For a constant collector-emitter voltage of 8 V, the collector current of a transistor reached to the value of 6 mA from 4 mA, whereas base current changed from $20 \mu \mathrm{~A}$ to $25 \mu \mathrm{~A}$ value. If transistor is in active state, small signal current gain (current amplification factor) will be:

JEE Main · 2022 · 27 Jul 2022 · Shift 2 · Semiconductors

For a constant collector-emitter voltage of 8 V, the collector current of a transistor reached to the value of 6 mA from 4 mA, whereas base current changed from

20 μ A

25 μ A

value. If transistor is in active state, small signal current gain (current amplification factor) will be:

(A)240
(B)400✓ Correct
(C)0.0025
(D)200

Answer: (B)

Solution

The small signal current gain (β) is defined as

β = \frac{Δ I _{C}}{Δ I _{B}}

. Given

Δ I_{C} = 6 - 4 = 2

mA and

Δ I_{B} = 25 - 20 = 5 μ

A. Therefore

β = \frac{2 \times 1 0 ^{- 3}}{5 \times 1 0 ^{- 6}} = \frac{2000}{5} = 400

JEE Main · 2022 · 27 Jul 2022 · Shift 2 · Single correct option

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JEE Main · 2022 · 27 Jul 2022 · Shift 2 · Semiconductors

Solution

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