This circuit was found in Motorola documentation from 1969. The transistors are from that time. The pulses are 200 ns with 500 mA. Observe the high supply voltage.
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...