Consider an n-p-n transistor amplifier in common emitter configuration. The current gain of the transistor is 100. If the collector current changes by 1 mA, what will be the change in emitter current?

Question

Consider an n-p-n transistor amplifier in common emitter configuration. The current gain of the transistor is 100. If the collector current changes by 1 mA, what will be the change in emitter current? (A) 1.1 mA (B) 1.01 mA (C) 0.01 mA (D) 10 mA

Tardigrade Admin · Accepted Answer

Current gain is defined as ratio of collector current to base current.
Current gain

= \frac{change in collector current}{change in base current}

β = \frac{Δ i _{C}}{Δ i _{B}}

Also

i_{E} = i_{B} + i_{C}

\Rightarrow Δ i_{E} = Δ i_{B} + Δ i_{C}

β = \frac{Δ i _{C}}{Δ i _{E} - Δ i _{C}}

Given,

β = 100, Δ i_{C} = 1 m A

∴ 100 = \frac{1}{Δ i _{E} - 1}

Δ i_{E} - 1 = \frac{1}{100} = 0.01

Δ i_{E} = 1 + 0.01 = 1.01 m A .

In common-emitter amplifier, the output voltage signal is

18 0^{\circ}

out of phase with the input voltage signal.

Q. Consider an n−p−n transistor amplifier in common emitter configuration. The current gain of the transistor is 100. If the collector current changes by 1mA, what will be the change in emitter current?

1.1 mA

1.01 mA

0.01 mA

10 mA

Q. Consider an $n - p - n$ transistor amplifier in common emitter configuration. The current gain of the transistor is $100$ . If the collector current changes by $1 m A$ , what will be the change in emitter current?