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.
We found this circuit in a 1968 Electronics World. The potentiometer should be set to trigger the SCR...
This circuit generates signals from 50kHz to 10MHz, depending on the crystal used. The transistors can be...
This simple light relay circuit was found in a 1988 documentation. The base is the operational 741 which has...