This powerful sound emitter used in defense to intimidate people was found in a 90s Popular Electronics. The circuit produces a strong modulated tone of 3 kHz. The modulation is 10 Hz.
This circuit doubles the pulse rate produced by a digital TTL circuit. The circuit is from a 1976...
This alarm with automatic shutoff was found in the April 1975 Radio Electronics magazine. The...
This 12 V to 110 V inverter with 100 W was found in a 1977 Signetics manual. The transformer must...