The simplest, cheapest ESR meter circuit

[abdulbadii]

Any experienced expert in creating some testing instrument here ?

What'd the simplest, cheapest and most practical ESR meter circuit be, requiring only 6 V PS (not 9 as usually) while it's reliable enough to perform a test with ~ 2% (or even just 2.5%) tolerance

[ledtester]

https://eevblog.com/forum/projects/5-transistor-esr-meter-design/

[kripton2035]

lots of ideas here : http://kripton2035.free.fr/esr-repository.html
the easiest today is the one above, or the same adapter from the same author : http://kripton2035.free.fr/analog%20esr/esr-dmm-adapter-.html

[Hexley]

This one will run off 5V directly, or 7V if you use the on-board regulator. Simple to build -- just a single op amp. http://ludens.cl/Electron/esr/esr.html

[BrokenYugo]

Runs straight off a 9V, but there is also this 6 transistor design also from Jay_Diddy_B that interfaces with a DMM at 100mV/ohm. I haven't built it yet, but like that it's all generic transistors and doesn't require finding/buying a $10 50uA meter that doesn't really appear in more modern and modest junk boxes. Only trouble is it seems nobody else built it yet to prove that it's a stable easily reproduced design like the other two from them, I intend to breadboard it eventually, build it through hole on perf board if that works, probably this winter when I dig harder into my project backlog.

https://www.eevblog.com/forum/projects/10-transistor-esr-meter-adapter/

[CMTan]

Hi All,
Anyone wants to build one can also use the design I did.  This is based off the Luden's design, but being a design engineer I have to evaluate the flaws in this design and to correct it as much as possible.  Not perfect, but definitely better and can be build with consistence performance.  I have also some question for developer to think about, so as to understand the design at a deeper level.
https://electronicsdesignfun.blogspot.com/p/esr-meter.html