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 purpose of this circuit is to turn off a lamp after a few seconds or minutes depending on the...
The frequency of the signal produced by this oscillator depends on the amount of light falling...
This setting applies to virtually any photo transistor and any operational amplifier. The power...