What is varactor diode and its application?
Varactor or varicap diodes are used mainly in radio frequency or RF circuits to provide voltage controlled variable capacitance. These electronic componenta can be used in a whole variety of ways where a capacitance level needs to be controlled by a voltage.
Which is the principal characteristic of a varactor diode?
Characteristics of Varactor Diode These diodes significantly generate less noise compared to other diodes. The cost of these diodes is available at lower and more reliable also. These diodes are very small in size and very lightweight. There is no use when it is operated in forwarding bias.
What is the meaning of varactor diode?
Electronic symbol. In electronics, a varicap diode, varactor diode, variable capacitance diode, variable reactance diode or tuning diode is a type of diode designed to exploit the voltage-dependent capacitance of a reverse-biased p–n junction.
What is the construction of a varactor diode?
A Varactor Diode consists of p-type and n-type semiconductor layers sandwiched together, with the n-type layer attached to a mesa (table-shaped) structure. A gold plated molybdenum stud is connected to n-type layer via the mesa structure and it acts as cathode terminal.
How varactor diode is different from pn junction diode?
In a normal PN junction diode, doping impurities are usually dispersed equally throughout the material. Varactor diode doped with a very small quantity of impurities near the junction and impurity concentration increases moving away from the junction.
How does a varactor diode work?
Varactor Diode. Definition: Varactor diode is the one which works on the principle of variation in capacitance by changing the width of the depletion region of P-N junction. The P-N Junction diode creates capacitor effect. The capacitance is controlled by applied voltage. It works on reverse biased mode.
How do you increase the capacitance of a varactor diode?
So if we need to increase the capacitance of a varactor diode, the reverse bias voltage should be decreased. It causes the width of the depletion layer to decrease, resulting in higher capacitance. Similarly, increasing the reverse bias voltage should decrease the capacitance.
What is the working principle of led?
Working Principle of LED The LED stands for light-emitting diode and in the below figure, you can see the symbol of LED. The working of LED is very simple when led is in forward biasing conditions the electrons existing in N side of diode cross the PN junction and enter in the P region combine with the holes existing in that region and emit light.
What happens when forward bias voltage is applied to a diode?
When a forward bias voltage is applied, the electric current flows, as a result, the depletion region becomes negligible, which is undesirable. The junction capacitance of a p-n junction diode is inversely proportional to the width of the depletion layer.