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 was obtained in the 1990 Motorola Linear Databook. The circuit uses a 139 series...
We found this circuit in an English publication from 1980, but it can be assembled with BC548...
The circuit shown in the figure has a very high switching speed and can work with currents up to...