Found in a Popular Electronics from the 90s, this circuit generates signals from 2 Hz to 30 kHz in different bands. The circuit can be powered by voltages from 5 to 12 V, depending on the application.
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...