This circuit uses only one tube and is powered by the mains. We found it in a September 1945 publication. The instrument may be the corresponding scale of a multimeter. The circuit tests capacitors from 10 nF to 4 uF.

This circuit uses only one tube and is powered by the mains. We found it in a September 1945 publication. The instrument may be the corresponding scale of a multimeter. The circuit tests capacitors from 10 nF to 4 uF.