This circuit, found in a 1964 US documentation, consists of a selective amplifier that lets only 10 Hz pass around a 400 Hz center frequency with the indicated components.
This circuit is from 1968 General Electric documentation. It can certainly be adapted for any...
This tester from a 1960 magazine is only for capacitors with insulation voltages above 200 V (110...
Found in a 1991 publication this circuit can be assembled with more modern components. We can use...