Varactor diodes or Varicap diodes are semiconductor devices that are widely used in the electronics industry. They are also used within the RF design arena. In this article, we will learn about the characteristics and applications of the varactor diode.
Varactor diode is a type of diode whose internal capacitance varies with respect to the reverse voltage. It always works in reverse bias conditions and is a voltage-dependent semiconductor device. Several names know varactor diode as Varicap, Voltcap, Voltage variable capacitance, or Tunning diode.
From the diagram given below, it is evident that the symbol of the varactor diode is similar to that of the PN-junction diode. The diode has two terminals: anode and cathode. One end of the symbol consists of the diode, and the other has two parallel lines representing the capacitor’s conductive plates. The gap between the plates shows their dielectric.
Varactor diodes are mostly operated under reverse bias conditions; therefore, there is no conduction. They are voltage-controlled capacitors and are sometimes known as varicap diodes, although the word varactor is widely used.
Variable capacitance effect is shown by normal diodes, but varactor diodes are preferred for providing the required capacitance changes. The diodes are uniquely optimized and manufactured to enable high-range changes in capacitance. Varactor diodes are categorized based on the properties of the diode junction.
Some applications of varactor diode are given in the points mentioned below.
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