This small tone generator was found in the November 1987 issue of Radio Electronics magazine. The phototransistor is common and controls the sounds generated. The basic frequency is given by C1.
Any FET can be used on this 80's circuit. Power can be supplied with batteries. The output is...
An audio amplifier of good power, and great sensitivity; a simple tuning step and a detecting...
The integrated circuits used in this circuit are from the 70s and are therefore no longer common in...