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.
Two operational are used on this triangular-rectangular oscillator suggested by Motorola in its...
This circuit from a Popular Electronics from the 90's can generate signals from 0.03 Hz to 3 kHz...
With 8 to 30 V power supply, the output power depends on both the voltage and the load. The...