Article
Article
Varactor
Article By:
Andersen, David R. Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa.
Last reviewed:January 2020
DOI:https://doi.org/10.1036/1097-8542.727800
A solid-state device which has a capacitance that varies with the voltage applied across it. The name varactor is a contraction of the words variable and reactor. Typically the device consists of a reverse-biased pn junction that has been doped to maximize the change in capacitive reactance for a given change in the applied bias voltage. The device has two primary applications: frequency-tuning of radio-frequency circuits including frequency-modulation (FM) transmitters and solid-state receivers, and nonlinear frequency conversion in parametric oscillators and amplifiers. See also: Capacitance; Frequency modulator; Parametric amplifier; Reactance
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