This highly sensitive light sensor was found in a 1970 General Electric documentation. The circuit can use the 2N2646 for the UJT and the phototransistor can be of any type.
This untuned (aperiodic) amplifier circuit was found in the August 1974 Radio Electronics...
This circuit was found in an American 1980s documentation. The integrated circuit used is uncommon...
Found in a 1964 Electronic Design, this circuit makes use of period components. The components are from...