Variable Capacitors - definition

A Variable Capacitor is an Instrumentation component whose capacitance electrical value can be adjusted within a certain range by the user or automatically, depending on the design used. Unlike fixed capacitors, whose capacitance value is invariable, variable capacitors allow the circuit parameters to be adjusted without having to replace the component.

The basic principle of a variable capacitor is based on the same physical phenomena as in fixed capacitors - the accumulation and release of electrical charge between two electrodes separated by dielectric. In order to change the capacitance, one of the factors affecting its value is modified: the surface area of the overlapping electrodes, the distance between them or the properties of the dielectric. Capacitors with rotating electrodes, in which capacitance is adjusted by changing the angle or offset of a set of moving and stationary metal plates, are the most common solution. Capacitors with variable dielectric thickness or using materials with variable electrical permeability also exist.

Variable Capacitors are mainly used in tuned circuits such as resonant circuits, bandpass filters, frequency generators or radio receivers. In modern electronic systems, they are increasingly being replaced by their digital counterparts or circuits with adjustable characteristics using active components. Nevertheless, in analogue applications and where precise, continuous capacitance regulation is required, variable capacitors remain an essential building block.

Transfer Multisort Elektronik (TME) is one of the world’s largest global distributors of electronic components, electrotechnical parts, workshop equipment, and industrial automation. The catalog includes over 1,500,000 products from 1,300 leading manufacturers. TME’s modern logistics centers in Łódź and Rzgów (Poland), with a combined area of over 40,000 m², ship nearly 6,000 packages daily to customers in more than 150 countries.

TME also invests in the development of knowledge and skills of young engineers and electronics enthusiasts through the TME Education project, and supports the tech community by organizing the TechMasterEvent series, promoting innovation and experience exchange.