This circuit was found in a 1965 Electronic Design. What it does is respond only to positive pulses (above zero volts) and can be used in automation systems.
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...