Suggested by Sprague in the 90's documentation, this circuit applies to AC motors. The documentation does not indicate the maximum engine power that can be controlled.
The oscillator shown generates a rectangular output signal at a frequency of 5 MHz, determined by the...
Found in a Popular Electronics - January/February 1969 this circuit was intended to increase the...
Found in a radio amateur magazine of the 1980s, this circuit uses components that can still be...