Chapter 13. variable capacitor
What It Does
A variable capacitor allows adjustment of capacitance in much the same way that a potentiometer allows adjustment of resistance.
Large variable capacitors were developed primarily to tune radio receivers, in which they were known as tuning capacitors. Cheaper, simpler, and more reliable substitutes gradually displaced them, beginning in the 1970s. Today, they are still used in semiconductor fabrication, in RF plastic welding equipment, in surgical and dental tools, and in ham radio equipment.
Small trimmer capacitors ...