This circuit was found in a Popular Electronics from the 90s. It is intended to power the filament of old radio valves in recovery works. It is indicated for tubes that use 5 V of filament.
With the precision given by the crystal this circuit provides signals of several frequencies for the...
) This two-transistor circuit features excellent gain operating with low impedance microphones. The...
This circuit was obtained from an American documentation from the 80s. Integrated circuits are...