This circuit was featured in the March 1972 issue of Radio Electronics magazine. It adds automatic gain control to turntables by acting directly on the cartridge signal.
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...