Application of Varactor Diode

What is a Varactor Diode?

A varactor diode, also known as a Varicap or volt-cap, is a type of PN junction diode primarily utilized in the reverse-biased mode. It is a device whose capacitance varies with the variation in the applied reverse bias potential. The term “Varicap” originates from the fusion of the words “variable” and “capacitor.”...

Construction of Varactor Diode

The construction of a varactor diode is similar to a regular p-n junction diode, with some additional characteristics. These are added to ensure it shows characteristics of variable capacitance....

Working of Varactor diode

An important point to note is that varactor diode works in Reverse biased configuration....

Varactor Diode in Tuning Circuitvaractor diode in tuning circuit

In this circuit...

Characteristic Curve of Varactor DiodeCharacteristics curve of varactor diode

The graph shows the non-linear relationship between capacitance and voltage applied to diode. It is known that capacitance and width have an inverse relationship which means that as the width of the depletion region increases with the reverse voltage, the capacitance decreases (i.e. varies inversely as shown in the graph)....

Application of Varactor Diode

Voltage-Controlled Oscillators(VCOs): Varactor Diodes are used in VCOs. VCOs are used in Phase-locked Loops and Communication Systems. By Varying the Voltage Across the Varactor Diode, the Capacitance Changes which leads to change of the Frequency in the Oscillator.Frequency Modulation Tunning in Radios: The Varactor Diodes are also used in the RF Circuits. By Varying the Voltage Across the Varactor Diode we can adjust the resonance Frequency of the tuned Circuit which we allow the tuning in FM radios.Phase Shifters: Varactor Diodes are also Implemented in Phase array Antennas. By Varying the Capacitance in the Certain part of the Antenna Array can lead to Controlling of the phase of the Emitted Signal Which can be used for beam Steering and Shaping.Voltage-Controlled Filters: Varactor Diodes are used in Voltage Controlled Bandpass or lowpass Filters. The Cutoff Frequency of the Filter can be Adjusted by Varying the Voltage across the varactor diode....

Advantages

Some common applications of varactor diode include:-...

Disadvantages

Mode-specific: The designing of these diodes is done to operate them in reverse-bias hence they are not useful in forward bias.Non-linear behaviour: The major drawback of this diode is its non-linear capacitance-voltage relation which can result in distortion un many appliances.Sensitive: The capacitance of this diode is largely affected by temperature variations thereby making it temperature-sensitive....

Conclusion

In Conclusion, the varactor diode is PN Junction Diode which is Primarily Used for Reverse Bias for Variable Capacitance properties. The Characteristics Curve Shows a Non-Linear Relationship Between Capacitance and Voltage. Despite being Economically Affordable, Varactor Diodes have Limitations, Such as Mode-Specific Operations and Sensitive to temperature Variation. So In this article we have Gone Through Varactor Diode, we have seen all its working with Applications, Advantages and FAQs....

FAQs on Varactor Diode

1. What are the different types of diodes?...