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 was found in a 90s Popular Electronics. The sensor can be any phototransistor. ...
This circuit is from an English magazine of 1974, but can still be assembled with the replacement of...
With this circuit any number of 4017 integrated circuits can be connected in series. The circuit is...