schon lange keienr mehr die Hintergründe kennt
53:55 <Ysjoelfir> Ich sollte mein Wissen in dieser Zeit wohl etwas auffrischen :D
54:03 <Lemon> on the example, it was "com" of the reference
54:05 <Lemon> so negative
54:13 <Lemon> thats why I took it here
54:20 <Ysjoelfir> which input, Lemon?
54:28 <Lemon> output sorry output
54:30 <Lemon> not input
54:49 <Ysjoelfir> ok. so the question is: where do you connect the output of the 277?
55:02 <Ysjoelfir> *your question is
55:07 <Lemon> yes :>
55:15 <Lemon> it feels its in wrong way
55:36 <Lemon> its supposed to do everything to make it 10v on its inputs
55:38 <Kuschelpony> efor these who did not understand german, we telked about really ancient telephone exchanges
56:57 <Ysjoelfir> ok. Judged by that question I would suggest we go in babysteps from the ref to the load and see what parts you are missing, Lemon :) First we start with the 399. please explain how the combination R1 / LM399 (the part between pin 1 and 2) works.
57:13 <Kuschelpony> Da gabs so einiges was scheif gehen konnte, wenn die Hebdrehwähler alle wegen Steuerfehler feststehen mußte man die einzeln von Hand lösen (wähler steht) und keinesfalls einen elektrischen Reset machen weil das sonst das gestell aus der Verankerung gerissen hätte oder gleich ins nächste Stockwerk runtergehämmert
57:21 <Lemon> yes thats why I wanted to go back there, I dont understand
57:27 <Lemon> you feed it 15v, ok
57:28 <Kuschelpony> blaue lampe war Hauptfehler, in der ganzen Stadt geht nichts
57:35 <Lemon> 6.95v get out pin 1
57:48 <Lemon> it goes to non inverting input of lt1001
57:54 <Lemon> but, it also goes to a 7.5k resistor
58:00 <Lemon> back to the 15v input
58:22 <Lemon> or no
58:30 <Lemon> the 15v input goes to the 7,5k resistor
58:39 <Lemon> I dont understand :(
59:16 <Ysjoelfir> Oh. Ok, so ergibts sinn :D Danke fuer die Erklaerung, Kuschelpony :) Muss ich mal meine Mutter, Postbeamte in Pension, fragen, ob sie das noch kennt. WAr zwar etwas vor ihrer Zeit, aber sie kennt solche Dinge eigentlich :)
59:41 <Ysjoelfir> Lemon: BABYSTEPS! XD Not seven mile jumps. lets start here: what is between pins 1 and 2 of the LM£99?
59:41 <steve30> i have a headache
59:53 <Kuschelpony> greetings from someone who enjoys to read the old books
59:53 <Lemon> the zener ref :>
59:59 <Lemon> positive/negative
00:02 <Ysjoelfir> awwww steve30 :(
00:05 * Ysjoelfir pets the steve
00:15 <Ysjoelfir> Kuschelpony, will do :)
00:51 <Ysjoelfir> Lemon: right. so, what does a zener do if you feed it a voltage over its zener voltage with no resistor in between the source and the zener?
02:30 <Ampera> T3sl4, no it's just a neat plug
03:29 <Lemon> it wont conduct ?
03:50 <Ysjoelfir> lets say.... quite the opposite.
03:52 <Lemon> ok lemme watchs omething on zener diode
03:56 <Lemon> yes thats what I just thought
04:01 <Lemon> im tired, and saying shit
04:24 <Ysjoelfir> heh :D if you want we can go through the circuit and correct it tomorrow when you are not tired?
06:14 <Lemon> nonono
06:19 <Lemon> I want to understand, NOW
06:21 <Lemon> so ok
06:32 <Lemon> we have 15v, which is over the breakdown voltage of the diode
06:36 <Lemon> is it right ?
06:45 <Lemon> so if we have no resistor, theres no current flowing
06:45 <Ysjoelfir> we are right, yes
06:50 <Ysjoelfir> erm, no
06:55 <Ysjoelfir> thats not right now.
06:59 <Lemon> whyyyy
07:06 <Lemon> the diode act as a load ?
07:11 <Ysjoelfir> what happenes to a zener if you pass its breakdown voltage?
07:17 <Lemon> it conducts ?
07:21 <Ysjoelfir> to its internal resistance, lets call it that way
07:22 <Ysjoelfir> yes
07:25 <Ysjoelfir> exactly
07:25 <Lemon> ha yes ok
07:28 <Lemon> so its a load
07:29 <Lemon> in some sort
07:38 <Ysjoelfir> lets call it basically a short
07:42 <Lemon> yeah
07:59 <Lemon> does it have a low internal resistance ?
08:01 <Ysjoelfir> so now whe have the situation: 15V - diode with something like 1 ohms or whatever - ground.
08:09 <Lemon> ok
08:12 <Ysjoelfir> what would happen with the diode?
08:19 <Lemon> it burns
08:25 <Ysjoelfir> right
08:27 <Lemon> because it probably cant handle that
08:32 <Lemon> this delicate piece of shit
08:46 <Lemon> so we put a resistor to limit current
09:43 <Ysjoelfir> kind of. in the datasheet of a zener you usually have some information about the zener current. you want to chose the resistor that way, that this current fits, for optimal stability
09:53 <Lemon> ok !
10:05 <Lemon> so 2mA
10:10 <Lemon> according to the circuit
10:14 <Lemon> they say 5% resistor
10:26 <Lemon> ok ok then
11:00 <Ysjoelfir> so. we calculate the resistor
11:47 <Ysjoelfir> the formula for this is: R = (Vcc - Vzener) / (Izener + Iload)
12:35 <Ysjoelfir> with Vcc = the voltage over the R and the Zener and Iload = the current NOT flowing through the zener, but through the resistor
12:58 <Ysjoelfir> (=basically everything that goes into whatever is loading the zener, hence the name)
15:11 <Lemon> so
15:13 <Lemon> hmmmm
15:27 <Lemon> i dont understand your second sentence
15:31 <Lemon> according to your formula
15:37 <Lemon> thats 15v-6.95v
16:12 <Lemon> divided by (1 ohm for the zener so 15?) + Iload (I dont know)
16:34 <Lemon> Iload is also 15 ?
16:38 <Ysjoelfir> eh?
16:40 <Ysjoelfir> I
16:41 <Ysjoelfir> current
16:43 <Ysjoelfir> not resistance
16:47 <Lemon> yes
16:51 <Lemon> 15v, into 1ohm
16:57 <Lemon> thats 15 amp ?
17:04 <Lemon> if without any resistor
17:12 <Ysjoelfir> [21:09:43] <Ysjoelfir> kind of. in the datasheet of a zener you usually have some information about the zener current. you want to chose the resistor that way, that this current fits, for optimal stability
17:12 <Ysjoelfir> [21:09:52] <Lemon> ok !
17:13 <Ysjoelfir> [21:10:05] so 2mA
17:13 <Lemon> we have only the zener, which got 1ohm internal resistor
17:29 <Lemon> yes but I calculated that knowing we need a 7.5k ohm resistor
17:39 <Lemon> and you ask me how to figure out the resistor :>
17:43 <Ysjoelfir> so... then take a look at the datasheet?
17:55 <Lemon> but for what ? im confused
18:02 <Lemon> I know the Vcc and Vzener
18:04 <Ysjoelfir> to find out the zener current....?
18:12 <Ysjoelfir> https://www.analog.com/media/en/technical-documentation/data-sheets/199399fc.pdf
18:19 <Lemon> well its supposed to be over 0.5 and under 10ma
18:21 <Lemon> okkkk
18:27 <Lemon> thats what you mean by Izener
18:31 <Lemon> idk why I thought about something else
19:41 <Lemon> I dont understand Iload
19:56 Quit: arch ([email protected]) Connection closed
19:57 <Ysjoelfir> ok, let me draw a snippet from your circuit. one sec
24:06 <Ysjoelfir> https://drive.google.com/file/d/13ONONnx3tT_tChT40ld8XD53FPFHQCLq/view?usp=sharing
24:07 <EEVBot> [Title] - 302 Moved
24:43 <Lemon> ok thanks
24:54 <Lemon> but I dont understand better xd how to get that Iload if you dont know that resistor ?
25:22 <Ysjoelfir> you know what voltage will be on the + input of the op, right?
25:37 <Lemon> 6.95v ?
25:41 <Ysjoelfir> right.
26:07 <Ysjoelfir> so. how can you calculate a current you don't know, having a voltage and something other?
26:41 <Lemon> we need the resistance ?
27:01 <Ysjoelfir> exactly. or basically some value that determines how much current goes into that op.
27:16 <Lemon> but we are trying to know this resistance
27:19 <Lemon> thats why I dont understand
27:50 <Ysjoelfir> we want to know Iload. not Iges
28:02 <Lemon> but to have Iload, we need a voltage and a resistance
28:05 <Lemon> and we want that resistance
28:08 <Lemon> but for that resistance we need Iload
28:53 <Ysjoelfir> I load = U[Opam_noninverting_input] / R[Opamp_noninverting_input]?
30:03 <Lemon> so 6.95
30:20 <Lemon> no wait
30:28 <Lemon> yes, 6.95 ?
30:33 <Ysjoelfir> correct
30:34 <Lemon> im confused, like fuck
30:36 <Lemon> ok
30:41 <Lemon> and 9k ?
30:45 <Lemon> nono
30:48 <Lemon> no not 9k
30:51 <Lemon> wtf im saying
31:21 <Lemon> 1ohm ?
31:23 <Lemon> I have no idea dude
31:26 <Lemon> literally no idea
31:43 <Ysjoelfir> https://www.analog.com/media/en/technical-documentation/data-sheets/LT1001.pdf
31:52 <Lemon> how im supposed to know the resistance of the non invertin g input
32:04 <Ysjoelfir> by taking a look into the datasheet...? :D
32:18 <Lemon> haaaa I was trying to guess it :(
32:26 <Lemon> I thought there was something obvious in the circuit I missed
32:33 <Lemon> so 100M ohm, typical ?
32:41 <Lemon> input resistance differential mode
33:23 <Lemon> no it makes no sense
33:30 <Lemon> but thats the only value I can find
34:37 <Ysjoelfir> yes, but you would want the worst case scenario. also: you could either calculate it, which is in case of opamps just a better guessing as they can fluctuate quite a bit, or just keep in mind that there is a value for the current going into an opamps input.
34:55 <Ysjoelfir> its also in the datasheet, if thats not obvious ;)
35:35 * rust_collector just put the Lemon spec pizza in the incinerator
36:45 <Lemon> input bias current ?
36:51 <Lemon> 2nA ?
37:32 Quit: Kuschelpony ([email protected]) Connection closed
37:32 <Ysjoelfir> yes.
38:14 <Lemon> so if I got the current, to get resistance I need a voltage
38:24 <Ysjoelfir> no.
38:38 <Ysjoelfir> you wanted this current. nothing else.
38:56 <Ysjoelfir> you already have Izener from the datasheet of the zener, and now you have Iload from the opamp.
38:58 <Lemon> [21:28:53] <Ysjoelfir> I load = U[Opam_noninverting_input] / R[Opamp_noninverting_input]?
39:08 <Ysjoelfir> you just got I load...
39:09 <Lemon> you told me, to find that R of non inverting input
39:18 <Lemon> hmmmm
39:19 <Lemon> ok
39:51 <Ysjoelfir> to be precise, I told you that you COULD calculate Iload, OR (21:34) just read in the datasheet the input bias current ;)
40:09 <Lemon> so 15-6.95/0.002+0.000000002 ?
40:17 * electrohead bops in
40:26 <rust_collector> bop bop!
40:31 <Ysjoelfir> rememberL our initial plan was that: [21:11:00] <Ysjoelfir> so. we calculate the resistor
40:31 <Ysjoelfir> [21:11:47] the formula for this is: R = (Vcc - Vzener) / (Izener + Iload)
40:31 <Ysjoelfir> [21:12:35] with Vcc = the voltage over the R and the Zener and Iload = the current NOT flowing through the zener, but through the resistor
40:31 <Ysjoelfir> [21:12:58] (=basically everything that goes into whatever is loading the zener, hence the name)
40:40 <Ysjoelfir> yes, exactly Lemon :)
40:52 <Ysjoelfir> hi mr. beerhead :)
41:01 <electrohead> lol, hey man :P
41:04 <electrohead> I have tomorrow off \o/
41:11 <Lemon> I found 4K
41:37 <Lemon> they chose 7.5K
41:38 <Lemon> WHY
41:41 <Ysjoelfir> good :)
41:46 <Ysjoelfir> well... you answered it yourself
42:31 <Lemon> hmmm
42:35 <Ysjoelfir> [21:18:18] <Lemon> well its supposed to be over 0.5 and under 10ma
42:47 <Lemon> so they just took a different value ?
42:49 <Lemon> between that and that
42:56 <Ysjoelfir> you chose 2mA. they chose something different
42:59 <Ysjoelfir> yes.
43:02 <Lemon> and why do they chose 2ma or something
43:06 <Lemon> they do tests ?
43:23 <rust_collector> maybe they just did, and it worked?
43:27 <Ysjoelfir> yes.
43:33 <Lemon> ok, so we have that resistor
43:36 <Lemon> NOW WHAT
43:52 <rust_collector> pizza
44:01 <Ysjoelfir> now you have the first part, the reference voltage creation, understood. At least I hope.
44:35 <Lemon> well not totally to be honest
44:40 <Lemon> its confusing me
45:13 <Lemon> pin 1, of lm 399
45:15 <Lemon> so the diode
45:37 <Lemon> its an input ?
45:41 <Lemon> well, its considered as one
45:50 <Lemon> but why the diode is drawn that way
45:53 <Lemon> thats confusing me
45:58 <Ysjoelfir> well.... it kind of is.
46:04 <Ysjoelfir> why is that confusing you?
46:23 <Ysjoelfir> thats the way zeners work, isn't it? or are you watching some strange way to draw it?
46:28 <Lemon> because the good ol 6.95v everybody wants is on pin 2, right ?
46:36 <Ysjoelfir> eh? no?
46:42 <Lemon> thats what I dont understand
47:09 <Lemon> we go from 15v, to that 7.5k resistor
47:12 <Lemon> to that pin 1
47:13 <Lemon> ok ?
47:19 <Ysjoelfir> yes?
47:38 <Lemon> so a curent flow in that direction into the diode
47:44 <Ysjoelfir> yes
47:57 <Lemon> how can it go in that way, and also output 6.95 ?
48:01 <Lemon> thats what I dont understand
48:07 <Lemon> either I missed something really obvious
48:07 <Ysjoelfir> it doesn't output anything?
48:11 <Lemon> or I looka at it the wrong way maybe
48:17 <Ysjoelfir> yes. probably both.
48:18 <Ysjoelfir> first
48:35 <Ysjoelfir> a zener doesn't output a voltage, it DROPS a voltage
48:46 <Lemon> so it acts as a regulator
48:50 <Lemon> somehow
49:04 <Ysjoelfir> second, that thing is realy JUST a zener. NOT any active circuit.
49:05 <Lemon> if input voltage is higher than breakdown voltage
49:15 <Ysjoelfir> its not a regulator, no.
50:59 <Lemon> https://imgur.com/ut0CBG0
50:59 <EEVBot> [Title] - Imgur: The magic of the Internet
51:04 <Lemon> thats what I dont understand
51:06 <Lemon> in that circuit
51:13 <Lemon> in what way current flow ?
51:26 <Lemon> because it looks like we input something and it outputs it in the same point
51:46 <Lemon> thats why I said "its outputing by pin2 ?"
54:29 <Lemon> ok nvm, I looked at a video and I think I understand now
54:33 <Lemon> but that still feels weird
54:39 <Ysjoelfir> thats not the way how electricity works :D electricity doesn't know anything about inputs and outputs. its all about potentials. the current flows from 15V through the resistor through the diode to ground. while doing that it the diodes drops 6.95 volts, the resistor drops the remaining voltage.
55:05 <Lemon> yes ok ok !
55:09 <Lemon> I get it now I think xd
55:11 <Lemon> jesus h christ
55:21 <Lemon> drugs really did damages
56:02 <Lemon> so for the lt1001
56:14 <Lemon> we got 6.95v going to his non inverting input
56:18 <Ysjoelfir> stop
56:55 <Lemon> ok
57:11 <Ysjoelfir> babysteps again :D You now look only at: LT1001, R3, R2 and what goes into the noninverting input of the opamp, your ~7V
58:10 <Ysjoelfir> for that, immagine OPA277 isn't there, as is the load and R4-9
58:36 <Lemon> yes yes
58:42 <Lemon> only the lt1001 part with the vref
58:51 <Ysjoelfir> so. what configuration do we have there?
59:02 <Lemon> thats the part I dont understand
59:14 <Lemon> I know that inputs of an opamp are always equal
59:21 <Lemon> that curent never flow through them
59:40 <Lemon> well infact I've been lied too it seems, as I saw that 2nA value somewhere :>
59:59 <Ysjoelfir> nop[e,. you haven't :)
00:12 <Ysjoelfir> you now just got to know a very very important thing
02:14 <Lemon> yes ? tell me tell me
02:18 <Ysjoelfir> reality
02:32 <Lemon> yeah it struck hard a couple times already
03:06 <Ysjoelfir> ;)
04:16 <rust_collector> *thud*
04:21 <Ysjoelfir> XD
04:32 <Ysjoelfir> so, Lemon. What opamp configuration do we have there?
04:59 <Lemon> well I still don't know, thats still something I want to know :>
05:27 <Ysjoelfir> https://en.wikibooks.org/wiki/Electronics/Electronics_Formulas/Op_Amp_Configurations
05:29 <EEVBot> [Title] - Electronics/Electronics Formulas/Op Amp Configurations - Wikibooks, open books for an open world
06:25 <Lemon> a non inverting amplifier ?
08:01 <Lemon> suspens is too intense
08:05 <Lemon> but I think it is
08:13 <Lemon> as we amplify the diode voltage to 10v
08:22 <rust_collector> does the output follow anything?
08:23 <Lemon> and we feed the diode voltage to the non inverting input
09:00 <Lemon> thats the part I dont fully understand
09:04 <Lemon> it looks like a voltage divider
09:10 <Lemon> with r3 and r2
09:17 <Lemon> inverting input being between the two
10:18 <Ampera> https://cdn.discordapp.com/attachments/310478241989263371/840681498255425536/20210508_153533.jpg
10:49 <Lemon> stoner plugs
15:03 <Ysjoelfir> lol, indeed :D Ampera, less drugs for your plugs!
15:35 <Ysjoelfir> and Lemon: yes, correct. its a noninverting amp.
15:41 Join: bdunh ([email protected]) to #EEVblog
15:42 <rust_collector> Imo, they look like someone gave them a Lemon, and said it was a nice sweet orange
15:49 <Ysjoelfir> lol :D
17:08 <Lemon> so, where do we go now :>
17:18 <Lemon> we know its a non inverting amp
17:29 <rust_collector> no, you think you know that
17:36 <Ysjoelfir> do you want to take a look a a description vid or whatever for the noninverting opamp, or do you want to wait until I am done fooding for me to explain? (could take some time)
17:38 <Lemon> I dont understand the part where it monitors the other input etc
17:49 <Lemon> I will look at one :>
17:54 <Lemon> I already disturb you enough !
19:51 <rust_collector> Lemon in your drawing, there is no resistor between the input side, and the output side, just a wire?
34:30 <Ysjoelfir> Lemon, its fine, I will just need more time to answer :)
34:53 <Lemon> all good, im watching a video and trying to figure it out :>
35:16 <Lemon> then we'll discover together that I didnt understand a thing
35:18 <Lemon> Xd
42:24 <Lemon> ok so I think I understand most of it
42:31 <rust_collector> most of what?
42:36 <Lemon> but if I use the values used in the examples I found in datasheet
42:41 <Lemon> I find 10.077V
42:48 <Lemon> that isnt 10V to me
42:55 <Ysjoelfir> perfect!
43:13 <Lemon> those two resistors are for the gain
43:19 <Lemon> but why 10.077 ?
43:22 <Lemon> it makes no sense
43:23 <Ysjoelfir> you found this stupid thing called "reality" again!
43:30 <Lemon> we need a trimmable resistor ?
43:50 <Ysjoelfir> USUALLY those schematics look a bit more like.... wait, I draw.
44:04 <Lemon> I guess a trimmable resistor is the thing to have
44:10 <Lemon> like instead of the 9k one
44:13 <Lemon> or 20k doesnt matter
45:12 <Ysjoelfir> no.
45:17 <Lemon> hmmmm
45:23 <Ysjoelfir> trimmers have a freakishly shitty tempco
45:37 <Lemon> so you need the precise value directly ?
45:52 <Lemon> but thats weird, in my lm399ah based ref I have, there is a trimpot
45:56 <Ysjoelfir> no, you don't
45:58 <Lemon> actually in any dmm you have a trimpot
46:01 <Lemon> but but
46:02 <Ysjoelfir> NO opamp is perfect
46:08 <Ysjoelfir> NO 399 is perfect
46:12 <Ysjoelfir> NO resistor is perfect
46:13 <Lemon> yeah I know that
46:16 <Ysjoelfir> NO trace is perfect
46:18 <Lemon> thats why trimpot are nice no ?
46:21 <Lemon> so you can offset it
46:47 <Ysjoelfir> A dmm is ually way less acurate than what you intend to build with a LM399.
47:11 <Ysjoelfir> https://drive.google.com/file/d/13gQSoS9jKdeGYbfU2ZXqBTqnSvW1Y2sX/view?usp=sharing
47:11 <EEVBot> [Title] - 302 Moved
47:16 <Ysjoelfir> usually you have something like that
47:17 <Lemon> well yes for current if its trimmed perfectly thats true
47:44 <Lemon> hmmmm
47:48 <Lemon> to find the perfect value ?
47:54 <Lemon> but I swear, in the ref I have theres a trimpot
47:57 <Lemon> and its super stable
48:24 <Ysjoelfir> did you heat it up?
48:44 <Ysjoelfir> grab a hairdryer and blast that thing. now check again for stability
48:53 <Lemon> I monitored it over some temp changes yeah
49:10 <Lemon> but yeah ofc it needs a decently stable temperature, but over 3C it didnt shift by 100ppm
49:15 <Lemon> I think it was like 2-3 ?
50:18 <Ysjoelfir> thats indeed pretty good. what ref was that?
51:21 <Lemon> erf its dipped in red resin
51:27 <Lemon> and I dont really want to remove it tbh
51:34 <Lemon> im trying to find one online
52:02 <Lemon> but if I can achieve 0.01%, im already happy
52:03 <Ysjoelfir> I thought you bought that thing? :D you should know what you have there?
52:15 <Lemon> ha you meant the Vref or the trimpot ?
52:23 <Lemon> the trimpot idk but the ref is a lm399h
52:29 <Lemon> it was on ebay
52:35 <Lemon> and it wasnt said
52:39 <rust_collector> you people are confusing me. stop that
52:45 <Lemon> nothing looks incredible on it, smd resistors etc
52:53 <Lemon> probably 0.1 or better
52:58 <Lemon> but no ultra low tempco stuff
53:06 <Ysjoelfir> the whole reference circuit I meant. take a pic.
53:10 <Lemon> haaaaa
53:12 <Lemon> ok sec
53:15 <Ysjoelfir> rust_collector: I am sorry, I stop now
53:54 <rust_collector> I wonder if it is just me, or do you skip around between different things?
53:54 <Lemon> ha its still for sale and we can see the trimpot ! https://www.ebay.fr/itm/254927388007?hash=item3b5adb3d67:g:RtsAAOSwPA1cOaqw
55:34 <Ysjoelfir> ah. thats a pretty well known thing. in that circuit the trimmer is not contributing much to the tempco. this is the circuit diagram (which I still find VERY strangely drawn) https://www.circuitvalley.com/2018/11/diy-open-source-lm399-V2-voltage-reference-10v-dmm-calibrate.html
55:35 <EEVBot> [Title] - Embedded Engineering : DIY Open Source LM399 10V Voltage Reference, Second Revision
56:10 <Ysjoelfir> rust_collector well... the big topic is lemon trying to learn that putting 5V to ground is not a good idea ;P
57:21 <rust_collector> well, as I read it, you asked what sort of opamp configuration it was, he looks at a video, and says it is 10.077v?
58:02 <Lemon> yeah it was to say that I mostly understood
58:03 <Ysjoelfir> its about this circuit from Lemon https://imgur.com/a/95aHIbs :) I was asking for the LT1001 part.
58:12 <Lemon> that those two resistors are for gain etc
58:24 <Lemon> so in his circuit he's indeed paralleling resistors as you said
58:31 <Lemon> and you said that trimpot isnt contributing much to tempco
58:33 <Lemon> why that ?
59:04 <rust_collector> oh, I thought you were on the 277 part.
59:34 <Ysjoelfir> naaah, that is the interesting part, rust_collector ^^ we get to that later.
59:42 <Lemon> ok so whats next ? :>
00:18 <rust_collector> more pizza
01:05 <Ysjoelfir> Lemon well... from the pic I see that its a 1k trimmer. also its in series to the 20k resistor. USUALLY the trimmer will be in the range of a few ohms. if it has a tempco of 200ppm/K, how much change will there be if its like... 10 ohms with 200ppm of a total value of 20010 ohms?
02:14 <Lemon> 20mR per K, so yeah not a lot ?
02:58 <Ysjoelfir> yep. so for your 3K change it will change from eg. 20010 ohms to 20010.06 ohms.
03:21 <Lemon> thats clever
03:31 <Lemon> so a trimpot is indeed the solution ! :P well, in part
05:19 <Lemon> so we could put a trimpot in series with the 20k resistor ?
05:23 <Lemon> if its a small value
05:26 <Lemon> it could work ?
06:24 <Ysjoelfir> yes. but you should still ad the trimming resistor positions in parallel to the normal resistors. just don't populate them.
07:26 <Lemon> hmmm I dont get it by "just dont populate them"
07:38 <Lemon> haaaa ok
07:38 <Lemon> I see
07:45 <Lemon> so I have spots if I need them
07:50 <Ysjoelfir> yes
07:52 <Lemon> okok
08:01 <Lemon> so from all of this
08:08 <Lemon> I can at least see another error
08:12 <Lemon> on the opa277
08:22 <Lemon> I took vcc from the 10v output, which is wrong
08:41 <Lemon> I need to take it from the 15v
08:42 <Ysjoelfir> thats very right
09:15 <Lemon> and to pin 6
09:25 <Lemon> I need 10v
09:31 <Lemon> so pin 6 to 6 ?
09:33 <Lemon> hmmmm
09:37 <Lemon> no
09:40 <Lemon> yes
09:45 <Lemon> yes as I want it to stay 10v
09:53 <Ysjoelfir> no.....
09:57 <Ysjoelfir> what
09:58 <Ysjoelfir> would
09:59 <Ysjoelfir> happen
10:14 <Ysjoelfir> if you put +12V of a car battery to GND?
10:51 <Lemon> a short, but how is that a short ?
10:58 <Ysjoelfir> babysteps, lemon, dammit! :D you are going 20 steps ahead again! there are still other mistakes in this before we go to the 277
11:24 <Ysjoelfir> you put pin 4 of the LM399 to GND? pin 6 of the 277 si connected to pin 4 of the 399 and thus connected to GND?
12:03 <Lemon> ha yes but as I said I need to change that !
12:14 <Lemon> connect pin 6 of lt1001 to pin 6 of opa277
13:05 <Ysjoelfir> ok. then: redo the circuit (ignore the LM317 part for now) with what we have now and ignore the freakin' 277!
14:55 <Lemon> https://imgur.com/vXqG8va
14:56 <EEVBot> [Title] - Imgur: The magic of the Internet
15:27 <Lemon> I didnt add the trimpot but it doesnt matter for now
15:35 <Lemon> brb a sec
18:40 <Lemon> ok
20:25 <Lemon> I got confused because of the ref102 example
20:32 <Lemon> which is taking "com" to the output of the opa
21:15 <Ysjoelfir> show the example, please.
23:07 <Lemon> https://imgur.com/kxpxz7y
23:08 <EEVBot> [Title] - Imgur: The magic of the Internet
25:16 <Ysjoelfir> so. for what reason do they do that?
27:17 <Lemon> to buffer the 10v ref ? so when you load it, it doesnt drop ?
31:16 <Ysjoelfir> no.
31:56 <Ysjoelfir> how could it buffer that? the output is pointing away from the load, isn't it?
33:36 <Lemon> thats what I dont understand
33:49 <Lemon> I mean, why would we use a opamp here ?
33:57 <Lemon> if its not to make it stay 10v no matter the load ?
34:01 <Lemon> but its the wrong way
34:04 <Lemon> thats confusing me
37:04 <Ysjoelfir> what happenes if the load drops some voltage?
38:01 <electrohead> 3
38:05 <Ysjoelfir> correct!
38:24 <electrohead> lol, my terminal was slowing up, and I fat fingered that
38:26 <electrohead> my bad :P
38:29 <electrohead> and, hey o/
38:38 <Lemon> hmmm
38:55 <electrohead> I'll balance my answer out by replying -3
38:58 <electrohead> :p
39:03 <Ysjoelfir> oh nice!
39:19 <Ysjoelfir> also, hi mr. beerhead :D
39:24 <electrohead> :D
39:29 <electrohead> Lemon: how far did you get?
39:34 <electrohead> sorry I wasn't much help earlier
39:44 <Lemon> the opa will do everything to equal its non inverting input to the inverting one ?
39:54 <electrohead> I've mucked with op amps, but haven't dove into the math part of things, much
40:19 <Lemon> heh thats ok :>
40:23 <Ysjoelfir> we basically have the 10V reference part sorted out.
40:31 <DHess_US> The ref102 forces 10 volts between pins 6 and 4, but there is considerable current at pin 4, which the voltage follower provides. Since then 10 volts is across R, and nothing flows into the non-inverting input, the constant voltage across R makes a constant current.
41:06 <Lemon> heh I was about to say that !
41:19 <DHess_US> It is also possible to reverse the operational amplifier to also make a current source, but it would be floating with the load from the output to inverting input.
41:34 <DHess_US> That is a common configuration to drive analog meters.
42:11 <DHess_US> Or it is used to drive a voltage reference with a constant current and provide a buffered output at the same time.
42:35 <Lemon> when you say there is considerable current at pin 4, which the voltage follower provides.
42:41 <Lemon> can you explain it please ?
43:51 <DHess_US> How to turn a shunt reference into a series reference, https://www.circuitstoday.com/wp-content/uploads/2008/08/positive-reference-voltage-generator.JPG
44:31 <Lemon> well you know im at the part where im learning every single aspect step by step xd
44:57 <DHess_US> The ref102 has a quiescent operating current from the input pin to common.
45:11 <DHess_US> Because it is a series reference.
46:12 <Lemon> but its very small no ?
46:29 <Lemon> I think I saw it in the datasheet
46:43 <DHess_US> If you look at the link I just made, converting a shunt reference (zener) into a series reference means that there are three pins, power, output, and ground.
46:53 <Lemon> 1.4ma
47:04 <DHess_US> The ground pin also carries the negative supply voltage to the operational amplifier so that gets added to the ground pin.
47:10 <Lemon> yes I looked at it but as I said, I lack basics
47:15 <Lemon> so for now, its kinda chinese for me
47:37 <Lemon> Ysjoelfir is explaining to me the examples I found from datasheet from A to Z :>
47:54 <DHess_US> Some references have their operating quiescent current go out their output pin instead of common pin.
48:12 <rust_collector> from d to å
48:12 <DHess_US> Those are "floating" references.
09:21 <hsn> Hey T3sl4
09:26 <hsn> I found a joke
10:05 <hsn> https://photos.app.goo.gl/S2dJBRokjBZzojXd6
10:41 <T3sl4> i've seen indians do it for less
13:56 <rust_collector> hsn this is a special for you: https://bit.ly/3tx1WSc
13:57 <EEVBot> [Title] - Bitly
22:11 <hsn> T3sl4: the guy wants it for his phd
42:13 <Ysjoelfir> so, Lemon, can we continue?
42:21 <Lemon> ha yes ofc !
42:25 <Lemon> im waiting you :>
42:42 <Ysjoelfir> So I assume by now you found out what the opamp is for?
42:54 <Lemon> ha no, I was waiting you :P
43:02 <Ysjoelfir> pffffff
43:04 <Lemon> I prefer an explaination, I understand better like that
43:10 <Ysjoelfir> rust_collector, why didn't you tell him?
43:34 <Lemon> [23:39:44] <Lemon> the opa will do everything to equal its non inverting input to the inverting one ?
43:46 <rust_collector> because it is dumb to teach him the wrong stuff?
45:43 <rust_collector> and... I am busy eating local cheese, melted onto lasagna
46:48 <hsn> rust_collector: r u doing butly to hide the title?
47:11 <rust_collector> maybe?
47:22 <Lemon> Ysjoelfir is it correct ?
47:24 <hsn> And i have to eat pastas
48:23 <rust_collector> me too
48:54 <Ysjoelfir> uuuh, rusty, is it.. erm... the... ost thats also on the grandiosa?
49:06 <rust_collector> it is one of those, yes
49:30 <rust_collector> jarlsberg. the area here is called nord-jarlsberg.
49:34 <Lemon> the suspense is too intense
49:38 <Lemon> I need to know Ysjoelfir xd
49:38 <Ysjoelfir> Lemon, ok. so. the thing you said is not wrong, but it won;t help us in this case. I think. let me see if I can explain it easy with that in mind
49:47 <Lemon> ok :>
50:32 <Ysjoelfir> rust_collector ah yes, thats the one I had in mind :) I actually wanted to try that by itself. like, without grandiosa under it. but I didn't find any in the kiwi.
50:37 <Ysjoelfir> Lemon:
51:18 <Ysjoelfir> well, ok, it can help. but we need to add one thing to keep in mind here.
52:43 <Ysjoelfir> you see, an opamp has those two inputs, the inverting and the noninverting one, right?
53:39 <Lemon> yes
53:49 <Ysjoelfir> you know what those are for?
54:09 <Lemon> explain to me since the beginning, so I see if I know or not :>
54:18 <Lemon> because I tend to confuse myself xd
54:19 <Ysjoelfir> ok.
54:40 * Ysjoelfir hides from T3sl4 and everyone else for simplifying a lot now
54:43 <Ysjoelfir> so
54:49 <rust_collector> one time in 1937, the engineer, let s call him bob.....
54:53 <Ysjoelfir> lol
55:00 <Ysjoelfir> not that far from the beginning :P
56:15 <Ysjoelfir> ooook. so. you have your idea of the opamp trying to keep both inputs identical.
56:47 <Ysjoelfir> now. you use an opamp usually with some kind of feedback. like, feeding some part of the output back to one of these inputs
58:24 <Lemon> to monitor it in some sort ?
59:38 <Ysjoelfir> yes, you could say that. because as it tries to keep its inputs the same it needs SOME way to do that, right? so it has to have some connection from the output to the input. now, if you feed it back to the inverting input this bit will be subtracted from the output. if you feed it back to the NONinverting input it will be added to the output signal.
00:23 <Ysjoelfir> for example lets take a look at the LT1001 circuit
01:03 <Lemon> okkkkkkk
02:04 <Ysjoelfir> you give it ~7V at its noninverting input. we assume now that the feedback is just a short instead of the two resistors, ok?
02:16 <Lemon> ok !
03:38 <Ysjoelfir> so before anything has happened we have the following situation: the opamp is sitting there, waiting for something to do. it has "nothing" on its output.
03:46 Join: reg7805_ ([email protected]) to #EEVblog
04:22 <Lemon> because it needs a voltage on the inverting input ?
05:13 <Ysjoelfir> well, we assume its waiting for something to do. so like.... + = 0V. so it outputs 0V, tries to make the -, which is connected to the output, identical to that, which... is achieved in that moment, right?
06:08 <Lemon> hmmm
06:11 Quit: Reg7805 ([email protected]) Ping timeout: 121 seconds
06:19 Nick: reg7805_ is now known as Reg7805
06:44 <Lemon> you have 7 on noninverting input
06:47 <Lemon> 0 on inverting
07:02 <Ysjoelfir> nonono, not yet!
07:06 <Lemon> ha ok!
07:15 <Lemon> because it would equal it in that situation
07:20 <Lemon> if I understood correctly
07:22 <Ysjoelfir> we start with 0 on the + input
07:28 <Lemon> ok
07:35 <Lemon> se we have 0 everywhere
07:41 <Ysjoelfir> exactly
07:58 <Ysjoelfir> ok. NOW we give it those 7V to its noninverting input. now it has a problem: the inverting input is still 0V from the previous situation, so it somehow has to modify that to make it identical to the signal on the noninverting input. what would it do?
08:41 <Lemon> thats where you need a feedback from the output ?
09:06 <Ysjoelfir> yes. remember, our assumed situation is: 7V on +, - connected to out.
09:28 <Lemon> so at that moment
10:02 <Lemon> as we know that if out is connected to inverting input, it will be substracted
10:45 <Lemon> right ?
11:13 <Ysjoelfir> yes. exactly. and it wants to achieve that the result of its "calculation" is 0, which would mean that its inputs are identical, right?
11:59 <Lemon> no because + got 7v ?
12:33 <Ysjoelfir> I think you misread. I wrote: it WANTS to achieve.... :)
12:42 <Lemon> ha yes sorry
12:43 <Lemon> ok
13:03 <Lemon> soooo yes idealy they would be 0 ?
13:08 <Lemon> hmmm
14:55 <Ysjoelfir> right now we have + = 7V, - = 0V. so we have as a calculation: +7V + (-0V) = +7V. which is not 0, so the opamp tries to correct that
15:37 <Lemon> ok
15:43 <Lemon> so what happen next ?
16:38 <Ysjoelfir> the opamp ramps up its output voltage. lets say it "tries" it with 1V on its output. what would happen?
17:55 <Lemon> hmmmm
18:04 <Lemon> its not enough so it ramps it again ?
18:29 <rust_collector> yep
18:32 <Lemon> because we have + 7 + (-1)
18:56 <Lemon> so it ramps it till he got 7v ?
18:57 <Ysjoelfir> yes. it would have 7V on the noninverting and 1 on the inverting input. so it would "calculate": +7V + (-1V) = 6V. still not zero.
19:01 <Ysjoelfir> exactly
19:30 <Lemon> thats a simple concept yet quite confusing at first
19:56 <Ysjoelfir> yes, you have to get it, but then it becomes pretty simple actually
20:17 <Lemon> yeah I will need some time :> so for our lt1001
20:22 <Lemon> there is a voltage divider, right ?
20:24 <Ysjoelfir> so. now we make it A BIT more complicated.
20:32 <Ysjoelfir> yes, exactly that is the bit I was refering to
21:04 <Ysjoelfir> so if it outputs 7V it would not get those 7 volts to its input, but only a part of that
21:10 <Ysjoelfir> so it needs to go higher
21:33 <Lemon> haaa okkk so it uses gain
21:37 <Lemon> as said in the video I saw
21:57 <Lemon> and to calculate the gain you do 9/20+1
22:03 <Lemon> if I remember right
22:26 <Ysjoelfir> exactly. but now you (should) understand how this gain works, or better, how those two resistors can make it output some specific voltage.
23:21 <Lemon> lets say im close to understand it lol
23:27 <Lemon> so we have 7 on +
24:33 <bdunh> What's going on with the forum??
24:33 <Lemon> im really tired but lets try
25:02 <Lemon> a part of the output is fed back to -
25:19 <rust_collector> Lemon do you have an opamp?
25:32 <Lemon> which is Vout(1+r3/r2), right ?
25:34 <Lemon> no sadly
26:07 <rust_collector> aww
26:38 <rust_collector> bdunh they are probably trying to fix it until it stops working
26:58 <Lemon> hmmm im lost again
27:05 <Lemon> on how it multiplies the voltage
27:34 <rust_collector> it has external power right? on 4 and 7, or what it was?
27:42 <Ysjoelfir> vout is Vin(1+Rf/Rgnd)
28:34 <Lemon> Rf and Rgnd being what in our case ?
28:39 <Lemon> the two resistors in the divider ?
28:43 <rust_collector> yes
29:10 <Lemon> so we have 3.22V on Vout
29:15 <Ysjoelfir> rf is the feedback resistor (the one going from output to inverting input), rgnd is the one foing from the inverting input to gnd
29:27 <Lemon> ok ! so 3.2
29:30 <Lemon> if im right
29:41 <Lemon> so it feeds back that voltage
29:47 <Lemon> but its not equal to 7
29:52 <rust_collector> right
29:54 <Lemon> so it ramps it up
30:02 <Lemon> wait
30:04 <Lemon> hmmm
30:07 <rust_collector> yes
30:11 <rust_collector> go on
30:40 <Lemon> it ramps it up till its 7 ? but no it makes no sense
31:06 <rust_collector> that is what they do... the inputs wants to be equal
31:15 <Lemon> yes but we want 10V in our case
31:19 <rust_collector> yes
31:51 <Lemon> I dont get it, how we get 10V
31:54 <Lemon> because if its 3.2
31:57 <Ysjoelfir> 7x(1+(9/20)) = ? :)
32:18 <Lemon> yeah I know that but
32:21 <Lemon> hmmm
32:30 <Lemon> I want to know what happens in the right order
32:34 <Lemon> its 7 at the +
32:37 <Lemon> output tied to 0
32:38 <Lemon> -
32:54 <Lemon> by the little divider we get 3.2 on output
33:03 <Lemon> so inverting is 3.2 too right ? at that stage
33:11 <Lemon> it want to equalize noninverting output
33:13 <Ysjoelfir> no.
33:26 <Lemon> ok thats what I dont understand
33:34 <Ysjoelfir> not quite sure how you get to 3.2V?
33:48 <Ysjoelfir> [01:31:57] <Ysjoelfir> 7x(1+(9/20)) = ? :) <----- thats pretty much 10 volts
34:11 <Lemon> but with the previous equation
34:18 <Lemon> [01:27:42] <Ysjoelfir> vout is Vin(1+Rf/Rgnd)
34:34 <Lemon> so 15 x (1+20/9)
34:36 <Ysjoelfir> thats... exactly the equation I wrote down there
34:48 <Ysjoelfir> huh? where do you get that 15 from
34:53 <Ysjoelfir> also, RF is not 20k
34:53 <Lemon> Vin is noninverting input ?
35:00 <Lemon> haaa
35:02 <Lemon> yes I reverted them
35:03 <rust_collector> not the power, the input
35:08 <Lemon> ok I was taking Vcc
35:11 <Lemon> im really tired
36:00 <Lemon> but ok, I get it now :>
36:02 <Lemon> I get it
36:07 <Lemon> after all those years
36:50 <Ysjoelfir> \o/
36:57 <rust_collector> ok, so are you ready to repeat that tomorrow?
37:37 * electrohead hands Lemon a congratulatory beer
37:57 <Lemon> but its not finished !
38:01 <Lemon> but I take it, thanks xd
38:07 <electrohead> there are many beers to hand out :P
38:11 <Lemon> now we have the opa277 :>
38:16 <Lemon> if I understood right
38:28 <Lemon> we feed it 10V on noninverting output
38:53 <Ysjoelfir> no we don't
38:57 <rust_collector> that one is opposite to the 1001, and turned 90 degrees in the phases, so you can not use the same logic there
38:57 <Lemon> no ?
39:12 <Lemon> but
39:46 <rust_collector> not really, but have 3 minutes off first, before we all turn to much
39:56 <rust_collector> or mush
39:58 <Lemon> ref is outputing 10V, goes through a resistor, and goes to + ?
40:07 <Ysjoelfir> it doesn't
40:21 <Ysjoelfir> how big is the resistance of "load"?
40:40 <Lemon> the input impedance of the meter ?
40:58 <Lemon> haaaa
41:00 <Ysjoelfir> lets be correct here: the shunt resistance (or burden resistance) of the meter
41:06 <Lemon> it acts as a divider ?
41:10 <Ysjoelfir> yes.
41:13 <Lemon> between the meter and the other resistor
41:14 <Lemon> ok
41:22 <Ysjoelfir> lets assume a PERFECT meter first
41:29 <Ysjoelfir> so Rmeter = 0R
41:39 <Lemon> ok
41:52 <Ysjoelfir> what happenes?
42:53 <Lemon> well
43:00 <Lemon> we have 0v ?
43:19 <Ysjoelfir> where
44:11 <Lemon> at the noninverting input ?
44:32 <Ysjoelfir> right. so that results in?
45:08 <Lemon> Vout = Vin so Vout = 0 ?
45:21 <Lemon> as output is tied to -
45:26 <Ysjoelfir> right. so VOut = GND
46:08 <Lemon> ok
46:16 <Lemon> so now, we enter a real confusion stage
47:30 <Lemon> I dont get why theres an opamp here now
47:37 <Lemon> lets say the load is 1ohm
47:49 <Lemon> we'll have something like 0.9V (if R = 100R)
48:05 <Lemon> so Vin = Vout, inverting input being also 0.9V
48:09 <Lemon> right ?
48:22 <Ysjoelfir> exactly
48:28 <Lemon> so whats the point ?
48:38 <Ysjoelfir> well.. this circuit is called a buffer.
48:46 <Lemon> but wheres mah 10V ?
48:51 <Lemon> :(
49:00 <rust_collector> it comes from the other opamp?
49:06 <Ysjoelfir> exactly.
49:36 <Ysjoelfir> you don't need 10 volts over the meter, do you? you want to have a precise current source, not a voltage source.
49:38 <Lemon> and goes to 100R ?
49:44 <Lemon> ha but yes
49:45 <Ysjoelfir> yes
49:46 <Lemon> jesus
49:54 <rust_collector> nah
50:04 <rust_collector> a wire
50:23 <Lemon> hmmmm
50:24 <rust_collector> jesus is too positive
50:31 <Lemon> I still dont fully understand
50:42 <Lemon> can you make me a simple explainaition of that opa277 role ?
50:48 <Lemon> like, really simple one
50:57 <Ysjoelfir> ok
51:17 <rust_collector> Used as a buffer amplifier to eliminate loading effects (e.g., connecting a device with a high source impedance to a device with a low input impedance).
51:17 <rust_collector> V out = V in {\displaystyle V_{\text{out}}=V_{\text{in}}\!\ } {\displaystyle V_{\text{out}}=V_{\text{in}}\!\ }
51:17 <rust_collector> Z in = ∞ {\displaystyle Z_{\text{in}}=\infty } {\displaystyle Z_{\text{in}}=\infty } (realistically, the differential input impedance of the op-amp itself, 1 MΩ to 1 TΩ)
51:19 <Ysjoelfir> compensating the resistance of the meter
51:35 <Lemon> yes I know it does that
51:40 <Lemon> but I dont understand how
51:51 <Lemon> and why
51:54 <Lemon> I just dont get it
52:29 <rust_collector> that was pretty mangled, sorry
52:46 <Ysjoelfir> lemon... 10V / 100R = ?
53:02 <Lemon> 100ma ?
53:15 <Ysjoelfir> right. now we add the meter in series to your 100R. 10V / 110R = ?
53:41 <Lemon> 0.090 ?
53:51 <Lemon> erm
53:52 <Lemon> 90ma
53:56 <Ysjoelfir> right.
54:21 <hsn> rust_collector: how do u see what u wrote?
54:38 <hsn> in}}\!\ } {\displaystyle V_{\text{out}}=V_{\text{in}}\!\ }
54:39 <Ysjoelfir> so by connecting your meter with 10 ohms internal resistance you get 10% error in your 100mA calibrator
54:43 <hsn> This stuff
54:49 <Lemon> yes
54:56 <Ysjoelfir> so... is that good?
55:00 <Lemon> it isnt
55:08 <hsn> Ysjoelfir: r u kidding me
55:22 <rust_collector> hsn like the part about the voltage follower here: https://en.wikibooks.org/wiki/Electronics/Electronics_Formulas/Op_Amp_Configurations
55:22 <hsn> 10% with lemon .. is enough?
55:23 <EEVBot> [Title] - Electronics/Electronics Formulas/Op Amp Configurations - Wikibooks, open books for an open world
55:40 <Ysjoelfir> so... why do we compensate the internal resistance of the meter?
55:53 <Lemon> well to avoid those errors
55:58 <Lemon> but what happen stage by stage with the opa ?
56:01 <hsn> Ur irc support latex or whatever it is ru
56:04 <hsn> rust_collector: ^
56:38 <rust_collector> nope, does not look like it
56:50 <Ysjoelfir> thats... what I wanted to explain before you asked me to make it easy :D
57:12 <Lemon> ok :>
57:16 <Lemon> I really dont get that part
57:20 <Lemon> like, what is the opa doing etc
57:25 <Lemon> I know why he's here, and what he does
57:29 <Lemon> but how he does it is a mystery
57:38 <Ysjoelfir> ok. so. lets do babysteps again :)
57:46 <hsn> Lemon .. an op amp is she .. not he
57:50 <Ysjoelfir> we already established that this is a buffer. what does a buffer do?
58:09 <Lemon> it keeps an output stable ?
58:57 <hsn> Lemon .. if u have weak voltage supply like somthing sensitive .. and u overload it .. what happens?
59:16 <Lemon> you'll destroy it
59:20 <Ysjoelfir> yes, but it does more. hint: I always like the german name for the buffer a bit more: We call it an Impedance converter.
59:33 <Ysjoelfir> which is, what hsn is trying to bring you to as well I guess ;)
59:40 <Lemon> it avoids any overloads ?
01:46 <Ysjoelfir> yes, but thats not what we want to achieve here. it won't be destroyed, but what happenes if you load a resistive divider?
02:14 <hsn> Lemon: that weak voltage source we call .. high impedance source ... If its high enough .. u cant read it with ADC of mcu .. it changes .. for example.. an electrochemical sensor usually have very high impedance ... So the solution is to bring some ideal ADC that takes 0uA current .. or (high impedance load) ..
02:59 <hsn> Or .. u can bring a buffer in middle .. the buffer will convert ur high impedance input to low impedance output ..
03:34 <Lemon> if you load it
03:36 <Ysjoelfir> ^ impedance converter :)
03:46 <Lemon> it changes the voltage ?
03:47 <hsn> Thay t op amp has very high input impedance .. hence it will almost take near 0uA current
04:01 <DHess_US> So what is the German name for impedance converter?
04:09 <Ysjoelfir> Impedanzwandler
04:18 <hsn> Wandler
04:19 <hsn> XD
04:44 <hsn> Idk why but wandler seems perfect name for dildo
04:53 <Lemon> well idk
05:02 <Lemon> I understand why its here
05:03 <rust_collector> hsn you do not know about dildos...
05:09 <Lemon> but I dont understand stage by stage what happens
05:27 <hsn> Lemon: no .. lets say u ve voltage divider ..
05:42 <Lemon> you what ?
06:01 <rust_collector> you have a voltage divider
06:03 <Ysjoelfir> you have a voltage divider
06:06 <Ysjoelfir> lol
06:07 <hsn> 10vdc ---- 100k --- 100k ---- gnd
06:08 <Lemon> ha right
06:18 <hsn> Whats the middle point ?
06:28 <hsn> In volts
06:31 <Lemon> 5v ?
06:40 <hsn> Yes
06:52 <hsn> Now .. lets imagine u want to read that 5v
06:58 <hsn> With ADC of arduino
07:12 <DHess_US> It is 5 volts, with an impedance of 50 kilohms.
07:36 <hsn> To make it simple .. lets say adc of Arduino is something like 10k resistor to gnd ..
07:53 <hsn> Now u connect that 5v to arduino .. but wait
07:56 <Lemon> you will load the circuit
08:00 <Lemon> so its not 5v anymore
08:02 <DHess_US> This is what you are missing to make your point, https://en.wikipedia.org/wiki/Th%C3%A9venin%27s_theorem
08:03 <EEVBot> [Title] - Thévenin's theorem - Wikipedia
08:05 <hsn> U just made 100k parallel with 10k
08:18 <DHess_US> hsn, no
08:27 <DHess_US> 50k in parallel with 10k.
09:22 <DHess_US> Simplify it before considering the load. With the divider, it looks like 5 volts in series with 50 kilohms.
09:37 <hsn> DHess_US: hmm yeah if u consider it 5v .. u right i should ve
09:58 <DHess_US> You don't have to do it the way I am suggesting, but it is much easier.
10:07 <Lemon> well you know what
10:12 <Lemon> at that point my brain is cider
10:15 <Lemon> if not worse
10:27 <Lemon> I barely know how to spell my name anymore
10:41 <hsn> I always make mistake in thevnin so i make it 10v --- 100k ---- (100k || 10k) ---- gnd
10:45 <rust_collector> L and tab works
10:50 <DHess_US> voltage sources have an associated series resistance. Current sources have an associated parallel resistance.
10:53 <Lemon> I will reread everything tommorow
11:16 <Lemon> because I'll make you all repeat infinitly :>
11:23 <hsn> Lemon: but that buffer is acting like 1Meg to ur circuit instead of the 10k of adc ..
11:24 <Lemon> I simply cant compute anything anymore
11:47 <Lemon> yes I understood that, but anyway
12:01 <Lemon> we'll see tommorow you already taught me enough :>
12:16 <Lemon> so thanks Ysjoelfir and everybody else, I appreciate you take the time !
12:19 <Lemon> I feel dumb sometimes
12:46 <hsn> If that makes u better i dumb also xD
13:15 <Lemon> seems not :>
13:18 <hsn> EEVBot: time DHess_US
13:19 <EEVBot> No time zone data found for DHess_US!
13:21 <Lemon> ok guys thanks again for everything
13:26 <Lemon> time to sleep, I'll continue tommorow :>
13:31 <hsn> EEVBot: time Lemon
13:32 <EEVBot> No time zone data found for Lemon!
13:32 <rust_collector> have a good nap
13:46 <hsn> Enjoys
13:52 <Lemon> see you peeps !
13:59 <rust_collector> hsn he should be the same as the rest of up here
14:05 <DHess_US> No time zone data because I am not on Earth! Dun-dun-DUN!
14:26 <rust_collector> timeless!
14:47 <hsn> EEVBot: time rust_collector
14:48 <EEVBot> It is currently 2021/05/09 02:14:47 where rust_collector resides.
15:02 <hsn> One hour difference
15:08 <hsn> https://www.instagram.com/p/COn3e5nNKVU/
15:17 * Ampera sneezes
15:30 <Ampera> what I don't get is Halcyon insisted that the bot be nicknamed "EEVBlog" when I made it
15:39 <Ampera> despite me wanting it to be EEVBot
15:56 <rust_collector> I think he wanted this one to be named that too
16:29 <Ampera> I don't get why though, everyone will just think that it's actually dave instead of just a bot
16:33 <Ampera> maybe that's funny or something
16:57 <rust_collector> I think I remember electrohead saying that, but we had a vote, and we agreed that too many though tit was dave
17:13 <hsn> I still do
17:22 <Ampera> weirdo
17:27 <rust_collector> well, you are... you
17:38 <hsn> Ampera never understood why i keep talking to the bot ..
18:02 <hsn> What he dont understand is that it confuses me with dave
18:09 <electrohead> it's officially EEVBot
18:15 <Ampera> good
18:20 <Ampera> that's what it should have been since day 1
18:25 <hsn> EEVBot: about
18:25 <EEVBot> I am EEVBot v1.1, made in python, with love, and fueled by beer. Hear me roar.
18:34 <hsn> EEVBot: roar
18:34 <EEVBot> Easter eggs make me roar. *ROAR!*
18:35 <Ampera> EEVBot Debug and Version
18:36 <EEVBot> Ampera: nega-tory, ghost rider!
18:51 <Ampera> EEVBot status
18:51 <EEVBot> Ampera: nega-tory, ghost rider!
18:57 <Halcyon> Morning all
18:59 <Ampera> >/
19:01 <hsn> EEVBot: kill yourself
19:02 <EEVBot> hsn: nega-tory, ghost rider!
19:05 <hsn> Lame
19:07 <Ampera> speak of the devil
19:08 <electrohead> lol
19:12 * electrohead pokes Halcyon
19:13 <rust_collector> EEVBot is negative
19:14 <EEVBot> rust_collector: nega-tory, ghost rider!
19:16 * Ampera attack-hugs Halcyon 
19:24 <hsn> Hola Halcyon
19:24 <Halcyon> :D
19:58 <Ampera> check signal, Halcyon
20:20 <Halcyon> Looks neat :)
20:24 <rust_collector> is he out of hair product today?
20:27 <hsn> Thanks
20:35 <Halcyon> No, I have plenty of hair product
20:37 <Ampera> rust_collector, he has enough stored in his scalp to last him a few centuries
20:40 <hsn> U look neat too
21:19 <hsn> rust_collector: what was it .. hmmm in Germany
21:35 <hsn> Su bist klug und nett
21:38 <rust_collector> I only get to see his old pictures from his school days or something
21:38 <hsn> Du bist
21:40 <rust_collector> hah, yes
21:53 <rust_collector> something like that
22:00 <Ysjoelfir> lemon, you are very welcome :) We can continue tomorrow if you want.
22:16 <Ysjoelfir> also, hi Halcyon and Ampera and whoever else joined in I might have missed :D
22:26 <Halcyon> Hey Ysjoelfir
22:32 <hsn> Gn all gn Ysjoelfir
22:42 <rust_collector> gngngn
22:48 * Ampera smacks Ysjoelfir with 100ft of 4 conductor 6AWG cable
23:08 <hsn> EEVBot: convert 6awg to mm
23:16 <rust_collector> i still don't get that thing about jumper cables
23:16 <electrohead> EEVBot: give beer to Ysjoelfir
23:25 <Ampera> what thing
23:33 <electrohead> whoops, we sent that at the same exact time
23:40 <electrohead> hsn: you forgot a space
23:46 <Ampera> wait you actually do awg?
23:49 <electrohead> EEVBot: convert 6 awg to mm
23:50 <EEVBot> electrohead: The result is 4.115378098506909 mm
23:56 <Ampera> good lord man, trim your decimals
24:00 <rust_collector> it seems to be a thing on reddit or some such place, about being beaten with jumper cables
24:04 <Ampera> significant digits, yo
24:06 <electrohead> lol
24:25 <hsn> Ampera: good enough for Lemon
24:25 <electrohead> I already have the function written to trim to X decimal places
24:35 <electrohead> so, that's easy to fix
24:43 <Ampera> I forget how I fixed that
24:44 <electrohead> what's a good number to keep it, at?
24:47 <rust_collector> we like Lemon , so try to keep him halfway satisfied with many zeros
24:50 <Ampera> I think I did a hard truncate for it all
25:07 <Ampera> a good number is an actual conversion library
25:17 <EEVBot> [Twitter] - eevblog - Alkaline vs Fluke https://t.co/eUgJALXdA1
25:20 <Ampera> instead of, for some reason, literally cloning my pure idiocy of a conversion matrix
25:54 <rust_collector> electrohead I think 4 is a good number
26:10 <rust_collector> if you need something specific, use a calculator
26:25 <electrohead> alright, should I use 4 decimal places for everything, you think?
26:26 <electrohead> I think so
26:27 <Ampera> there are rules of significance for conversions...
26:53 <Ampera> if you hard truncate and do a conversion from a small unit into a large, you lose all value
27:02 <rust_collector> it will probably be wrong no matter what you set it to... 4 os good
27:06 <Ampera> I forget what I did to solve that, if I did solve that
28:59 <Ampera> I guess I never did solve that
29:23 <Ysjoelfir> gn8 hsn :) thanks electrohead, I just got myself a glass of cocoa with amaretto. :P
29:35 * Ysjoelfir hugs Ampera
29:39 <Ampera> since I keep talking about contributing, I can look into an actual conversion engine for the bot, electrohead
29:48 <Ampera> I have no clue how python dependencies work however
31:22 <electrohead> it's easy
31:32 <electrohead> Ysjoelfir: drink some for me :P
31:55 <Ampera> I can also just do the conversion on the command line
32:12 <electrohead> also, I'm connected to UnderNet, and got a server side message before - https://www.undernet.org/news/irc-from-a-lawnmower
32:12 <EEVBot> [Title] - Undernet IRC Network - Undernet News
32:21 <rust_collector> so, just link EEVBoot convert to ampera?
32:29 <electrohead> ==> https://jotunheimr.org/users/jotun/lawnmower/
32:30 <EEVBot> [Title] - The Lawnmower IRC Server
32:37 <electrohead> not sure if anyone in here saw that, yet
34:07 <electrohead> I just talked to the creator of that monstrosity, he's a cool bloke :p
39:31 <Ysjoelfir> omfg xD
39:37 <Ysjoelfir> I mean... why? but.. its cool :D
40:00 <Ysjoelfir> though I would assume, judged by the name Jotunheimr.... its one from rustyland. that could explain stuff.
40:16 <electrohead> yeah for sure, lol
40:16 <rust_collector> logging distance on that thing was a really bad idea. He is going to be very fit, and have no lawn left
40:19 <electrohead> I love it :D
41:51 <Ysjoelfir> I do as well. SO nice xD
44:11 <rust_collector> well, say hi from me, if you talk to him again. I don't take offense to what he did
44:38 <rust_collector> yet
44:39 <electrohead> he actually lives here in the US, down south
45:19 <rust_collector> yeah, so it is much easier if you say hi
45:27 <electrohead> just did for you :p
45:42 <rust_collector> woohoo!
46:07 <rust_collector> ohcrapitisthatguyagain log off
48:07 <rust_collector> so, if he did that in a year or so... I wonder if he will be forced to upgrade the mower part of it some day, because.. you know feature creep, it can be hard on a small mower
48:40 <Ysjoelfir> lol :P
51:58 Join: hierbabuena ([email protected]) to #EEVblog
52:38 <rust_collector> what a weird webchat thing. it looks like it would work...
52:43 <steve30> kitty :) https://jotunheimr.org/users/jotun/lawnmower/pics/large/IMG_5000.jpg
54:46 <Ysjoelfir> green eyes?
55:11 <rust_collector> they have funny water down south
58:20 <electrohead> alright, closing time, I'll be around then o/
00:31 <hierbabuena> another week, another forum outage
00:44 * hierbabuena likes routine
00:55 <rust_collector> oh, are we going to have some traffic here again?
02:18 <T3sl4> https://i.imgur.com/bsy1nMR.jpg
03:25 <rust_collector> I wonder if you can deep fry that
03:54 <rust_collector> They don't seem to have anything in between out there on the island
04:56 <Ysjoelfir> That looks actually a bit... ew? :D
05:45 <rust_collector> they should have put it under a bright cold white led, to really make it look... meh
10:43 <rust_collector> oki. maybe it is nap time. I have a feeling someone will wake me up at around 5, so...yes
10:49 <rust_collector> good night
13:39 <Ysjoelfir> enjoy your nap :)
14:18 <rust_collector> well, there are a few videos I have to...
15:12 <rust_collector> it never ends
20:45 * Ysjoelfir is watching videos showing stupid translated product advertisments
20:49 <Ysjoelfir> I have no idea what you mean
21:10 <rust_collector> I am not sure either
27:18 Quit: Reg7805 ([email protected]) Quit: Going offline, see ya! (www.adiirc.com)
33:50 <electrohead> o/
35:21 <Ysjoelfir> mornings mr. head
35:45 <rust_collector> HELLO! dr mr head
36:06 <T3sl4> hello walnuts
36:06 <EEVBot> Hello, T3sl4!
37:48 <Ysjoelfir> so, T3sl4... do you think our melon will know about thevenins theorem tomorrow?
38:26 * T3sl4 shakes it
38:38 <T3sl4> the prognosis is grim
39:07 <Ysjoelfir> :O you need to have faith!
39:17 <rust_collector> well, not really
39:44 <rust_collector> YOU need that. the rest of us are ok
40:12 <Ysjoelfir> oh. damn.
40:19 <Ysjoelfir> but well, I can explain that without :D
40:23 <Ysjoelfir> I think
40:53 <electrohead> got my beer, got some food, I'm good to go.
41:01 <T3sl4> i haven't been paying attention, something about opamp abuse :P
41:15 <Ysjoelfir> nice. I have cocoa with amaretto and afri cola 25.
41:16 * electrohead films T3sl4 shaking it
41:36 <rust_collector> hmm, ok, more pizza
41:42 * T3sl4 swats that disgusting brown fluid out of Ysjoelfir's hands, replaces it with a tea
41:42 <Ysjoelfir> T3sl4, naaaaa. just trying to explain why shorting the output of an opamp to ground might be not the best idea.
41:55 <Ysjoelfir> uh, nice.
41:59 * Ysjoelfir adds amaretto to it
42:05 <T3sl4> lol
42:10 <T3sl4> tbf that sounds good too
42:55 <Ysjoelfir> it is.
43:45 <electrohead> to be fuck?
44:31 <Ysjoelfir> fair
44:49 <T3sl4> fuckly my dear electrohead, i don't give a fuck
45:00 <electrohead> :p
46:53 * electrohead hands my dear T3sl4 a dragon's milk
47:42 * rust_collector gives electrohead a dead badger in a box
48:22 <T3sl4> ok i lied, you can have a little fuck, as a treat
48:44 <electrohead> lol
48:47 <rust_collector> only a small one?
49:02 <T3sl4> yeah
49:11 <rust_collector> ok
49:13 <T3sl4> i took it from Ampera, he wasn't using it
49:19 <electrohead> hahaha
49:44 <Ampera> You'd have had to take it, I don't give those.
52:33 <rust_collector> I wonder why they have built a fake tunnel for the subway or train in paris.
54:29 Join: meteo ([email protected]) to #EEVblog
06:16 <Ysjoelfir> So... I find it quite hilarious. german media has been for some days like "OMFG this chinese rocket is falling down without control, its probably hitting something on land or a ship!!!!!!!!!!".... now the thing should already be down somewhere. I can't find ANY news where it dropped down. So I assume it was just a little *splash* and thats it.
07:30 <rust_collector> i bet the guy out fishing on his canoe will not agree on it being a little splash
08:16 <Ysjoelfir> probably
13:18 <rust_collector> write a comment, saying it fell down in the black forest or something OMG!!! luckily not many wild animals were annoyed
13:27 <Ysjoelfir> lol^^
14:25 <rust_collector> if everyone writes comments like that in papers here and there, someone has to go there and look for it
14:43 <Ysjoelfir> :P someone should do that
14:47 <Ysjoelfir> or... many
15:11 <rust_collector> the bad thing is that maybe they would find something there, that no one knew about
15:43 <Ysjoelfir> weeeell... I am not sure if that would happen
17:48 <rust_collector> well, I guess we will never know
18:19 <rust_collector> ok, good night
18:44 <Ysjoelfir> have enjoys :)
19:57 <MrMobodies> Hello
20:16 <MrMobodies> no eevblog
20:25 <MrMobodies> website seems to timeout
21:03 <Ysjoelfir> that is pretty corect
23:50 <hierbabuena> that's the new normal
26:15 <MrMobodies> yesterday I did some work on my firewall back tracked everything, couldn't understand why a laptop nic was unreachable after restarting it
26:31 <MrMobodies> you know what it turned out to be
26:48 <MrMobodies> two USB gigabit network adaptors can actually swap
26:52 <MrMobodies> randomly
26:58 <MrMobodies> after restarting it
27:14 <MrMobodies> so one interface is tagged on the switch port the other isn't
28:00 <MrMobodies> and it seems to switch the mac address over like it is not based on the hardware
28:26 <MrMobodies> I got tripped up on something so simple
29:21 <MrMobodies> hopefully it should be back to normal when I wake up
29:23 <MrMobodies> night
39:25 <hierbabuena> night
40:40 Quit: hierbabuena ([email protected]) Quit: Leaving
14:03 Quit: coppice_ ([email protected]) Quit: Konversation terminated!
09:37 * Halcyon stretches
12:14 <Ysjoelfir> why do you do such things?
14:18 <Halcyon> *shrug*
18:41 <Ysjoelfir> soooo.... we just watched a video about our main political party.
19:18 <Ysjoelfir> it was 20 minutes. 20 minutes of JUST NAMING which politician is involved in which fraud/corruption/crime
46:32 * T3sl4 shrugs Halcyon
46:52 <T3sl4> Ysjoelfir: you gotta pump up those numbers, those are rookie numbers
47:13 <T3sl4> see our last 4+ years, that's how you do it
47:19 <Ysjoelfir> is it? :D Keep in mind that we are A BIT smaller than the US of A^^
52:16 <T3sl4> maybe, but according to history, your german efficiency can get it done just as fast
53:36 <Ysjoelfir> you might got a point there
54:44 <Ysjoelfir> also, I am experiencing a strange weekend. I feel highly productive and have now been up for.... 23 hours. No feeling of tiredness yet.
55:40 <T3sl4> hmm. didn't accidentally ingest any amphetamines?
55:50 * Ysjoelfir coughs
56:32 <Ysjoelfir> No, I didn't accidentally ingest amphetamines.
56:50 <T3sl4> i wonder what it could be....
58:20 <Ysjoelfir> I have no idea
23:36 * electrohead hands Ysjoelfir and T3sl4 water
23:50 <Ysjoelfir> oi
23:52 <Ysjoelfir> where is my beer?
24:07 <T3sl4> jokes on you, i already have one!
24:59 <electrohead> it's gone, I drank it, water is to sober you up
25:01 <Halcyon> Heyyy electrohead
25:08 * electrohead stubles around
25:21 <Halcyon> Drunky
25:32 * electrohead face hugs Halcyon and falls on the floor
25:35 <electrohead> lol
25:38 <electrohead> :p
26:05 * T3sl4 shaves electrohead
26:35 <Halcyon> :P
27:20 <electrohead> my head is already bald, what are you shaving? ;o
27:50 * Ysjoelfir looks at mr. heads balls
27:56 Quit: bdunh ([email protected]) Quit: Going offline, see ya! (www.adiirc.com)
27:59 <T3sl4> no stubbling!
28:02 <Halcyon> Heh
28:23 <electrohead> that hair is barely visible, what else?
28:24 <electrohead> lol
28:42 * electrohead points at his ass
29:32 <T3sl4> Ysjoelfir: rub it for good luck https://vimeo.com/5250579#t=34s
29:33 <EEVBot> [Title] - Verify to Continue
33:38 <Ysjoelfir> lol
35:13 * Ysjoelfir puts on his hairpants
42:03 <electrohead> lol
50:02 * Ysjoelfir is redrawing some ancient logos from a coffee mill
50:08 <Ysjoelfir> that... is not fun.
52:41 <electrohead> free hand, or digitally?
52:58 <Ysjoelfir> digitally
54:51 <electrohead> what's your software of choice?
54:58 * electrohead is gimp all the way \o/
55:19 <Ysjoelfir> Affinity :)
56:03 <Ysjoelfir> https://drive.google.com/file/d/149hsDJmNswO0yM0Ltln9hWLMSHtyz-U-/view?usp=sharing original
56:04 <EEVBot> [Title] - 302 Moved
56:20 <Ysjoelfir> https://drive.google.com/file/d/10hG5uzTf4_lKYpJPGwXNi_3t4kIp3ME8/view?usp=sharing my remake
56:20 <EEVBot> [Title] - 302 Moved
01:20 <electrohead> you and your google drive files :P
01:27 * electrohead enables javascript
03:19 <electrohead> the blue can be a little bit darker, maybe?
03:47 <Ysjoelfir> #486880?
04:21 <T3sl4> number colors? what is this madness
04:24 <T3sl4> pantone or GTFO!
08:09 <Ysjoelfir> what is this imperial sorcery?
29:02 <T3sl4> or whatever equivalent pigment colorspace
29:16 <T3sl4> the joke is that it's pigments which are technically different from colors :P
31:53 <Ysjoelfir> eww, pigments. I prefer Dye :P
02:11 <EEVBot> [Twitter] - eevblog - Yes, the forum and website are down again. @GorillaServers claim it's our problem. @HostFission says othersie. My m… https://t.co/bMxsEZz4nW
28:15 <Ysjoelfir> sooooo, second logo done.
28:47 Join: Kuschelpony ([email protected]) to #EEVblog
34:46 <Ysjoelfir> https://drive.google.com/file/d/13yfxm3Qym4os9Zk90MbjbOSoOQGQeGva/view?usp=sharing old one
34:47 <EEVBot> [Title] - 302 Moved
35:02 <Ysjoelfir> https://drive.google.com/file/d/1lSBKh_IC_flIts-kthY9HIaiFIhtoBrw/view?usp=sharing my replica
35:03 <EEVBot> [Title] - 302 Moved
45:15 <rust_collector> lalalala
46:11 <rust_collector> la
54:11 <Ysjoelfir> welcome back rusty
54:15 <Ysjoelfir> did you have a good nap?
55:47 <rust_collector> eeh, not bad. I just tipped over on the couch, so everything hurts a bit. But there has been no barking or screaming, or anything
59:39 <rust_collector> this is almost like something I would do, if I had a country: https://www.youtube.com/watch?v=tPL9-L2gwzo
59:40 <EEVBot> [Title] - Youtube: The Lovely Swiss Villas That Could Destroy An Army
07:14 Join: IanM ([email protected]) to #EEVblog
07:54 <rust_collector> I like a pink fortress next to the road
08:18 <Ysjoelfir> nice. I was sitting on my chair, with gworg (who was not sitting on my chair), watching spacefrogs videos. so that makes me now awake for.... 26:30 hours
09:03 <rust_collector> right, that is a good start
11:04 <Ysjoelfir> did you see my remade logos, rusty?
11:11 <rust_collector> yep
11:36 <Ysjoelfir> what do you think?
13:07 <rust_collector> well, it is tricky to say... they are different but the same, you know. I think you are very close
14:08 <T3sl4> hrm, eevbog still down huh
14:14 <rust_collector> YAAY!
14:50 <rust_collector> and there is still more people on #lawnmower than here
15:29 <Ysjoelfir> "here" = austnet? or this channel?
16:13 <alfbaz> good evening group
16:24 * T3sl4 gives alfbaz a tall cold glass of water
16:36 <Ysjoelfir> T3sl4, what do you think about those? also rust_collector, thanks :) I think its better than no logos at all, but yes, I think it could be better as well. maybe make them look a bit more.. aged somehow
16:36 * alfbaz drinks it thirstily
17:05 <T3sl4> those, lawnmowers? they're alright i guess
17:21 * Ysjoelfir slaps T3sl4 with some logos
17:56 <T3sl4> yours looks... curvyier?
18:32 <T3sl4> also, so, you're getting into graphic design too i guess?
18:51 <alfbaz> what's with the asterix? *may not be favoirite or original :P
19:00 <Ysjoelfir> keep in mind that the thing it was on was... well... a motor. so it was on a round housing. so the perspective makes it a bit.... squished I think?
19:30 <T3sl4> no, i mean the letter forms
19:33 <Ysjoelfir> And I was into graphics design since I was 14. basically. But I stopped doing it for money for like...... 10 years and only do occasional stuff when I need it
19:50 <T3sl4> like, they could be just poorly vectorized, :P but i'm guessing you traced them
19:56 <T3sl4> ah neat
20:49 <Ysjoelfir> oh. I tried to follow the washed out lines, not the lines how they were when it was new. Idea was, that the thing will never look "new", so I kind of tried to make it look a bit more... "wobbly", and maybe make them a bit washed out at some places to make it look older. not sure if that worked out though
21:40 <T3sl4> it's... almost kinda sorta maybe a little like that blobby flower power 60s style lettering, just a tiny bit?
21:58 <Ysjoelfir> yep, that was a bit the intention.
22:22 <T3sl4> YAY!
22:24 <alfbaz> it worked, was the first thing that popped into mind for me
22:58 <Ysjoelfir> the thing is from.... erm.. ok, there is no date code on the plate.
23:19 <Ysjoelfir> except from the serial number. IF I assume they put a datecode in that I would guess its from 54
23:49 <alfbaz> what's it from Ysjoelfir?
24:19 <rust_collector> I think 54 is a good guess. from the shape and look of the thing
24:45 <Ysjoelfir> its from a Walter Michel Rekord "Original Favorite" Coffee Mill
25:04 <Ysjoelfir> www.ebay.de/itm/Alte-Kaffeemuehle-Original-Favorite-Walter-Michel-Hamburg-/174746011917 thats how it looked before I disassembled it
26:21 <alfbaz> ah ok
29:10 <Ysjoelfir> it has one of those nice old german color schemes in the cable
30:08 <rust_collector> brown and dark brown?
30:24 <Ysjoelfir> close. live is gray, neutral is.. well, gray as well, just slightly darker, protective earth is red.
31:07 <Ysjoelfir> that color scheme was used up until..... 65? so its at least before that.
31:18 <Ysjoelfir> *from before that
31:25 <Lemon> hi peeps :>
32:11 * T3sl4 plucks Lemon
32:27 <rust_collector> so, are you going to strip and repaint it? have you looked at the funnel part yet?
34:11 <rust_collector> do you have nice leaded paint, so it gets that nice niceness?
35:24 <Ysjoelfir> yes, I want to. and the funnel is pretty dented (as is every chrome part of the mill). also, the chrome is flaking off from many parts of it. So I think I have to somehow remove the remaining chrome and..... replate it with something
35:27 <Ysjoelfir> hi Lemon
36:03 <rust_collector> but it had a part broken off? is it steel, or?
37:10 <Ysjoelfir> yep, its steel. the funnel for the beans has the.... straight tuby part on the bottom that gets stuck into the mill is broken off. and someone tried to solder that back on, with what looks like a soldering iron. there was never enough heat in that
37:38 <rust_collector> ok, so that sounds doable
39:19 <Ysjoelfir> yep. I need to get a round nose hammer though, to kind of reshape the ex-chrome parts.
39:59 <Ysjoelfir> do you think I can add some kind of plating to it by electrolysis?
41:27 <T3sl4> some kind? probable
41:34 <T3sl4> the right kind, that's a tougher question
41:39 <Ysjoelfir> some kind that is food safe? :P
41:50 <Ysjoelfir> I don't need new chrome, afaik thats pretty impossible in a home lab
41:54 <T3sl4> oh. then no :P
42:05 <rust_collector> I am pretty sure you can... some kind. but if it would be anything close to chrome...??? I do remember a company in sweden that did a lot of chrome trim for people, with a small part or two, they also make the chromed plastic "tear off" part of torky roll dispensers
42:07 <Ysjoelfir> but maybe some thin copper coating or whatnot?
43:22 <rust_collector> and, is it chrome, or nickel?
43:27 <Ysjoelfir> erm
43:38 <Ysjoelfir> its flaky shiny mirror finish on dull grey metal
43:40 <T3sl4> think next best might just be, sand it down to bare steel and lacquer it
44:05 <rust_collector> plop it in lye, that is supposed to remove chrome, from steel
44:08 <T3sl4> it should be chrome on copper on iron
47:15 <rust_collector> the hamb says you can remove it by electolysis in battery acid, which sounds fun
47:51 <Ysjoelfir> the cats will enjoy playing with that! :D
48:00 <rust_collector> so, it seems either acid or lye will work... or sanding
48:01 <alfbaz> I'd be looking for local motorbike enthusiast groups etc, they love chroming bits and peices and could probably steer you in the right directio
49:07 <Lemon> Ysjoelfir can I bother you for a minute ? :>
49:19 Quit: Halcyon ([email protected]) Ping timeout: 121 seconds
50:37 <alfbaz> another guy on the tube worth looking at for ideas resotiring old chrome bits is "My Mechanics"
50:51 <alfbaz> https://www.youtube.com/channel/UCMrMVIBtqFW6O0-MWq26gqw
51:00 <rust_collector> https://bit.ly/3ete7v8
51:01 <EEVBot> [Title] - Bitly
51:56 <Ysjoelfir> I love my mechanics. :D Lemon, well... I am a bit tired, haven't slept yet. so... no idea if O would be muc help right now.
52:31 <Lemon> ho shit, you didnt sleep ? xd
52:38 <Ysjoelfir> nope
52:48 <Lemon> but its 11am !
52:53 <Ysjoelfir> thats correct
52:59 <Lemon> 6 am is the legal limit :>
53:00 <rust_collector> this evening, you can ask again, because then you will be at the same level, lol
53:26 <alfbaz> Ysjoelfir, that guy makes me look for old rusty things to fix :P
54:01 <Lemon> well, its mostly one question, you'll probably now even dead tired knowing your knowledge :> : on my schematic, you said the opa output fed by the negative rail was wrong
54:13 <Lemon> am I right ? or maybe I misunderstood ?
54:15 <rust_collector> meh, I wonder if Ysjoelfir is discovering the same as me, I seem to be made to be up for 2 days, then sleep most of one day
54:20 <Lemon> because I dont see how else it could be
54:59 <rust_collector> do you have the picture again?
55:26 <Lemon> because when I look at that schematic I drawn, it seems the only error I can find is the line feeding the opa277 which is 10v instead of vcc
55:36 <Lemon> https://imgur.com/UAqeUrf
55:37 <EEVBot> [Title] - Imgur: The magic of the Internet
55:40 <Lemon> I will correct it
55:43 <Lemon> that will be easier
57:16 <Lemon> https://imgur.com/8AohJuJ
57:16 <EEVBot> [Title] - Imgur: The magic of the Internet
57:23 <Lemon> here is it corrected, well, how I think it should be
57:55 <T3sl4> ok but pins 4 and 6 are still shorted?
58:15 <Lemon> pins 4 and 6 of what ? the ref ?
58:29 <T3sl4> the opa
58:31 <rust_collector> ok, so on the 277, the output and power ground and - input is all wired to ground?
58:57 <Lemon> hmmm yes thats right
59:03 <Lemon> so what should I feed
59:05 <Lemon> to the output ?
59:09 <Lemon> thats what I dont understand
59:16 <T3sl4> what are you doing anyway
59:27 <Lemon> a precision current source :>
59:56 <Lemon> so the vref is being amplified by the lt1001, which then is buffered by the 277
00:16 <Lemon> but I dont fully understand everything, Ysjoelfir greatly helped yday until I went in a mental breakdown
00:27 <Lemon> because I feel incredibly diminished due to drug rampage years ago
00:35 <T3sl4> well, if the load shall be common ground, then you need a voltage sense resistor above it
00:36 <Lemon> but I refuse to let it go till I fully understand
00:37 <rust_collector> i think you have to move the 277 a bit further to the right, then figure out what you want to buffer with it
01:27 <T3sl4> erm, current sense* resistor
01:41 <T3sl4> from which the opamp(s) read a voltage
02:07 <T3sl4> and that sense resistor needs its voltage sensed differentially, since its voltage wrt ground includes load voltage
05:10 <Ysjoelfir> couldn't you come to a result if you break the connection between 2 of the 399 and R2 and move 4 of the 1001 to GND? then the 277 should just provide a floating reference for the 1001, canceling out the error induced by the load
11:17 <Lemon> https://imgur.com/q9QIjpe
11:18 <EEVBot> [Title] - Imgur: The magic of the Internet
11:20 <Lemon> like that ?
12:01 <Ysjoelfir> yes. though I might be not 100% clear in my head right now
12:52 <rust_collector> if the 399 still does its thing like that, it looks right to me? (which means almost nothing)
13:27 <Lemon> im just not sure of what is fed to the opa277, its 10v ok but there is 2 resistors on its way
13:41 <Ysjoelfir> no, it is not 10V
13:52 <Ysjoelfir> it is the voltage drop over the load
14:58 <Lemon> so everytime we load the circuit
15:04 <Lemon> lest say we rise the resistance of the load
15:15 <Lemon> that voltage is "added" by the opamp to compensate the loss ?
15:34 <T3sl4> it's... closer? but it's still a fixed voltage at LT1000001 +in, which lies somewhere in the middle of the sense resistor's voltages
15:48 <T3sl4> i.e. with respect to gnd, not independent of Vload
15:59 <T3sl4> seems like you want one of these things instead, https://www.ti.com/lit/an/sboa437/sboa437.pdf?ts=1620551658623
16:48 <Lemon> https://imgur.com/kxpxz7y
16:48 <EEVBot> [Title] - Imgur: The magic of the Internet
16:53 <Lemon> I based myself on that
17:47 <T3sl4> er well, LM399 isn't REF102, and you tied the one end hard to ground anyway so it's nothing like that? :)
18:02 <rust_collector> https://imgur.com/gallery/bliixAE
18:03 <EEVBot> [Title] - Bad place to put a pole - Album on Imgur
25:08 <Lemon> I think its simply too complicated for me now
25:35 <Lemon> guess I will continue wanking in front of my digits
26:42 <rust_collector> Ysjoelfir now that you are a bit into woodworking...
27:03 <rust_collector> https://bit.ly/3faOr5U
27:04 <EEVBot> [Title] - Bitly
27:37 <Lemon> I will order some lm317 and play with that
27:41 <Lemon> and some opamps
27:52 <rust_collector> OPAMPS! wheee
28:37 <Lemon> and what is a lm317T vs regular ones anyway
28:42 <Lemon> is it much different ?
28:47 <Lemon> is it just the package ?
29:23 <Lemon> I cant open TI website
29:25 <Lemon> for some reasons
29:27 <rust_collector> if I remember right, the T is the little to92 thing, and it has a max currrent of 0.1A
29:55 <rust_collector> or maybe not
30:12 <Lemon> https://www.ebay.fr/itm/264712005719?_trkparms=ispr%3D1&hash=item3da210a857:g:9VIAAOSwal5YIz4t&amdata=enc%3AAQAFAAACcBaobrjLl8XobRIiIML1V4Imu%252Fn%252BzU5L90Z278x5ickkXKoKcbeZcOrOku%252BoOBl%252BS%252FNSRhsFkf3Pno8bVQ6s69%252FRcHVJ2Sw0Looi%252BYsgTPdDh%252FR9aSbDJgyOikEh5TRB%252F%252BGWzPf5WEkDVhzWHlWkLnzteUuQwtGJae8H1w1zsx63CPSbo9waTSfmuhmhvTaAFKU058fBefbkLDZreLGJ9NBHAbSH4NeZ0EC39UeyjHRZ66abdONmWJEDbcMgXc0gd63g7%252Bhf6wk4mjvDxccI3c
30:12 <Lemon> 3K4Lwiv9ypxwZffq5UTUVg9QkPQrFhnAxqp47rundMTnFcdcMnzGqCOXAydXUXcxOLcyzcy0HTQdEOJJeNmbn%252ByDTsxtplIqO6jWYWwkror3%252BUDyoIX1%252FkYdY4oEoHWNYc3jr2RXgpFKo%252BbAC5bXkKe1RK30vnqy1ACxKJFLwWnmhQc1NixfGqFWoY0%252BXZOvV4UO%252FKWmAhL7UkJ%252FaWUMb54Vn1K3BvV%252Fa0ptK%252BHEhl9URQ46Ce70MfgoctBIumZ3xR3A1QWFc77TYOxIPwpoey%252BfcxOzHW6LfkygrsC9168W011B2CVf8RLCVPIQIEJMvmdRmXyrmm%252FDrUO5DT8HaVwNnHGNqE4me7hTJMFEzwjY%252BKJ2flh5Qta7MVdE76CDiZPeqZ
30:13 <Lemon> i22nkrEUdFfWxfbsiMfR0QpD%252FuTg2RAoj%252BNXGnA%252B18vMPu3TOwAh0Q97rE2Kddn6FBIIiV5QqnwX9BPHORif6hBv%252Bo8y81s7b7PCz64pF%252BZ4tItqpCJvgcgPiKsz2zPfncUH0TZoEZ2zEZGg%253D%253D%7Ccksum%3A264712005719eaa02b49efad45ec9fc1a905d82a17fc%7Campid%3APL_CLK%7Cclp%3A2334524
30:13 <EEVBot> [Title] - LOT 5X LM317T Regulateur de Tension Ajustable ST LM317T TO220 | eBay
30:20 <Lemon> jesus why the fuck are those links like that
30:23 <Lemon> anyway
30:32 <Lemon> its a 3 pins package that can be tied to a heatsink
31:42 <rust_collector> yes, I was probably thinking of some other letter. don't worry about it. get any in a to220 or so, I think the only thing is the hv version, which can handle a little bit higher voltage
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33:08 <Lemon> 1.5amp max
33:10 <Lemon> I guess thats fine
33:17 <Lemon> but I want one that is stable
33:30 <Lemon> I saw 0.01% regulation in the datasheet yday
33:33 <rust_collector> well, don't count on it doing 1.5A
33:38 <Lemon> idk if they are all like that
33:44 <Lemon> yeah I just want a few hundreds of ma
34:14 <rust_collector> ok, it was the "L" version, that was the smaller one
35:19 <Lemon> the T version isnt as good ?
36:01 <rust_collector> I am sure it will be as good as any other. I have no idea what it means
36:41 <Lemon> yeah because if I use batteries to have a nice clean voltage and destroy it with that
36:46 <Lemon> its of no use
38:06 <rust_collector> no, it is still a linear regulator. even if it says T on the end. how much is that batch of 5?
39:06 <Lemon> I found 10 for 3.6 euros
39:07 Join: Duddley ([email protected]) to #EEVblog
39:10 <Lemon> delivered in a few days
39:20 <Lemon> yeah screw it its good enough
39:22 <rust_collector> that is not too bad
39:34 <rust_collector> just get something and play with it
39:43 <Lemon> ok what opamp can I get then
39:51 <Lemon> not too bad but not too expensive either
39:56 <Lemon> maybe the seller got some
40:27 <rust_collector> Unless you go for some very special ones, I don't think they will be very expensive
40:37 <Duddley> Did the cooking section fry the forum or something?
40:37 <rust_collector> no matter what their name is
40:59 <rust_collector> Yes, it was that rant about fried seafood
41:38 <rust_collector> it had some hidden scripts in it, which made the servers overheat
42:28 <Duddley> Too much snake oil in a hot wok probably.
42:36 <rust_collector> we assume it was the chinese government, yes
43:41 <Lemon> I want a simple opamp
43:48 <Lemon> I keep finding shit with 34432432 channels
43:58 <rust_collector> channels?
44:34 <Lemon> yeah seems theres multiple opamps in a single package
44:42 <rust_collector> well, if you want something very simple, and somewhat meh, but pretty fun to mess with, just get a couple lm358
44:46 <Lemon> and it also develop itself over time till he can speak and steal your car
44:52 <rust_collector> that is a dual one
45:26 <Lemon> I want a lt1001 but not as good
45:28 <Lemon> and cheaper
45:42 <Lemon> something simple that I can use like it
45:56 Part: Duddley ([email protected]) from #EEVblog
46:09 <rust_collector> ok, good luck
47:09 Join: JoePublic ([email protected]) to #EEVblog
47:12 <Lemon> I want some parts I can play with, to learn
47:19 <rust_collector> yes
47:20 <Lemon> and make for example a small current source
47:23 <Lemon> or whatever
47:28 <Lemon> but not with expensive shit
47:32 Quit: JoePublic ([email protected]) Quit: http://www.kiwiirc.com/ - A hand crafted IRC client
48:14 <rust_collector> so, get some random cheap opamp, what does your guy have?
48:54 <Lemon> well this g uy nothing only expensive shit
48:58 <Lemon> so lets look somewhere else
51:20 <Lemon> hmmm
51:24 <Lemon> most got offset pins
51:28 <Lemon> offset trim or whatever
53:30 <Lemon> https://www.ebay.fr/itm/331984336983?hash=item4d4bcef857:g:2YwAAOSw0gdXTIn~
53:32 <EEVBot> [Title] - LM358P Amplificateur opérationnel (Expédié depuis la France) | eBay
53:33 <Lemon> this one you said ?
54:32 <Lemon> I found 10 for 4 euros
54:56 <rust_collector> yeah. that is a very basic one, double. it is handy for general tinkering, but it is not a super-awesome part. it has some issues here and there
55:25 <Lemon> like what issue ?
55:29 <Lemon> I will take those I guess
55:43 <rust_collector> but for playing with opamps, as a starter, I think they would be good
55:44 <Lemon> if I can do the same thing than expensive ones, just not as good
55:46 <Lemon> im fine
56:01 <Lemon> its just to learn how it works
56:55 <rust_collector> I think T3sl4 mentioned some crossover distortion stuff some time, I don't know. i just know they are not awesome.
57:23 <rust_collector> but you can play a lot with them, and figure out how they react and such
57:30 <Lemon> yeah thats perfect
57:33 <Lemon> ok what else
57:37 <Lemon> some cheap vref
58:36 <rust_collector> hmm, I guess cheap... maybe the tl431 would count as a sort of voltage reference-ish thing?
58:37 <Kuschelpony> my personal opinion of the LM358 is that it is an good opamp for average stuff, to tinker with
58:50 <Kuschelpony> yes the tl431 is
59:18 <Lemon> ok lemme read on them thanks
59:33 <Kuschelpony> the lm358 has the benefits that its easily available everywhere, and that its "single supply" where the inputs work down to 0v
59:34 <rust_collector> I think you could make something pretty nice with that, maybe not super perfect, but pretty good?
00:06 <rust_collector> and for 1/20th of the price of something very ok
00:12 <Kuschelpony> the lm358 is shit for anything precision, distorts significantly in audio and is very slow for anything above some kHz
00:23 <Kuschelpony> yep
01:16 <Lemon> theres the A and AC version
01:39 <Lemon> and normal
01:44 <Lemon> which one should I chose ?
01:45 <rust_collector> I am still annoyed by my small pile of lm324s, that I got a long time ago, and never use, because they have sooo many pins
01:49 <Lemon> seems its a temperature difference
02:21 <rust_collector> Lemon if it is in the package you want, I am sure any letter will be fine
02:35 <Lemon> yeah but they are the same price so I'd rather now first
02:42 <Lemon> seems theres 0.5% to 2% accuracy versions
02:53 <Lemon> and if its the same price...
03:02 <Lemon> that would be dumb to take the shittiest one
03:09 <rust_collector> and different manufacturers probably have different specs too
04:00 <Lemon> ok AC seems a bit better
04:02 <Lemon> lets take those
04:29 <Lemon> lm358P
04:31 <Lemon> idk what the P is for
04:35 <Lemon> there is so many variations
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04:56 Mode: (by ChanOP) +o gnif
05:25 <Kuschelpony> i have no idea how things are today, but decades ago parts were selected like the very low noise opampsa got stamped TL071 while the average ones got TL081 but over the decades things improved that all met the better specifications so they got just random prints depending on orders, and also the same price
05:26 <rust_collector> plastic package, I think
06:15 <Lemon> hmmm ok I see
06:28 <Lemon> I have many 18650 cells, could be nice to get bms for those
06:32 <Lemon> or no
06:34 <Lemon> not now idc
06:39 <Lemon> I will use my lab supplies
06:46 <Lemon> and simulate them
06:58 <Lemon> like make a 317 circuit and feed whatever with the lab supply
07:13 <rust_collector> 18650 cells should be banned. they pile up everywhere, lol
07:16 <Lemon> I have various diodes, caps already
07:25 <Lemon> resistances I have a shitton
07:33 <rust_collector> pots?
07:43 <Lemon> hmmm
07:54 <Lemon> I will get some trimmable ones you know
07:56 <Lemon> with the screw
08:01 <gnif> site is back up if anyone was waiting on it
08:25 <Lemon> https://www.ebay.fr/itm/183919248148?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20201210111314%26meid%3Db66acee0bcfe42f78e163dd1f87fb7d9%26pid%3D101195%26rk%3D1%26rkt%3D12%26mehot%3Dpf%26sd%3D293656711779%26itm%3D183919248148%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv9PairwiseUnbiasedWeb&_trksid=p2047675.c101195.m1851
08:25 <gnif> https://twitter.com/HostFission/status/1391330194871361544
08:27 <EEVBot> [Title] - Boite 50pcs Potentiomètre variable multitours vertical Trimpot 3296W de 500 à 1M | eBay
08:28 <Lemon> that is fine I guess
09:16 <rust_collector> ok, that works, but maybe get a few knob style ones? trim pots are... for trimming, I guess. but yes, those are probably handy to have too
09:38 <Lemon> yeah I will take those too
09:39 <Lemon> brb
12:33 <rust_collector> Lemon do you have heat sink gloop?
13:03 <rust_collector> if you want to play with a 317, you probably want a heat sink on it
13:53 <rust_collector> (which reminds me that I should put some of that in my crap supply)
20:49 <rust_collector> hehe, that thing still looks just as crap as I remembered it, lol
21:52 <rust_collector> and it still uses a coke bottle cap as the adjustment knob. it is pretty nice and grippy, and has a good size....
22:31 <EEVBot> [Twitter] - eevblog - Yep, not the servers fault. @HostFission was right. Website and forum now back up.
28:33 Quit: Kuschelpony ([email protected]) Connection closed
34:40 <EEVBot> [Twitter] - eevblog - Dogecoin collapsing after Musk calls it a hustle on SNL! LOL
02:20 <Lemon> ha yeah I need paste
02:26 <Lemon> I have some but for cpus, and its expensive one
02:49 <rust_collector> well, it would work, but yes
03:10 <rust_collector> better than toothpaste mixed with olive oil
03:47 <Lemon> ho I still have pads too
03:57 <Lemon> a large square that I use to redo laptops, gpus etc
04:01 <rust_collector> yeah, well...
04:01 <Lemon> I have enough left
04:06 <Lemon> for heatsinks hmm
04:09 <Lemon> I usually keep them
04:28 <rust_collector> yeah, but it is not really the same.
04:36 <Lemon> why that ?
04:41 <Lemon> I mean it transfers quite well
05:01 <rust_collector> yes, quite.
05:03 <Lemon> https://media.ldlc.com/r1600/ld/products/00/03/36/83/LD0003368318_2.jpg
05:07 <Lemon> this kind of thing
05:30 <rust_collector> and it does not leave everything covered in greasy fingerprints
06:10 <rust_collector> so that is nice
09:32 <Lemon> something I wanted to test is those electronic fuse
09:37 <Lemon> or whatever its named
11:02 <rust_collector> that does not sound very exciting?
13:08 <Lemon> it can be nice to protect an input
13:27 <Lemon> ho, and https://www.leboncoin.fr/bricolage/1930776082.htm?ac=206978287
13:28 <EEVBot> [Title] - leboncoin.fr
14:51 <rust_collector> so, you have gone from all the zeros, to half on one?
15:19 <Lemon> heh :>
15:28 <Lemon> idk, it looks so neat, with the leather pouch
16:33 Quit: IanM ([email protected]) Quit: http://www.kiwiirc.com/ - A hand crafted IRC client
16:45 <Lemon> https://www.leboncoin.fr/bricolage/1929963815.htm and this is the stripper I bought btw
16:46 <EEVBot> [Title] - leboncoin.fr
26:30 <Lemon> ok, I bought some lm317t, tl431ac, and lm358p
28:05 <rust_collector> that should keep you busy for a few hours
30:30 <Lemon> yeah
30:39 <Lemon> I still need a decent handheld dmm tho
30:57 <Lemon> I saw this one, that seems quite good https://www.leboncoin.fr/bricolage/1941891384.htm?ac=206978287
30:58 <rust_collector> yeah, maybe you should get one?
30:58 <EEVBot> [Title] - leboncoin.fr
31:32 <rust_collector> that looks.... very generic?
31:33 <Lemon> specs are nice but I cant find a video of it
31:41 <Lemon> well metrix is a good brand
32:03 <Lemon> 6000 points, various low ranges for current, backlight etc
32:17 <Lemon> 0.1% accuracy is perfect on DC, and DCI is decent too
32:25 <Lemon> ACI etc too
34:00 <rust_collector> ok then, go go go
34:39 <Lemon> well I like to have a video of it
34:43 <Lemon> to see if its well built
34:51 <Lemon> if continuity test is good, for example
34:56 <Lemon> because shit I hate slow ones
35:15 <Lemon> I want an instantaneous one
35:26 <rust_collector> get an unlatched one? they are super fast, but still crap
36:06 <Lemon> crap in what sense ?
36:13 <Lemon> and that dmm220 got bad reviews, so yeah nah
36:43 <Lemon> older metrix seems nice
42:31 <rust_collector> many things are nice
56:00 Quit: Ysjoelfir ([email protected]) Changing hosts
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56:10 Mode: (by ChanOP) +o Ysjoelfir
56:26 <rust_collector> https://www.ebay.com/itm/184696411950
56:28 <EEVBot> [Title] - Vintage HARTMAN & BRAUN 12-124-6177 600V 15A / # T 2671 | eBay
56:38 <rust_collector> that is pretty neat, in its own way
00:55 <rust_collector> Lemon how about one of those dmm/clamp meters in one, if you want it for general around the house things?
01:16 <Lemon> yeah I looked for them too but remember, I bought a nice clamp
01:21 <Lemon> so I'd rather get a regular dmm
02:44 <rust_collector> heh, I sort of like things like this, but I don't really want one, and I especially do not want to pay that for one: https://www.finn.no/bap/forsale/ad.html?finnkode=217944850
02:46 <EEVBot> [Title] - Elektronisk utviklings/opplærings sett | FINN.no
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19:43 <Lemon> its a fun thing yeah
26:33 Join: TheWelshRabbit ([email protected]) to #EEVblog
31:41 * Ysjoelfir puts TheWelshRabbit into his oven
33:07 Quit: TheWelshRabbit ([email protected]) Quit: http://www.kiwiirc.com/ - A hand crafted IRC client
33:36 <rust_collector> your oven needs better wifi, I think
33:44 <Ysjoelfir> awww, it wasn't even done yet!
33:49 Join: TheWelshRabbit ([email protected]) to #EEVblog
34:32 * TheWelshRabbit hops away
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06:49 <rust_collector> hmm, on my project "ancient power supply" say I use a 2n3055, as an example. and I need a transistor to drive that...
07:02 <rust_collector> can that driver transistor have too much gain?
08:32 <Kuschelpony> unlikely, usually it has not enough
09:03 <Kuschelpony> i would have recommanded the 2N3054 and 2N3053 as drivers but they became pretty rare
09:44 <Kuschelpony> of course i see why they aere not used anymore but i love the nostalgic feeling espically of the 2N3054 case
10:35 <rust_collector> yeah. I am just looking at what I have laying around, i do have some tip120s, I think they could do it.
11:46 <rust_collector> in the end, I am going to use a kd503, but looking for info, saying 3055 makes more sense, I guess
12:20 <Kuschelpony> hihi the east german transistors
12:49 <rust_collector> this one is a tesla, so I guess czech
13:11 <rust_collector> it is pretty beefy, and I do like the way it looks
14:10 <rust_collector> heh, it weighs 17 grams
15:29 <Kuschelpony> its with many old parts, where they had so much production spread that the had to significatly oversize them, so that the last 2% reached specifications, the other 98% were well above
15:50 <rust_collector> that makes sense
17:28 <rust_collector> I guess I will try the tip120, it can only not work...
17:29 <Kuschelpony> as i mentioned about the TL071 and 081 before
17:49 <Ampera> https://cdn.discordapp.com/attachments/635631712113786890/840939818648993822/20210509_091329.jpg
17:58 <Ampera> Not a server rack, but it's close enough
18:16 <rust_collector> what? no ikea rack? lol
18:27 <Kuschelpony> i cant remember the name of my favorite transistor case, its like the next bigger past the TO247 turned 90° and has two screw holes left and right of the chip, instead of one above, were available mostly from Sanken
18:32 <rust_collector> Kuschelpony yes, naming after testing
18:45 <rust_collector> oh
18:49 <rust_collector> interesting
19:31 <Kuschelpony> the had great thermal performance, but also were somewhat easy to break if you turned the screws too uneven
20:15 <rust_collector> I always thought putting a screw up on top there just looks wrong. But I guess it works well enough
20:24 <Kuschelpony> these https://www.richis-lab.de/2SC2922.htm
20:25 <EEVBot> [Title] - Sanken 2SC2922
21:04 <rust_collector> that is a pretty chunky part
21:09 <Kuschelpony> yep, using the screw on top does work in a mostly satisfying way but for maximum poerformance you better use something left and right and a "bridge" pressing over the transistor in the middle
21:22 <Kuschelpony> i had serviced many hi-fi amps in the 90s
22:43 <rust_collector> 180v, that is... a bit
23:45 <Kuschelpony> it was just a random of several of these power transistors, as said i loved them
24:02 <Kuschelpony> you had to have a major problem in a PA am to kil lthem
24:26 <Kuschelpony> or a consumer amp used for PA which ran great until everythign was hopelessy cooked out
25:17 <rust_collector> i think I have seen those, but not as transistors, maybe it was an amplifier ic, with many legs. but probably the same case style
26:47 <Kuschelpony> hmm thats something i dont remember
27:04 <rust_collector> well, maybe I am wrong.
28:36 <Kuschelpony> what i know are hybrid cirsuits but they are then 8 to 10cm wide, and 5cm long
28:44 <Kuschelpony> like the STK4040 and all
29:00 <Kuschelpony> did a few rebuilds with discrete transistors when they were hard to get
29:53 <rust_collector> yes, maybe. i do not really know, or remember where I would have seen one. I just see it is something I am not interested in, and keep looking.
30:13 <rust_collector> it could have been bigger
38:11 <Kuschelpony> i just read an extremely well written explanation of how digital sample rate conversation really works, did not immedaiately understood the things i had only a vague idea for decades
38:14 <Kuschelpony> https://www.diyaudio.com/forums/digital-source/28814-asynchronous-sample-rate-conversion.html
38:15 <EEVBot> [Title] - Asynchronous Sample Rate Conversion - diyAudio
38:51 <Kuschelpony> sometimes this forum still has gems, between the audiophool stuff
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