This Vox or sound activated relay was found in an American documentation from 1975. Equivalent transistors can be used, and the SCR can be a TIC106. The relay is according to the supply voltage.
This double-T sine wave oscillator was found in the December 1995 issue of Electronics Now...
This circuit can function as an output shield for microcontrollers, being compatible with TTL...
This circuit uses the well-known 8038 to generate 3 waveform signals. Frequency bands are selected by...