Found in a 1967 General Electric documentation, this meter uses Nixie tubes, popular at a time when LED and liquid crystal displays did not yet exist.
Approaching the hand or an object to the sensor of this circuit, the relay closes its contacts. The...
For those who want to recover an old multimeter of this type, the circuit presented is worth...
The circuit shown is only for analog telephone lines. I found it in Popular Electronics (1991). It...