This is the commercial circuit for the TRF-44 amplifier sold in Japan in the 1960s. The circuit provides a few hundred milliwatts and is intended to be used as small, battery-powered turntables.
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...