We found this circuit in a publication by General Electric in the 1980s. The transistors and the PUT are from that time. The control is done by a tachometer based on an optical coupler.
National Semiconductor suggests the figure circuit for stabilizing the peak value of an...
The general-purpose thermostat shown in the figure uses a high-resistive thermistor as a sensor....
This simple clock can be used to generate signals up to 100 kHz, depending on the crystal. We found...