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Difficulty: Very hardTransistors

For a silicon PNP bipolar junction transistor to operate correctly in the active region as a linear amplifier, the DC biasing circuit must ensure that the collector terminal is maintained at a higher positive voltage relative to the emitter terminal.

Answer: Answer

Answer

False
The statement is false because in a PNP transistor, the emitter must be at a higher positive potential than the collector to ensure current flows correctly (from emitter to collector) and the junctions are properly biased for the active region.

Step-by-Step Solution

1
Identify the specific transistor type and its intended operating state.
The device is a PNP bipolar junction transistor operating in the active region (as a linear amplifier).
Different transistor types (NPN vs. PNP) require completely opposite voltage polarities for the same operating state.
2
Recall the structural composition of a PNP transistor.
A PNP transistor consists of a P-type emitter, an N-type base, and a P-type collector.
Understanding the semiconductor materials (P or N) dictates how junctions must be biased.
3
Determine the required junction biasing for the active region.
For any BJT to act as a linear amplifier (active region), its emitter-base junction must be forward-biased, and its collector-base junction must be reverse-biased.
This specific biasing arrangement allows a small base current to control a larger collector current without entering saturation or cutoff.
4
Apply the biasing rules to the PNP terminal voltages.
To forward-bias the P-N emitter-base junction, the P-type emitter must be more positive than the N-type base. To reverse-bias the P-N collector-base junction, the P-type collector must be more negative than the N-type base.
Forward biasing requires connecting positive potential to P-type material; reverse biasing requires connecting negative potential to P-type material.
5
Evaluate the statement based on the deduced voltage potentials.
The emitter is the most positive terminal in a properly biased PNP amplifier circuit. Therefore, the collector is at a lower voltage relative to the emitter, making the original statement false.
The statement claims the collector is at a higher positive voltage, which incorrectly describes an NPN transistor's biasing.

Key Concept

Transistor Biasing and Polarity Configuration
Estimated Time:1m 30s
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Topics

Transistors

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