Scott Newman
Voltronics Corporation, 100 Ford Road, Denville, NJ 07834; (973) 586-8585, FAX: (973) 586-3405, Internet: www.voltronicscorp.com.

Capacitors are fundamental circuit elements used in resonant circuits, including filters and oscillators. Although single-valued or "fixed" capacitors are used in the majority of electrical circuits, at times it is desirable to build a variable range of capacitance into a circuit for tuning purposes. A trimmer capacitor provides that flexibility, making it possible, for example, to move the center frequency of a filter that may have shifted due to vibration or other environmental effects or to overcome the effects of aging in a quartz crystal oscillator.

In conjunction with computer-aided-engineering (CAE) software modeling tools, trimmer capacitors provide a tuning "window" that allows a designer to "tweak" the imperfect capacitance-value predictions made by a CAE simulator when it is optimizing, for example, the capacitor and inductor values of a filter for maximum rejection at a given center frequency.

Modern trimmer capacitors are available with a wide range of dielectric types, including air, polytetrafluroethylene (PTFE), glass, and sapphire, as well as a variety of package styles, including housings suited for printed-circuit-board (PCB) mounting and surface-mount applications. Trimmer capacitors are manufactured and tested according to different applications, in commercial, industrial, and military circuits, each with its own specified temperature range and environmental requirements. In addition, Voltronics offers both standard and non-magnetic trimmer capacitors, designed and manufactured without magnetic materials for use in critical industrial and medical applications, such as magnetic resonance imaging (MRI) systems.

To understand more about selecting a trimmer capacitor for a specific application, please turn to the article "Specifying A Trimmer Capacitor" in our literature section. Or feel free to call our Sales Department for more information on our trimmer capacitors.