This variable frequency oscillator for radio transmission covers the range from 1.6 MHz to 20 MHz, depending only on the coil used. The circuit is very stable and can be used in amateur equipment.
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...