This circuit is from a 1924 book by Gernsback. The receiver uses two tubes and listens to headphones. Power is supplied by battery with the indicated voltages.
This 1/2 hertz high selectivity filter was found in the December 1990 issue of Radio Electronics...
The two power steps below are intended for use with the SAA1027 stepper motor control but can be...
This interesting circuit, found in a 1986 publication, includes a powerful audio amplifier. Being...