With a 120 ohms resistor this circuit can also be used as a shield for 3.3 V output voltages. The circuit uses an opto-diac enabling the control of triacs connected to the power grid with total isolation.
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...