A varactor diode is a voltage controlled capacitor which finds its application in communication networks. Today you’ll learn its important concepts and basic working.
Besides varactor, they are sometimes referred as Varicaps or Tuning diodes.
List of Contents
Symbol and Physical look
The basic construction involves two pn regions. The doping is done so as to maximize the capacitance of depletion region. The nonconductive characteristics of depletion region cause it to behave as a dielectric. The p and n region behave like the capacitor plates.
The varactor always operates in reverse bias region. Let’s understand the working in detail:
- UHF Signals: Ultra high-frequency (300 MHz – 3 GHz) receivers utilize varactors to tune circuits.
- VHF Signals: Just like UHF, VHF receivers utilize them.
- Parallel resonant circuits: Used to adjust resonant frequency.