Variable Capacitors for High Accuracy Tuning / 14/844,225

Thursday, September 3, 2015

Improved interdigital parallel plate rotary capacitors to be used in automatic MHz range tuners have a grounding technique based on bronze sliding contact to effectively and continuously lead to the ground terminal the rotating comb-like blades of the capacitor and (optional) damping resistors inserted between the sliding contact and the ground terminal. The resistors reduce the high Q of the series resonance of the capacitor with the fringe lead inductance. Tuning sensitivity is reduced and tuning accuracy and repeatability are increased.