What is a varicap diode used for?
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.
What is varactor diode modulator?
Varactor diode modulator is the direct method of FM generation wherein the carrier frequency is directly varied by the modulating signal. A varactor diode is a semiconductor diode whose junction capacitance varies linearly with applied voltage when the diode is reverse biased.
Who invented varicap?
The varicap was developed by the Pacific Semiconductor subsidiary of the Ramo Wooldridge Corporation who received a patent for the device in June 1961. The device name was also trademarked as the “Varicap” by TRW Semiconductors, the successor to Pacific Semiconductors, in October 1967.
What is the microwave application of a varactor?
A few of the main applications of Varactor diodes can be listed below: These diodes can be used as frequency modulators and RF phase shifters. These diodes can be used as frequency multipliers in microwave receivers. These diodes are used to change the capacitance in-tank LC circuits.
Why is a varicap diode operated in reverse bias?
Operation of Varactor Diode The function of the varactor diode is to store charges, so it is always operated in reverse bias condition. When a forward bias voltage is applied, the electric current flows, as a result, the depletion region becomes negligible, which is undesirable.
Where is photodiode used?
Photodiodes are used in consumer electronics devices such as compact disc players, smoke detectors, medical devices and the receivers for infrared remote control devices used to control equipment from televisions to air conditioners. For many applications either photodiodes or photoconductors may be used.
How does a varactor diode work?
A varactor diode is designed to store electric charge not to conduct electric current. So varactor diode should always be operated in reverse bias. When a reverse bias voltage is applied, the electrons from n-region and holes from p-region moves away from the junction.
What is the modulation index of FM?
In FM (Frequency Modulation), the modulation index is defined as the ratio of frequency deviation to the modulating frequency. Mathematically, this is defined as: m f = Δ f f m.
What is apin diode?
A PIN diode is a diode with a wide, undoped intrinsic semiconductor region between a p-type semiconductor and an n-type semiconductor region. The p-type and n-type regions are typically heavily doped because they are used for ohmic contacts.
How does varactor diode work?
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.