PNP

The other kind of BJT is the PNP with the letters "P" and "N" standing for the majority charge carriers inside the dissimilar regions of the transistor.

Figure: The symbol of a PNP Bipolar Junction Transistor.

PNP transistors contain a layer of N-doped semiconductor among the two layers of P-doped material. A small current that is leaving the base in common-emitter mode is amplified in the collector output. In other words, a PNP transistor is "on" while its base is pulled low relative to the emitter.

The arrow (shown in figure) in the PNP transistor symbol is on the emitter leg and points in the direction of the conventional current flow while the device is in forward active mode.

One mnemonic device for making out the symbol for the PNP transistor is "pointing in proudly / 'pointing in - pah'."