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 activates a piezoelectric buzzer with an oscillator at the end of the programmed...
In this 1970s receiver, the coil has a primary with 100 turns and a secondary with 20 turns, both...
Found in old American documentation, this circuit is intended for the control of heating elements. The...