A varactor diode exploits the depletion region that forms at a P-N junction when reverse-biased. As the reverse voltage increases, the depletion region widens, moving the conductive regions further apart and decreasing the capacitance. This allows engineers to tune resonant circuits, oscillators, and RF filters simply by changing a DC control voltage.
Adjust the tuning voltage on the varactor to center the VCO at exactly 100 megahertz.
Also heard as
- varicap
- tuning diode
Related terms
Diode
A two-terminal semiconductor component that restricts electrical current to flow in only one direction.
VCO
A voltage-controlled oscillator is a circuit that changes its output frequency based on a DC input voltage.
Capacitor
A passive two-terminal component that stores electrical energy in an electric field.
Junction
The physical interface where two different materials or conductors meet.