This circuit was obtained from the April 1978 Radio Electronics magazine. The other circuit is a PLL of the time. The power supply must be 15 V symmetrical.
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...