We found this circuit in a Japanese publication in 1967. The circuit consists of a 15 W audio amplifier with germanium transistors including a voltage indicator power supply.
July 2017 - Microchip's new MCP9V91 operational amplifiers with input offset and low drift voltage...
When the sensor, an ordinary photo-transistor, receives light, the relay closes its contacts. The...
Found in a 1964 Electronic Design, this circuit suppresses arcs that occur in contacts when a...