411 REFERENCE · Wikibooks
Electronics Handbook/Components/Diodes/Variactor
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
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:
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.