Varactor Diode are a semiconductor diode that is is utilised in RF tuning to circuits voltage-controlled variable capacitance. This type of diode can be used in a multitude of areas where a capacitance level needs to be controlled by a voltage.

How does a varactor diode work?

In order to achieve a specific variance in capacitance, this type of diode works with the different region types of a capacitor known as P-type and N-type. These types can be manipulated to give out higher depletion sizes or narrowed and decreased in size, this will give you the variable capacitance you wish out of the device.

Varactor diodes can also provide analogue control of voltage and can also alongside digitally generated voltage in microprocessors. an ADC can then be utilised to convert from analogue voltage to control the diode.

Where are varactor diodes used?

Varactor diodes have a range of application use such as;

Satellites
TV tuning
DVD devices
RF Tuning
Frequency synthesizers