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.
So This circuit was published in a 1982 English magazine, but can be easily assembled using BC548 for...
With this circuit it is possible to tune an AM signal using a 5k potentiometer (4k7). The circuit was...
This power source was found in a 1968 Electronics World. The transistors are from that time. The...