This circuit uses a high brightness LED to simulate a LASER. We found it in a 1991s PE Hobbyst Handbook. The components used are all common.
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...