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 an American documentation from the 90's. What it does is provide at the...
Found in old documentation, this circuit is tuned to pass signals below 245 Hz with a level of...
This series LED circuit was found in the February 1992 issue of Radio Electronics magazine. The...