Fig5. The diode is an electronic component that has 2 terminals positive terminal and negative terminal positive terminal called an anode and negative called cathode. As a result these diodes are also referred to as varicaps, tuning diodes, voltage variable capacitor diodes, parametric diodes and variable capacitor diodes. The contents of the lecture are; The Design and Basics of the Varactor Diode Characteristics and Parameters of Varactor Diode It is also known as varicap or voltcap.The word varicap is derived from the combination of word variable and capacitor. 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! Varactor diode is used in AFC circuits,self adjusting bridge circuits and adjustable bandpass filters; Varactor diode is used in tuning of LC resonant circuit in microwave frequency multipliers and in very low noise microwave parametric amplifiers. The varactor diode is usually . It works on the principle of Tunneling effect. This potential difference can alter the flow of majority carriers, so that the PN junction can be used as an opportunity for the diffusion of electrons and holes. Varactor Diode Modulator. The operation of a zener diode is like a normal diode in forward biased mode. Varactor diodes are also referred to as varicaps or tuning diodes and they are commonly used in communication systems. This will vary the junction capacitance of the varactor diode. C = Ae d where, C = the total junction capacitance. 2.2 Operating Principle of Diode . Working principle of manometer comprises of balancing a coloumn of liquid against the pressure to be measured. When a forward bias is applied, a large amount of current is generated, and the depletion region of the PN (positive and negative) junction becomes narrower. Lets look into the construction, working of diode, characteristics and applications of varactor diode Hello fellows, I hope you are doing great. Varactor Diode Working: To understand the working principle of the varactor diode, we must know what is a capacitor and how can we change the capacitance. If the PN-junction diode is in the forward bias, current flows through the diode. Its working principle is when the diode is reverse biased, small leakage currents pass through the diode, when the reverse voltage is further increased the leakage current also increases which are fast enough to break few covalent bonds within the junction these new charge carriers further breaks down the remaining covalent bonds causing huge leakage currents which may damage the diode forever. That means a large majority current flows through the device when the forward potential is applied to it. Varactor diodes are also referred to as varicaps or tuning diodes. The varactor diode is reverse biased by the negative dc source –V b. Hence, the voltage applied across the varactor diode varies in proportion with the modulating voltage. Principle. The operating principle of the photodiode is such that when the junction of this two-terminal semiconductor device is illuminated then the … So how does it work. It works on the principle of Photoelectric effect.. A voltage variable capacitance of a reverse biased junction can be termed as a Varactor diode. A tunnel diode or Esaki diode is a type of semiconductor that is capable of very fast operation, well into the microwave frequencyregion, made possible by the use of the quantum mechanical effect called tunneling.. Thus, is used in the construction of zener diode. Definition: Varactor Diode is a PN junction diode that is especially operated in reverse biased mode. The modulating AF voltage appears in series with the negative supply voltage. Varactor diodes are specially designed to take advantage of this characteristic and are used as Voltage Controlled capacitors rather than traditional diodes. for generation of FM wave. Varactor Diodes are a kind of special diodes. One side is seen from the positive while the other side is … The capacitor uses two surfaces that separate from the insulating dielectric. The boundary between each grain and its neighbour forms a diode junction, Just like a series connected diodes. 126 Principles of Electronics 7.1 Zener Diode A zener diode is a special type of diode that is designed to operate in the reverse breakdown region. Varactor diode Applications : Varactor diode is used in FM radio and TV receivers . What is a Schottky Diode? Diode Structure and Diode Symbol . The junction capacitance of diodes varies with the amount of reverse bias. Diode works on the principle of current displacement and drift in a semiconductor material when doped with an internal voltage difference also called barrier potential. These devices are commonly used in communication systems. The crystal diode is a pn junction formed by a p-type semiconductor and an n-type semiconductor, and a space charge layer is formed on both sides of the interface, and a self-built electric field is built. Working of PN Junction Diode If an external potential is applied to the terminals of PN junction, it will alter the potential between the P and N-regions. In today’s tutorial, we will have a look at Introduction to Varactor Diode. 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