The voltage of the reverse bias is considerably smaller as compared to the reversed biased. The emitter-base region of the transistor is in forward biasing and the collector base region is connected in reverse bias. The collector is the thickest region and the base is the thinnest region of the NPN transistor. The NPN transistor consists two n-type semiconductor material which is separated by a thin layer of p-type material. Thus, complete emitter current flows through the collector circuit.Įmitter Current = Collector Current + Base Current The remaining hole reaches across the negatively biased collector-base region and collected by the collector due to which collector current develops. The hole in the p-type material combines with the n-type material hence constitute the base current. The emitter-base junction pushes the majority charge carrier toward the base, thus established the emitter current. The emitter-base junction of PNP is connected in forward biased while the collector-base junction is connected in reverse bias. The emitter and collector of PNP transistor are made up of p-type material and their base is made up of n-type material. It has three terminals emitter, base and collector. The PNP transistor has two blocks of p-type material and one block of n-type material. Originate because of varying position of holes.Ĭurrent develop because of the flow of holes.Ĭurrent develop because of the flow of electrons. Two blocks of p- types semiconductors are separated by one thin block of n-type semiconductor.ĭevelop because of varying position of electrons. Transistor in which two n-type layer are separated by one P-type layer This happens because the base of the NPN and PNP transistor is very thin and lightly doped. Sometimes when the voltage applied across the emitter the electrons cross the base junction and reach the collector region. The NPN and PNP transistor, both are made up of different material due to which the current develops in them also differs. The letter PNP and NPN show the voltage requires by the emitter, collector and base of the junction transistor. As the electrons are more mobile the NPN has high conduction. Mostly, the NPN transistor is used in the circuit because in NPN transistor the conduction current is mainly by electrons while in the PNP transistor the conduction current is because of the holes. It is the current controlling devices and mainly used for switching and amplifying the signal. The NPN and PNP both are the bipolar junction transistor.
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