This circuit is from American documentation from the 1980s. The circuit can make use of any common NPN transistor and the power comes from two small batteries.
This 1987 circuit has a very interesting concept. It powers a second set of rhythmic lights from...
This circuit with reed sensors is very simple, feeding a 12 V siren when triggered. The circuit has a...
The signal from this transmitter is injected into a cable that you want to follow along a...