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:
- Athe output signal leads the input signal by 90 degrees
- Bthe output signal lags the input signal by 90 degrees
- Cthe signals are in phase
- Dthe 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.
Practise this section
Advanced components and circuits is section A-002 of the Advanced exam: Advanced components and circuits: semiconductors, amplifier classes, oscillators, mixers, filters and digital logic.
Drill A-002 — free, no account