In a PNP transistor, the device turns on when the base is relative to the emitter:

In a PNP transistor, the device turns on when the base is relative to the emitter:

• A. Positive with respect to the emitter
• B. Equal to the emitter
• C. More positive than the emitter
• D. Negative with respect to the emitter

Answer: (D)

In a PNP transistor, turning on requires forward bias of the base–emitter junction. For a PNP device, that happens when the base sits at a lower potential than the emitter by about 0.6–0.7 V (silicon). So the base must be negative with respect to the emitter. When VB is lower than VE by this amount, holes flow from the emitter into the base, enabling current to flow from emitter to collector and the transistor conducts. If the base were equal to or more positive than the emitter, the base–emitter junction wouldn’t be forward biased, and the transistor stays off.

In a PNP transistor, turning on requires forward bias of the base–emitter junction. For a PNP device, that happens when the base sits at a lower potential than the emitter by about 0.6–0.7 V (silicon). So the base must be negative with respect to the emitter. When VB is lower than VE by this amount, holes flow from the emitter into the base, enabling current to flow from emitter to collector and the transistor conducts. If the base were equal to or more positive than the emitter, the base–emitter junction wouldn’t be forward biased, and the transistor stays off.