This circuit was found in the December 1976 issue of Radio Electronics magazine. The circuit includes a powerful pulsating siren. It is activated by courtesy light switches and other sensors.
This circuit with RIAA equalization is from 1985 US documentation. The circuit has a flat response...
Found in Popular Electronics from the 1980s, this circuit can use more modern transistors such as...
This circuit appears in other articles in this section, but it is very interesting. It is a...