Varactor diodes are reverse biased diodes. Varactor diodes are used along with reactance modulator to provide automatic frequency correction for an FM transmitter. 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… Varactor diode 1. 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. Lets look into the construction, working of diode, characteristics and applications of varactor diode These terms relate to the junction and hence the performance of the varactor diode - hyperabrupt diodes, as the name suggests, having a very sharp change in doping that produces a very abrupt junction - in fact it is a hyperabrupt junction! A varactor diode is a simple variable capacitor that allows oscillator circuits and other circuits to be easily tuned by applying a voltage. at a high rate of speed. These diodes begin conducting electricity only if a certain threshold voltage is present in the forward direction (i.e. Varactor diodes are also referred to as varicaps or tuning diodes. What is Varactor diode, How Varactor diode works, Electronic Devices & Circuits, Engineer Concepts. ..... Our Mantra: Information is Opportunity. The amount of charge that accumulates … A few other important applications of varactor diodes can be listed as follows: Your email address will not be published. Varactor diodes can be used as frequency modulators. These are special purpose diodes, also called a varicap diodes or tuning diodes or variable capacitance diodes, designed to work always in reverse bias state. When run with a AC small signal that have a high DC offset, it functions ver… Varactor diode is used in a mobile network system. Varactor Diode is a reverse biased p-n junction diode, whose capacitance can be varied electrically. In general, electronic circuits can be built with a various electrical and electronic components like resistors, capacitors, diodes, transistors, integrated circuits, transformers, Thyristors, etc. A Varactor Diode is a PN junction diode that is especially operated in reverse biased mode. It is used for storing the charge. In Fig b, the bias on D 1 is set by the voltage divider which is made up of R 1 and R 2. the voltage required to set the varactor diode capacitance. The varactor diode always works in reverse bias, and it is a voltage-dependent semiconductor device 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. These diodes are specially manufactured and optimized such that they enables a very high range of changes in capacitance. Varactor diodes produces considerably less noise compared to other conventional diodes. The varactor diode is one type of PN junction diode whose internal capacitance changes with the applied reverse bias voltage. You very well know that if distance between the two plates of capacitor is increased than its capacity reduces. Varactor diodes can be used as RF phase shifters. In microwave receiver LO, varactor diodes can be used as frequency multipliers. A voltage variable capacitance of a reverse biased junction can be termed as a Varactor diode. The varactor diode can be tuned by applying tuning voltage or bias through an isolating series resistor R1. Glass passivation is provided to create a shell that protects from corrosion. By watching this video, you will learn the following topics:0:21 What is Varactor Diode1:23 Working of the Varactor Diode5:19 Equivalent Circuit of the Varactor Diode6:28 Important Specifications of the Varactor Diode9:01 Applications of the Varactor DiodeWhat is Varactor Diode :The varactor diode is one type of PN junction diodes whose internal capacitance changes with the applied reverse bias voltage. Your email address will not be published. Varactor diodes are specially designed to take advantage of this characteristic and are used as Voltage Controlled capacitors rather than traditional diodes. The obvious varactor diode considerations are: (a) Capacitance value (b) Voltage (c) Variation in capacitance with voltage. A diode is effectively like a valve for an electrical 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. e use everywhere from the audio frequencies to the outer reaches of the extreme microwave frequencies. In this video, what is varactor diode, it's working, the applications and some important specifications are explained. The varactor diodes can be used to tune the filters. The  oscillator can be enabled by turning the diode D1. The symbol of varactor diode is shown in the figure. These devices are commonly used in communication systems. Definition of a Varactor Diode: “The term varactor is the shortened form of a variable reactor, which refers to the voltage-variable capacitance of a reverse-biased p-n junction.” Varactor diode is also known as a variable diode, vericap diode, tuning diode, variable reactance diode, or variable capacitance diode. 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:https://www.youtube.com/channel/UCGA2TO8ylVqFHpucwn_6JlwFollow me on Facebook:https://www.facebook.com/ALLABOUTELECRONICS/Follow me on Instagram:https://www.instagram.com/all_about.electronics/Music Credit:http://www.bensound.com/ Varactor diodes are again classified into various types based on the varactor diode junction properties. And, these are termed as abrupt varactor diodes, gallium arsenide varactor diodes, and hyper abrupt varactor diodes. As a result these diodes are also referred to as varicaps, tuning diodes, voltage variable capacitor diodes, parametric diodes and variable capacitor diodes. If the varactor diode reverse voltage is increased, then the depletion region size increases. Using this circuitry we can set the frequency through varying the voltage. 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. A varactor diode is a semiconductor diode whose junction capacitance varies linearly with applied voltage when the diode is reverse biased. Semiconductor diodes are the most common type of diode. The depletion region between the P-type and N-type regions can be considered as insulating dielectric. Even though the variable capacitance effect can be exhibited by the normal diodes (P-N junction diodes), but, varactor diodes are preferred for giving the desired capacitance changes as they are special types of diodes. And ensure that varactor diode is not affected by the bias voltage or any other voltages in the circuit. Fig5. A varactor diode is also called varicap diode. One side is seen from the positive while the other side is … The capacitor C1 is used to prevent the reverse bias for the varactor diode, also avoids the diode getting short-circuited through the inductor. Increase in reverse bias of varactor diode increases the capacitance as shown in the figure below. The region of depletion is considered to be the dielectric. The same thing can also be seen in the varactor diode. The CV characteristics of a typical Varactor diode and its symbols are shown in the below figure. Indeed, it is the only thing that ever has.” …………and we strongly believe on …, Theory of Varactor Diode Notes for Electronics Engineering 1st Year, on Theory of Varactor Diode Notes for Electronics Engineering 1st Year, Theory of Light Emitting Diodes Notes for Electronics Engineering, Tunnel diode Working principle and characteristics Notes for Electronics Engineering 1st Year. Varactor diode Applications : Varactor diode is used in FM radio and TV receivers . 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. Varactor Diode is also known as Tuning Diode, Variable Reactance Diode, Varicap Diode or variable capacitance diode. The junction capacitance depends on the applied voltage and junction design. The capacitance of D 1, of course, is controlled by two factors: a fixed dc bias and the modulating signal. To learn how a varactor diode works, you need to first understand the working principle of a variable capacitor:A capacitor consists of two conducting surfaces separated by a non-conducting dielectric medium (see figure below). The V-I characteristics of the diode are non-linear and it permits the flow of current in only one di… INTRODUCTION Varactor diode is a special type of PN junction diode, in which PN junction capacitance is controlled using reverse bias voltage. The word varicap is originated from the combination of word variable and capacitor. The region of depletion is an important factor in determining the value of capacitance. When varactor diode is connected with the resonant circuitry as shown in the below figure it operates like a variable capacitor. In this video, what is varactor diode, it's working, the applications and some important specifications are explained. VARACTOR DIODE Nyamador Enock Seth University of Mines and Technology (UMaT), Tarkwa Computer Science and Engineering ‘14 Twitter: @enock4seth 2. In this video tutorial, the presenter would be explaining about varactor diode, it’s working, and its applications. Metal contact is provided for the connection with battery. In the receive front end circuits, tracking filters may be essential. Required fields are marked *. It is a device whose capacitance changes with the variation in the applied reverse bias potential.It is also known as varicap or voltcap. The story begins with our tagline “ज्ञानम् परमं” (Knowledge is Supreme), which has been  subsequently becoming our brand. The Varactor diodes belong to the family of semiconductor devices. Working System Of Varactor Diode: How a Varactor Diode Works First one needs to understand the working principle of a changeable capacitor. 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. Applications of the Varactor Diode Usually, this is provided by microprocessor control through the digital to analog converter. The junction capacitance of diodes varies with the amount of reverse bias. The basic working of a varicap or a varactor diode can be understood with the following explanation: When a varactor or varicap diode is applied with a rising reverse bias potential, results in an increase in the depletion width of the device, which in turn causes its transition capacitance to decrease. 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. 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. To understand the working principle of the varactor diode, we must know what is a capacitor and how can we change the capacitance. 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. 2. The varactor diode modulator circuit is shown in Fig5. What is Varactor Diode? As a result these diodes are also referred to as varicaps, tuning diodes, voltage variable capacitor diodes, parametric diodes and variable capacitor diodes. Save my name, email, and website in this browser for the next time I comment. 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