Varactor Diode

Varactor Diode & its application

Varactor

A varactor diode uses a p-n junction in reverse bias and has a structure such that the capacitance of the diode varies with the reverse voltage. A voltage controlled capacitance is useful for tuning applications. The capacitance is controlled by the method of doping in the depletion layer. Typical values are from tens to hundreds of picofarads.

Application of Varactor Diode

Following are the varactor diode applications:
1.  It is used in variable resonant tank LC circuit. Here C part is varied using varactor diode.
2.   AFC(Automatic Frequency Control) where in varactor diode is used to set LO signal.
3.   Varactor is used as frequency modulator.
4.  It is used as frequency multiplier in microwave receiver LO. 5.  It is used as RF phase shifter