Holes are relatively heavier and have a slower speed than electrons. The channel in P-channel JFET is made of P-type material and holes are the charge carriers responsible for current flow. Applying a negative V GS creates a depletion region that reduces the channel width. The recovery time of electrons is fast thus N-channel JFET has a fast switching speed.Īt zero gate voltage, it will conduct current between its source and drain as there is a channel.

The charge carriers responsible for current flow are electrons. Therefore, JFET can be divided intoĪn N-channel JFET’s channel is made of N-type semiconductor material hence the name. The channel can be made from either P-type or N-type semiconductor material.

JFET (Junction FET) and MOSFET (Metal Oxide Semiconductor FET). There are two types of FET transistor i.e. Therefore, its switching speed is very fast and it can be used for very high-frequency applications. Since the FET utilize only one type of charge carrier either electrons or holes, the recovery time is very fast. Consequently, it has very low energy consumption and high efficiency. Since the input (gate) is reversed biased, the input impedance of FET is very high in the range of 100M ohm which is why there is no input or gate current. Therefore, it is a voltage-controlled device. Such operation mode is called depletion mode. While applying a reverse V GS decreases the channel length and the current I D. Applying a forward gate to source voltage V GS increases the channel width and thus the drain current I D. The width of the channel is controlled by the voltage applied at its gate. This is because the transistor transfers its resistance from one end to another end based on the input signal.Ī transistor is mainly classified into two types: The word “ Transistor” is the combination of two words “Trans” for “ Transfer” and “istor” for “ Res istor”. A small current or voltage at its input can be used to control very high output voltage or current.

Heterojunction Bipolar Transistor (HBT)Ī transistor is a three-terminal semiconductor device that is used for the switching or amplification of a signal.

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