This circuit was found in the July 1995 issue of Electronics Now magazine. The integrated circuit is an RCA-era type. The triac must be equipped with a heat sink.
The circuit shown in the figure, activates a bar of 4 LEDs with an audio signal applied to its...
This sophisticated RPM counter circuit with discrete integrated circuits was obtained in a 1993...
This circuit was found in documentation from the 90s. Its purpose is to dial a programmed number...