This 4093 IC continuity tester was found in the November 1986 Radio Electronics magazine. The circuit powers a ceramic buzzer with a frequency setting.
This simple electronic toy organ produces an interesting sound, which can be used by the most...
This SCR circuit was found in an American 1980s documentation. The circuit is still current,...
The sensor of this circuit can be any phototransistor and the SCR can be the TIC106. The circuit and...