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 source was found in Philips' 60s documentation. The transistors are from the era and the...
This circuit is the digital indicator for the previous circuit and can be used with similar...
Found in a 90s Electronic Design, this circuit operates with Maxim components of the time. The...