A transistor is used as an amplifier because a small change in the base current produces
- A. no change in the collector current
- B. a much larger change in the collector current
- C. a smaller change in the collector current
- D. a change only in the emitter voltage
Explanation
The current gain of a common emitter transistor is typically between 50 and 300, so a weak input signal at the base controls a much larger collector current and the extra energy comes from the power supply. The transistor does not create energy; it controls the flow of it. Used in saturation and cut off instead, the same device acts as a switch.