Stepper Motor-Controlled Variable Capacitor

Stepper Motor-Controlled Variable Capacitor

The stepper-controlled variable capacitor is another approach to the same design problem of a controlled …read more

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Description

The stepper-controlled variable capacitor is another approach to the same design problem of a controlled capacitance. This version has a more limited scope as most mechanically variable capacitors are limited to values under 1 nF. However, the advantage is virtually unlimited bandwidth and precision control down to 1 pF steps (limited only by the resolution of the stepper motor. As with the Electronically Variable capacitor, this design lends itself to many uses, particularly in RF tank circuit tuning and load compensation circuits, where slight variations in the system or environment can detune the tank circuit. If larger capacitor values are desired, it would be possible to design special variable capacitors with specific liquid dielectrics to greatly increase the capacitance value. Also, paralleling multiple variable capacitors can increase the value as well. The whole system can be designed to mount directly to a PCB with all the required stepper motor control hardware on-board.