We found this circuit in the January 1978 issue of Radio Electronics magazine. The integrated circuit is from that time and is powered by a 9 V battery. The signal must be applied to an amplifier.
This circuit was found in a Radio Electronics from May 1965. FETs are from the time, but the...
This circuit can generate signals from 80 to 800 Hz with an amplitude of 0.3 V. We find it in a...
Because it uses TTL integrated circuits, this siren must be powered by 5 V or as indicated with D1 to...