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 obtained in the manual of the used integrated circuit. Equivalents may be used...
The UVTRON tube is an ultraviolet radiation sensor. In this circuit from Radio Electronics from...
This circuit was suggested by Popular Elecronics from the 90's. The circuit has high input...