This circuit with SCR is from a Radio Electronics magazine from September 1965. It is a commercial control from Heathkit for controlling universal motors.
This circuit that has a response from 10 Hz to 700 kHz was found in Philips documentation from 1968. Dual...
This circuit is from old documentation, using a component that cannot be found easily today. The...
This circuit was found in an ancient American documentation. The integrated circuit is of the time...