Found in a 1964 Electronic Design, this circuit shows how to modulate a signal with a dynamic low impedance microphone. The circuit operates in the FM range (88 to 108 MHz).
This circuit triggers the LED when the monitored battery voltage drops below 9 V for 12 V...
We found this circuit in a Radio Electronics from January 1967. The SCR is already the C106, which...
This power source with silicon diodes at a time when valves were still used was found in Radio...