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 found in Linear Technology documentation from the 90s. The circuit uses the...
This active crossover filter was obtained from the component manual used. Below is the performance...
At dusk this circuit triggers a relay switching lamps. The circuit can be powered from 6 to 12 V...