Advanced Qualification · A-002 Advanced components and circuits · A-002-007-006
In the common emitter amplifier, when the input and output signals are compared:
- A the output signal leads the input signal by 90 degrees
- B the output signal lags the input signal by 90 degrees
- C the signals are in phase
- D the signals are 180 degrees out of phase
Correct answer: D — the signals are 180 degrees out of phase. From the official ISED question bank, verified word for word.
Why
In a common emitter amplifier, when the input signal pushes the voltage up, the transistor conducts more current, which pulls the output voltage down, and vice versa. The full explanation — and one for every question — is in Pro.
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Advanced components and circuits: semiconductors, amplifier classes, oscillators, mixers, filters and digital logic.