This circuit was found in an American 1980s documentation. The transistorized step is the receiver's last IF and the diode is the receiver's existing detector.
This sweep generator or current-controlled oscillator was found in Popular Electronics from...
This dimmer, from an old publication, can use almost any triac and in shooting a neon lamp. The...
This circuit was found in an English technical documentation from 1976. The supply can be done...