Circuit Project Electronic

If you repair switch-mode power supplies, TV receivers, computer monitors, vintage radios, or similar equipment, and/or if you need to measure very low values of resistance, this project can save you lots of time and aggravation - as it has for me. It measures an aspect of electrolytic capacitor performance which is very important, but normally very difficult to check: the equivalent series resistance, or ‘ESR’.

Micro-based ESR meter
Necessity is supposed to be ‘the mother of invention’, but desperation works even better and I designed this ESR meter from scratch. It’s based on a versatile Zilog Z86E0408 or Z86E0412
microcontroller - which already has two voltage comparators and two flexible counter/timers built in, greatly simplifying the rest of the circuit. A micro also allows the easy incorporation of some ‘user-friendly’ features…
Source: http://testmeasurementcircuit.blogspot.com/2008/07/
esr-and-low-ohms-meter.html