Part 2: PNP Transistors
transistor is formed by sandwiching a
layer of N-type semiconductor between two layers of P-type semiconductor.
PNP Transistor Diagram
A PNP Transistor
operates in much the same fashion as an NPN transistor, but because
the layers are reversed, the voltage relationships must also be
reversed. Thus, both the base and collector terminals must be negative
in relation to the emitter for the device to be turned on.
PNP Transistor On
PNP Transistor Symbol
junction in both PNP and NPN transistors must be forward-biased
to turn the transistor on - that is, the voltage on the P layer
must be at least 0.7 volts higher than the voltage on the N layer.