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 passive tuned circuit was found in a 90s Popular Electronics. The coils must be according to the...
This circuit for model making was found in an English documentation. The SCR can be the TIC106, and...
The transistors of this symmetrical source from an old publication can be replaced by modern...