AExE01 · Chapter 1Basic Electrical & Electronics🏛️ Past Licensure QuestionID: e8f8dfeb
In a Common-Emitter (C-E) amplifier, what is the phase relationship between the input signal and the output voltage?
In a Common-Emitter (C-E) amplifier, what is the phase relationship between the input signal and the output voltage?
Multiple Choice Options
- A
0 degrees
- B
90 degrees
- C
270 degrees
- D✓ Correct Option
180 degrees
Detailed Technical Solution & Explanation
In a Common-Emitter (C-E) transistor amplifier, an increase in base-emitter input voltage causes an increase in base and collector current, which increases the voltage drop across the collector resistor (), thereby pulling the collector-to-emitter output voltage () downwards. This produces an inherent 180° phase inversion between the input signal and the output voltage.
Option Analysis:
•
Option A (0 degrees): Incorrect. Common-Collector (emitter follower) and Common-Base have 0° phase shift.
•
Option B (90 degrees): Incorrect.
•
Option C (270 degrees): Incorrect.
•
Option D (180 degrees): Correct. The Common-Emitter configuration inherently produces 180° phase inversion.
Reference: Demo2 · Set 2NEC Licensure Syllabus