Suggested for the control of photographic enlargers, this 1967 General Electric circuit uses still common components. The circuit directly controls a lamp for exposing negatives.
This three-phase control for induction motor was found in a Motorola documentation from 1968. The...
We find this circuit in an American 1980s documentation. The unijunction transistor may be the...
This circuit was found in a 1966 EEE. Transistors support modern equivalents and the waveforms are...