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.
The output voltage is adjusted by the trimpot. The power transistor mist be mounted on a heatsink. The 3.9...
Originally, this circuit is from an English magazine, but I found it in Argentina's Radio Chassis...
The previously mentioned versions of monostable multivibrators in this section are not...