This precision speed control was obtained in an Electronic Design from the 90's. The output final stage power transistors must be in accordance with the motor power.
This circuit is from a 1957 Raytheon transistor manual. The diode can be of general-purpose...
This converter for WWV time reference station signals was found at Popular Electronics. The 15 MHz...
This pulser, found in a 1979 publication, airs and closes the relay at a frequency determined by...