This very simple circuit uses a phototransistor and a very sensitive relay (reed type) being used over short distances with a lens system. The circuit is from a 1967 Japanese publication.
We found this circuit in a 1973 documentation. The null adjustment trimpot is 10k. The circuit can be...
This commercial transistor radio was manufactured in Japan in the 1960s. The circuit has only 3...
This FM transmitter was described in the Radio Electronics magazine of June 1963. It operates in...