If both the emitter and collected are made negative with respect to the base, then the NPN transistor will operate in saturation region and works as an ON switch. If emitter is connected to positive terminal with respect to base and the collector is connected to negative with respect to base, then PNP transistor will operate in active region. The NPN transistor is said to be operated in active region if emitter is connected to negative terminal of battery with respect to base and the collector terminal is connected to positive terminal with respect to base. The switching time of PNP transistor is large. The switching time of NPN transistor is small. Switching speed of PNP transistor is low due to low drift velocity of holes. Switching of NPN transistor is faster due to high drift velocity of electrons. Holes are the minority charge carrier in NPN transistor.Įlectrons are the minority charge carriers in PNP transistor Holes are the majority charge carriers in PNP transistor. In PNP transistor, the direction of current is from emitter to collector.Įlectrons are the majority charge carriers in NPN transistor. In NPN transistor, current flows from collector region to emitter region. In PNP transistor, the emitter is P-type, base is N-type and collector is P-type. In NPN transistor, the emitter is N-type, base is P-type and collector is N-type. The following table highlights the key differences between NPN transistor and PNP transistor − DifferenceĪ type of transistor in which a thin layer of P-type semiconductor sandwiched between two layers of N-type semiconductor is known as NPN-transistor.Ī type of transistor in which a thin layer of N-type semiconductor sandwiched between two layers of P-type semiconductor is known as PNP transistor. Difference between NPN and PNP Transistor The circuit symbol of PNP transistor is shown in Figure-2. In a PNP transistor, the emitter and collector are made of P-type semiconductor material while the base is made of N-type material. When a thin layer of N-type semiconductor material is sandwiched between two layers of P-type semiconductor material, the resulting transistor is known as a PNP transistor. The symbol of the NPN transistor is shown in Figure-1. Hence, in case of NPN transistor, the emitter and collector are of N-type while the base is of P-type. What is NPN Transistor?Īn NPN transistor is the one in which two layers of N-type semiconductor material are separated by a thin layer of P-type semiconductor material. Read through this article to find out more about NPN transistor (BJT) and PNP transistor and the key differences between them. The three terminals are taken out from these three layers.īased on the arrangement of the semiconductor layers, the transistors are of two types as − A transistor (or bipolar junction transistor) is a three-terminal, three-layer and two-junction semiconductor device, used as the digital switch and amplifier in the electronic circuits.Ī transistor consists of three layers of P-type and N-type semiconductor materials and the name of these layers are emitter, base and collector.
0 Comments
Leave a Reply. |