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The transistor in which one p-type material is placed between two n-type materials is known as NPN transistor. The NPN transistor amplifies the weak signal enter into the base and produces strong amplify signals at the collector end. In NPN transistor, the direction of movement of an electron is from the emitter to collector region due to which the current constitutes in the transistor. Such type of transistor is mostly used in the circuit because their majority charge carriers are electrons which have high mobility as compared to holes.

NPN transistor  are mainly used in switching application Used in amplifying circuit application Used in the Darlington pair circuits to amplify weak signals. NPN transistor are used in the application where there is a need to sink a current. It is used as a switch, as an amplifier.

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hello aspirant..,

NPN Transistor. Definition: The transistor in which one p-type material is placed between two n-type materials is known as NPN transistor. The NPN transistor amplifies the weak signal enter into the base and produces strong amplify signals at the collector end. NPN transistors have electron as majority carrier and so NPN is preferred because of faster mobility of electrons. NPN is most suitable for negative ground system. Common Emitter configuration is most widely used transistor configuration. A NPN transistor has electrons as majority charge carriers whereas the PNP transistor has holes as majority charge carrier. The mobility of electrons is better than mobility of holes. ... mobility of electrons is more than hole,so as a result npn transistor are faster than pnp that's why they are preferred.

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