PNP Transistor Tutorial - The Bipolar PNP Transistor ConstructionVariantsExampleDesignOperationApplicationsPerformanceIntroductionFunctionBasically, in this type of transistor construction the two diodes are reversed with respect to the NPN type giving a Positive-Negative-Positive type of configuration, with the arrow which also defines the Emitter terminal this time pointing inwards in the transistor symbol. The construction of a PNP transistor consists of two P-type semiconductor materials either side of an N-type material as shown below.See more on electronics-tutorials How to Connect a PNP Transistor in a Circuit In a PNP transistor, with sufficient negative base current and sufficient positive voltage at the emitter, current will flow across from emitter to collector and power any device connected. The emitter is the source of current flow of a PNP transistor, meaning this is where the current flow is initiated. An Easy Way to Remember PNP and NPN Sensor Wiring Here’s a simple way remember how to wire up a 3-wire DC PNP or NPN sensor: PNP = Switched Positive. NPN = Switched Negative “Switched” refers to which side of the controlled load (relay, small indicator, PLC input) is being switched electrically. PNP Transistor Circuit Characteristics, Working, Applications PNP Transistor Working. The circuit connection of PNP transistor with supply voltages is given below. Here the base terminal has negative bias with respect to emitter and the emitter terminal has positive bias voltage with respect to both base and collector because of PNP transistor.