A PNP transistor is a type of bipolar junction transistor (BJT) that consists of three layers of doped semiconductor materials. It has a collector, base, and emitter region, and is used to amplify or switch electronic signals.
A PNP transistor works by controlling the flow of current between the collector and emitter regions using the base region. When a small current is applied to the base, it allows a larger current to flow from the collector to the emitter, amplifying the signal.
The main difference between a PNP and NPN transistor is the direction of current flow. In a PNP transistor, current flows from the emitter to the collector, while in an NPN transistor, current flows from the collector to the emitter.
Voltage is used to control the flow of current in a PNP transistor. By applying a small voltage to the base, the transistor can amplify or switch larger currents between the collector and emitter.
The voltage in a PNP transistor circuit is typically measured using a voltmeter. The voltmeter is connected across the collector and emitter, or the base and emitter, to measure the voltage drop across those regions.