This circuit was found I a 1965 Radio Schack documentation. The transistors are from that time, admitting equivalents. The transformer has 500 ohm primary and secondary depending on the speaker.
This 0.5 Hz filter was found in the December 1990 issue of Radio Electronics magazine. The power...
This circuit was obtained in the SGS manual of linear integrated circuits of 1982. The maximum...
This circuit allows linear brightness control of an LED from an input voltage. The power supply must...