This is a typical variable capacitor. It has two sets of plates. One set is called the rotor and the other the stator. The rotor is connected to the knob outside the capacitor. The two sets of plates are close together but not touching.
Air is the dielectric in a variable capacitor.
As the capacitor is adjusted, the sets of plates become more or less meshed, increasing or decreasing the distance between the plates. As the plates become more meshed, capacitance increases. As the plates become less meshed, capacitance decreases. All Rights Reserved . No images, graphics, software, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders.