This circuit with 10 MHz and 1.25 MHz TTL outputs was found in an American documentation from the 1980s. The used integrated circuit is uncommon today.
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...