Use the same power and ground voltage levels that power the transistor circuit to switch the transistor on and off. Consider that if the PNP transistor is powered with a 5 Volt supply, it will require a 5 Volt signal to turn the PNP transistor off, and a 0 Volt (also known as a ground) signal to turn the PNP transistor on.
Determine which lead of the PNP transistor is the base lead, which is the collector lead and which is the emitter lead. Examine the transistor data sheet that the manufacturer provides to determine the identifying markings for the base, emitter and collector.
Understand that the base lead controls the switching action of the transistor. Realize that the voltage level applied to the PNP transistor's base will set the amount of electrical current that flows between the transistor's emitter and collector. Understand that if the voltage level on the base is low enough in relation to the voltage supply that powers the transistor, electrical current will flow between the emitter and the collector. Also realize that if the voltage level on the base is near the voltage supply level, no electrical current will flow between the emitter and collector,