Frequency multipliers. 14.37. In tunnel diode, the p-type semiconductor act as an anode and the n-type semiconductor act as a cathode. Now let’s find out how we can vary the capacitance of a varactor diode. Schematic symbol for a varactor diode and capacitance equation. Varactor Diodes: Varactor Diodes are used as variable capacitors. Varactor diode 1. The varactor diode symbol consists of the capacitor symbol at one end of the diode that represents the variable capacitor characteristics of the varactor diodes. It is used as an electrically controlled capacitance (note that the schematic symbol appears as a hybrid of normal diode and capacitor symbols). Its symbol is that of an ordinary diode, with a capacitor symbol next to it. And this is the schematic symbol for a Schottky diode. Working principle of varactor diode: At this point the junction capacitance be influenced by on the instigated voltage and the design parameter of the junction. Photo Diode, Laser Diode, Varector, SCR, Shockley Diode Symbol. While Varactor diodes are designed to optimize the effect of junction capacitance. Each of these diode circuit symbols incorporates the basic diode format, but is modified to indicate the different function. ConceptDraw. Schottky diodes are designed to minimize the junction capacitance. Varactor Diode Symbol. It is well known that the operation of the p-n junction depends on the bias applied which can be either forward or reverse in characteristic. This diode also has anode and cathode like PN junction diode. The varactor diode is one type of PN junction diode whose internal capacitance changes with the applied reverse bias voltage. The following figure shows the symbol of Varactor diode. Even though the o/p of the variable capacitance can be exhibited by the normal PN-junction diodes. It is operated in reverse bias condition. The schematics symbol of the Varactor diode is as shown in the following image: Construction of the Varactor Diode: The Varactor Diode is composed of the PN junction thus the basic construction of the Varicap is similar to that of the simple PN junction diode but the PN junction in Varactor diode is optimized for variable capacitance. A variable voltage is applied across it in such a way that the diode is reverse-biased.This means that virtually no current passes through it – the positive voltage is applied to the cathode. These diodes are also called as transil diode or thyrectors. Varactor Diode is a reverse biased p-n junction diode, whose capacitance can be varied electrically. The symbol of varactor diode is also shown in the resultant figure. A number of schematic symbols are used to represent a Varactor Diode in circuit diagrams. Then we have a Schottky diode. Varactor Diode Symbol: A specially processed junction diode that assumes the properties of a variable capacitor (about 5 —250 pf) when its dc reverse voltage is varied is called a Varactor Diode Symbol shown in Fig. These types of diodes are used as voltage-controlled capacitors. Topic: Varactor Diode Name: Abdul Mohiz Roll No: CS-15-41 2. o A varactor is a diode that always works /operates in reverse bias and is doped to maximize the inherent capacitance of depletion region. The P-N Junction diode creates capacitor effect.The capacitance is controlled by applied voltage. But this varactor diode is a special classification of diode which operates well with reverse voltages. Of them, the three most popular representations are shown below: Among these three symbols of a Varactor Diode, the second symbol is more frequently used. You can see that the symbol of this diode is alike to a normal diode. A P-N junction diode which acts as a variable capacitor by changing reverse bias is known as a Varactor Diode.. Word Varactor is given to it due to its property of varying capacitance. Its P-N junction capacitance can be altered with an applied reverse voltage. 434 19. They are manufactured with gallium arsenide. Some of the major types of diode include the PN junction, Schottky, varactor, Zener or avalanche reference diode, photo diode, light emitting diode. Zener Diode Symbol, Schottky Diode Symbol, Backward Diode, Tunnel Diode Symbol, PIN Diode, LED Symbol. Figure 1 shows how a varactor diode might be connected to demonstrate its operation. The junction is made of gold or aluminum and n-type silicon. FM transmitters and Phase locked loops in radio, television sets and cellular telephone. These diodes are also called as variceal diodes. 11. Figure \(\PageIndex{11}\): Varactor diode schematic symbol. Varactor Diode Applications. do somebody know . Varactor diode is a unique type of diode. 14.) Figure 1 shows the symbol for a varactor diode and its equivalent electrical model at high frequencies. It is also known as Varicap diode (Variable Capacitance). Voltage Controlled Oscillator; Phase and Frequency Modulators; When this diode is operated in Reverse biased mode the width of the depletion region can be controlled which makes it act as a capacitor. A Varactor Diode may also be known as a Varicap or the term VVC. Its capacitance varies by changing the reverse voltage. Nov 20, 2018 #6 michael1978. Varactor diode can only be operated in reverse bias.It acts like variable capacitance in reverse bias operation. This page describes varactor diode basics and varactor diode applications.The link to varactor diode calculator,PIN diode,Tunnel diode and GUNN diode basics and applications are also mentioned.. Varactor diode is one of the many microwave semiconductor devices in use today.. 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