A small current flowing from the base allows a much greater current to flow from the emitter to the collector. PNP transistors are commonly operated with the collector at ground and the emitter connected to a positive voltage through an electric load. PNP transistors consist of a layer of N-doped semiconductor between two layers of P-doped material. Few transistors used today are PNP, since the NPN type gives better performance in most circumstances. The other type of BJT is the PNP with the letters 'P' and 'N' referring to the majority charge carriers inside the different regions of the transistor.

The arrow in the NPN transistor symbol is on the emitter leg and points in the direction of the conventional current flow when the device is in forward active mode.ДЄ convenient mnemonic device for identifying the symbol for the NPN transistor is 'not pointing in'. A small current entering the base in common-emitter mode is amplified in the collector output. NPN transistors consist of a layer of P-doped semiconductor (the 'base') between two N-doped layers. Most bipolar transistors used today are NPN, because electron mobility is higher than hole mobility in semiconductors, allowing greater currents and faster operation. NPN is one of the two types of bipolar transistors, in which the letters 'N' and 'P' refer to the majority charge carriers inside the different regions of the transistor. Bipolar transistors are so named because their operation involves both electrons and holes.ДЄlthough a small part of the transistor current is due to the flow of majority carriers, most of the transistor current is due to the flow of minority carriers and so BJTs are classified as 'minority-carrier' devices. It is a three-terminal device constructed of doped semiconductor material and may be used in amplifying or switching applications.

enjoy your stay, I hope this site is useful to you.ДЄ bipolar junction transistor (BJT) is a type of transistor. Welcome! this site is all about electronic devices and their corresponding electrical symbol. Electronic Symbols: NPN & PNP Transistors

Pnp transistor symbol