This current switch was found in a Radio Electronics from November 1957. It triggers the current determined by the electromechanical sensor, a polarized relay of the time.
We found this transmitter circuit for different frequency ranges in a 1992 documentation. The...
This circuit was found in a French magazine Toute LÉlectronique from 1978. Transistors are not...
This configuration is from a 1964 US documentation valid for any FET. The range of power voltages...