In the 110 V network, capacitors of 200 V or more and in the 220 V network, capacitors of 400 V or more, can be tested in this simple circuit. The indication is given by a neon lamp.
The circuit shown is from National Semiconductor, having been found in the 1994 Linear Application...
We found this circuit in a 70s American documentation. The integrated circuits are from that time....
This circuit is from a 1978 French magazine Electronique Pratique. The magazine no longer exists, but...