Found in Electronics Now, this circuit generates signals for testing like a signal injector. The frequency will be between 20 Hz and 10 kHz with the indicated components.
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...