You very well know that if distance between the two plates of capacitor is increased than its capacity reduces. Varactor diode Applications : Varactor diode is used in FM radio and TV receivers . The varactor diode was named because of the variable reactor or variable reactance or variable capacitor or variable capacitance property of these diodes. INTRODUCTION Varactor diode is a special type of PN junction diode, in which PN junction capacitance is controlled using reverse bias voltage. Varactor diode is also sometimes referred to as varicap diode, tuning diode, variable reactance diode, or variable capacitance diode. And ensure that varactor diode is not affected by the bias voltage or any other voltages in the circuit. A varactor diode works as follows: A basic diode consists of p-type and n-type materials which are considered as the conducting plates. The Varactor diodes belong to the family of semiconductor devices. Glass passivation is provided to create a shell that protects from corrosion. the voltage required to set the varactor diode capacitance. Consider the reverse biased mode of the diode, in which P-type region and N-type region are able to conduct and thus can be treated as two plates. These diodes have a similar structure as a p-n diode; the structure of a varactor diode is rather simple and illustrates its power as a component with nonlinear reactance. Varactor Diode is also known as Tuning Diode, Variable Reactance Diode, Varicap Diode or variable capacitance diode. When run with a AC small signal that have a high DC offset, it functions ver… The P-N Junction diode creates capacitor effect. It is also known as Varicap diode (Variable Capacitance).Applications of the Varactor Diode1) Voltage Controlled Oscillator2) Phase and Frequency Modulators3) RF Filters4) FM Receivers and other telecommunication receivers (For tuning)Important Specifications of the Varactor Diode:1) Capacitance Range2) Capacitance Ratio3) Reverse Current (Leakage current)4) Breakdown Voltage5) Quality FactorThis video will be helpful to everyone in understanding the varactor diode.#VaractorDiodeFollow my second channel: me on Facebook: me on Instagram: Credit: These devices are commonly used in communication systems. in general, it looks like a normal PN- junction diode in which one terminal is termed as the cathode and the other terminal is termed as anode. 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. Varactor diodes can be used as frequency modulators. These diodes have a p-n-n+ structure, where the applied voltage modulates the width of the depletion region between the p and n+ sides. A varactor diode is also called varicap diode. Let us discuss about the diode which is a two terminal electrical device. Your email address will not be published. The varactor diodes are small in size and hence, they are very light weight. The region of depletion is considered to be the dielectric. A varactor diode is a semiconductor diode whose junction capacitance varies linearly with applied voltage when the diode is reverse biased. Varactor diodes produces considerably less noise compared to other conventional diodes. The  oscillator can be enabled by turning the diode D1. The depletion region between the P-type and N-type regions can be considered as insulating dielectric. The obvious varactor diode considerations are: (a) Capacitance value (b) Voltage (c) Variation in capacitance with voltage. In the receive front end circuits, tracking filters may be essential. Digital Modulation Techniques: Electronics Engineering Notes pdf ppt, The Common-collector Amplifier Configuration Notes for Electronics Engineering 1st Year, Unity Gain Buffer/Unit Follower Notes for Electronics Engineering 1st Year, B.Tech./1Sem/Computer System and Programming in C, Fundamentals of Clamping Circuit Notes for Electronics Engineering 1st Year, Principle of Nicol Prism Engineering Physics B.Tech 1st Year, Zeolite Process for Water Softening and its Limitation Notes pdf ppt. This diode delivers the net variable capacitance in parallel resonant bandpass filter. Save my name, email, and website in this browser for the next time I comment. The CV characteristics of a typical Varactor diode and its symbols are shown in the following figure. The same thing can also be seen in the varactor diode. Varactor Diode. Fig1 Internal structure of Varactor diode. A voltage variable capacitance of a reverse biased junction can be termed as a Varactor diode. In general, electronic circuits can be built with a various electrical and electronic components like resistors, capacitors, diodes, transistors, integrated circuits, transformers, Thyristors, etc. The varactor diodes have the following significant characteristics: Varactor diodes finds large number of applications within the RF design arena and it is difficult to discuss about all the applications of varactor diodes or varicap diodes. The property of varying capacitance is utilized to achieve a change in the phase of an electrical circuit or in the frequency. The varactor diode can be tuned by applying tuning voltage or bias through an isolating series resistor R1. And, these are termed as abrupt varactor diodes, gallium arsenide varactor diodes, and hyper abrupt varactor diodes. ..... Our Mantra: Information is Opportunity. To understand the working principle of the varactor diode, we must know what is a capacitor and how can we change the capacitance. VARACTOR DIODE Nyamador Enock Seth University of Mines and Technology (UMaT), Tarkwa Computer Science and Engineering ‘14 Twitter: @enock4seth 2. Varactor Diode is a reverse biased p-n junction diode, whose capacitance can be varied electrically. Semiconductor diodes are the most common type of diode. If the varactor diode reverse voltage is increased, then the depletion region size increases. Varactor Diode is a reverse biased p-n junction diode, whose capacitance can be varied electrically. In microwave receiver LO, varactor diodes can be used as frequency multipliers. Variable capacitance leads to the origination of the varactor diode. “Never doubt that a small group of thoughtful, committed, citizens can change the world. In Fig b, the bias on D 1 is set by the voltage divider which is made up of R 1 and R 2. By watching this video, you will learn the following topics: What is Varactor Diode Working of the Varactor Diode Equivalent Circuit of the Varactor Diode Important Specifications of the Varactor Diode Applications of… for generation of FM wave. A few other important applications of varactor diodes can be listed as follows: Your email address will not be published. At the base we have heatsink to moderate the temperature of the diode and for cooling purpose. One side is seen from the positive while the other side is … Varactor diodes are again classified into various types based on the varactor diode junction properties. There is no useful purpose of varactor diode operated when it is operated in forward bias. It works on reverse biased mode. Required fields are marked *. 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 … The CV characteristics of a typical Varactor diode and its symbols are shown in the below figure. A Varactor Diode is a PN junction diode that is especially operated in reverse biased mode. Opposite to it if distance between the two plates is reduced than dielectric between them will also reduce and due to which its capacity increases. What is Varactor Diode? The function of the varactor diode is to use the principle of variable capacitance between PN junctions to make semiconductor devices, which are used as variable capacitors in high-frequency tuning and communication circuits. As a result these diodes are also referred to as varicaps, tuning diodes, voltage variable capacitor diodes, parametric diodes and variable capacitor diodes. the “low resistance” direction). Usually either R 1 or R 2 is made variable so that the center carrier frequency can be adjusted over a narrow range. The region of depletion is an important factor in determining the value of capacitance. Fig5. Increase in reverse bias of varactor diode increases the capacitance as shown in the figure below. Lets look into the construction, working of diode, characteristics and applications of varactor diode e use everywhere from the audio frequencies to the outer reaches of the extreme microwave frequencies. The varactor diode is a semiconductor device functions in a reverse bias and thus the capacitance of junction changes according to the varying applied voltage. The varactor diode is manufactured in such as way that it shows better transition capacitance property than the ordinary diodes. It is used for storing the charge. The junction capacitance of diodes varies with the amount of reverse bias. The V-I characteristics of the diode are non-linear and it permits the flow of current in only one di… It is a device whose capacitance changes with the variation in the applied reverse bias potential.It is also known as varicap or voltcap. When one of surfaces is connected to a positive voltage and the other to negative voltage, because of attraction between positive and negative carriers, positive charge accumulates on one surface and negative charge on the other. When investigating high performance varactor diodes for specific RF applications, the terms, abrupt and hyperabrupt varactor diodes will often be seen. It acts like variable capacitance in reverse bias operation. In this video, what is varactor diode, it's working, the applications and some important specifications are explained. Varactor Diode Definition: The diode whose internal capacitance varies with the variation of the reverse voltage such type of diode is known as the Varactor diode. Varactor diode is a semi-conductor device in which the junction capacitance can be varied as a function of the reverse bias of the diode. It is also known as Varicap diode (Variable Capacitance). The capacitance is controlled by applied voltage. Varactor diodes are used to vary the capacitance in variable resonant tank LC circuits. Similarly, if the varactor diode reverse voltage is decreased, then the depletion region size decreases or narrows. A varactor is a non-microphonic, comp;1ct, electronically var­ iable capacitor whose capacitance can be rea