Very simple OP-Amp Tester - Page 1
Forum section: electronics / testgear

author: Martin72
author_rank: Super Contributor
timestamp: October 09, 2022, 04:55:04 pm
content: Hi,Here´s my very, very, very simple op-amp tester, based on anelector projekt.Circuit is the same, I´ve designed the layout different and corrected an issue with the supply-polarity of the quad-amp socket (plus twisted with minus).It can be used on single-, dual- and quad op-amps types with the same pinout (TL071, 072, 074, NE5532, 34 and so on).A biploar squarewave of about 1Hz will be generated and feed the DUT sockets.They are in such manner connected that the test op-amp will work as a buffer.Very simple...But it works.Of course it´s for rudimentary Go/No Go Tests, nothing else.But better as nothing to have..Short video with a TL074 inserted:https://youtu.be/Rq2O61mSrSkMartin

author: Martin72
author_rank: Super Contributor
timestamp: October 09, 2022, 09:05:57 pm
content: CAM output for the tester, just load this zip file up to for example JLCPCB to get the pcb build.All my self designed pcbs in the last 3yrs I´ve bought from them, good quality for an insane price, with one exception.You must take care what placement of the...the...argh, didn´t know the right explanation in english...What the name positions of the elements on the pcb concerns, e.g. R4, R2 and so on..If you leave it as it is, names could be covered by the body drawings.But this is the only con, the rest is high quality.The CAM output also contains the BOM.Martin

author: Messtechniker
author_rank: Frequent Contributor
timestamp: October 09, 2022, 09:29:03 pm
content: My circuit herehttps://www.wellenkino.de/557/viewtopic.php?f=7&t=358goes a bit beyond opamp testing since it was developed for selecting opamps for offset. Might be of interest to you.

author: Martin72
author_rank: Super Contributor
timestamp: October 09, 2022, 09:40:55 pm
content: Wow, not bad.Could be interesting when you can´t control the offset directly.(Or you don´t want to offset the amp by using resistors from Ub to his inputs)Next thing planned was a circuit similar to the tester but for comparators explicit.I think I took a triangle signal for it.And then taking both together.

author: ledtester
author_rank: Super Contributor
timestamp: October 09, 2022, 11:53:54 pm
content: One test I've used to distinguish real TL082's from fake ones is to put it the oscillator circuit in this post:https://www.eevblog.com/forum/beginners/op-amp-square-waves/msg922779/#msg922779This is basically a test of the op-amp's slew rate -- the higher the slewrate the higher frequency it can generate. Perhaps that would be another good test to have in an op-amp tester.

author: Martin72
author_rank: Super Contributor
timestamp: October 10, 2022, 09:05:08 pm
content: Hi,Yes and no joke, that was the first testcircuit I´ve realized on a breadboard..And wondered how dramatical the difference between a TL072 and LT1013 was, in case of bandwith.To test both amplifiers on a dual-OP amp I´ve used the well known circuit for a squarewave-triangle gen.But a scope is needed and I want to have a stand alone version.But why not combine all circuits on one board....Hmm...A lovely idea.To be continued.