Electronics Handbook/Components/Diodes/Variactor

This kind of diode conducts in both the forward and backward directions. When conducting in backward direction, the diode operates like a capacitor with capacitance in the picofarads.

The circuit symbol of variactor diode:
 * [[Image:Varicap symbol.svg|100px|left|Varicap schematic symbol]].

Operation
When negative voltage is applied to a variactor diode, the junction of the diode is widened and exhibits the capacitance of a capacitor.