PNP Transistor (Bipolar)

Reverse the supply and current polarities of the NPN example to examine a complementary PNP device.

Circuit operation

I1 draws 20 µA from the base. The emitter connects to 5 V and RC returns the collector to ground. Both voltage probes use the emitter rail as their reference; the current arrows report positive branch-current magnitudes.

Expected behavior

$$|I_C|\approx\beta|I_B|=2\,\mathrm{mA}$$ $$V_{CE}=V_C-V_E\approx2-5=-3\,\mathrm V$$

The negative base-emitter and collector-emitter voltages distinguish this PNP bias from its complementary NPN case. This is forward-active operation, not saturation.

Reading the results

The first voltage probe is green and the second is red. Additional voltage traces use distinct colors. Current probes, when present, start with blue and then purple. The operating-point table opens with comfortable row spacing. Zoom to extents includes the complete schematic.

The operating-point table opens automatically with the steady-state voltages and currents.

Try a change

Set I1 DC current to 30 µA; collector current increases from about 2 mA to about 3 mA while the transistor remains forward-active. Restore the saved values after comparing the result.

Model limits

These are generic transistor models, not a specific manufactured part. The bipolar models use nominal forward current gain 100 with illustrative junction capacitances and transit times. Device mismatch, temperature drift, layout parasitics, breakdown and detailed noise are not represented. The schematic and component properties expose the values used.