Design of an ESR Meter from Practical Television 1999

[Wil_Bloodworth]

Here is some test cap pics, the daggum thing looks to be right on the money. The meter pictured ranges from 0-300uA so at the 10 mark is 100uA or zero ohms. Tested 3 caps, one at under 1, one at 3 and one over 40 esr respectively. Meter scale and board pic also attached. Also the oscillator set at 5v peak to peak at pin 1 of U1. Frequency is off a tad but close enough. The bulb used was a JKL COMPONENTS / 6838 in the oscillator.

Very nice!

[RoGeorge]

Nice! 

Do you happen to have any battery at hand?  It should be possible to tell which ones are discharged by measuring their internal resistance, or to tell which rechargeable from the same lot got more damage with time.

[Tim88]

I want to get that protection circuit installed before I go checking any batteries.

[skipp]

Buy a kit and build one that's what I did. I am only just a beginner myself. but look on aliexpress they have them fairly cheaply.

[Hamelec]

I don't know any kit which is able to measure the ESR incircuit and under supply voltage, like this one

[Tim88]

Finally got the ESR tester done, found a very cool enclosure for it for $10, link below. I also attached a couple meter scale pics one colour and the other not.

https://www.aliexpress.us/item/2255800409490545.html?spm=a2g0o.order_list.order_list_main.11.12de1802Jjm7fX&gatewayAdapt=glo2usa





 meter bw.pdf (783.16 kB - downloaded 40 times.)

 meter colour.pdf (797.6 kB - downloaded 37 times.)

[soldar]

Variations of this design have been going around for quite some time. I had one on my web site for many years and that page gathered many visits.

Poptronics magazine in July 2001, page 25.

Italian magazine Nuova Elettronica issue 212 dated October 2002

IZ7ATH also published it in QSL.net

Edit: It is not the same circuit. The one I mentioned uses a bridge of four resistors and a single TL084.