A capacitor is an electrical device characterized by its capacity to store an electrical charge. A trimming capacitor is a type of capacitor that has variable capacitance and allows for fine adjustments. While the capacitance of a trimming capacitor is set during the initial build of an application, these variable capacitors may be intentionally changed mechanically or electronically.
In order to change the capacitance of a trimming capacitor, it is important to understand their physical make up. Trimming capacitors contain two conductive plates and a dielectric. The two conductive plates surround the dielectric. By moving, shifting or alternating one of the conductive plates; any desired capacitance within the physical dimensions may be achieved.
Trimming capacitors are often used when size and performance is critical. Often time, they are found in LC Circuits, which are used for generating or identifying a particular frequency. Electronic devices, such as radio equipment, are examples of applications where you may find trimming capacitors.