It has three terminals Gate (G), Drain (D) and Source (S). JFET or Junction Field Effect Transistor is a type of FET having one PN junction between the gate and channel.

Difference Between NPN and PNP Transistor.Difference Between BJT and FET Transistors.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. Therefore, the drain and source terminals are interchangeable. However, the drain terminal is the one having more positive voltage. The drain and source are made of the same semiconductor material. The channel refers to the path for the flow of current. Based on its construction, FET has a channel between its drain and source. The three terminals of FET are Drain (D), Gate (G) and Source (S). the current flow only due to majority charge carriers that is either electrons or holes.

Related Post : What is PNP Transistor? Construction, Working & ApplicationsįET or field-effect transistor is a type of transistor that uses the electric field or voltage to control the current flow.

Therefore the total current I C is emitter current minus base current

In the symbol of PNP transistor, the arrowhead pointing inwards represents the direction of the current flowing inside the emitter toward the base and collector. Since the majority carriers are holes, the recovery time of the PNP transistor is comparatively high thus it has low switching speed than the NPN transistor. The output impedance is very high due to collector-emitter reverse bias. Since its base-emitter junction or input is forward biased, the input impedance is very low. This current is directly proportional to the base current. By connecting the base-collector junction in reverse and base-emitter junction in forward bias allows the flow of current between emitter and collector. It means it uses the input current at its base terminal to control the output current or collector current. The emitter and collector are both heavily doped with the emitter comparatively heavily doped than the collector.īJT is a current controlled device. The base is the most lightly doped layer of all. The base is the middle layer sandwiched between Emitter and Collector. Each terminal is connected with each layer of the transistor. While the junction refers to the boundary between two different semiconductor materials usually known as PN junction.Ī BJT is made of three alternating layers of P-type and N-type semiconductor materials having two PN junctions. Bipolar means that it uses both types of charge carriers i.e. 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:īJT or Bipolar Junction Transistor is a type of transistor that is bipolar and has a junction. 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.

Power bjt transistor