Found in a 1949 Radio Electronics, this 4-tube circuit was fed directly from the mains with a half-wave rectifier.
Any power MOSFET that supports the current of the controlled stepper motor can be used on this...
This QST circuit generates 4 frequency signals according to the crystals used. Transistors admit...
This circuit was found in a Popular Electronics of the 1990s. The sensor is a rotating mechanical...