Capacitor ESR meters

[bob91343]

ESR meters are easy to build. Put a high frequency current through the capacitor and measure the voltage drop. The frequency has to be high enough to neglect the reactance, so all that's left is the resistance.

You can get fancy by using a bridge but then you have a bit of calculation before you get ESR, not convenient for quick tests.

There are lots of ESR meter projects on line. I started to build one until I found out my bridge automatically reads out ESR.