A transistor is used in common-emitter mode in an amplifier circuit. When a signal of 10 mV is added to the base-emitter voltage, the base current changes by $10 \mu \mathrm{~A}$ and the collector current changes by 1.5 mA. The load resistance is $5 \mathrm{k} \Omega$. The voltage gain of the transistor will be ______.

JEE Main · 2022 · 24 Jun 2022 · Shift 1 · Semiconductors

A transistor is used in common-emitter mode in an amplifier circuit. When a signal of 10 mV is added to the base-emitter voltage, the base current changes by

10 μ A

and the collector current changes by 1.5 mA. The load resistance is

5 k Ω

. The voltage gain of the transistor will be ______.

Answer: 750

Solution

Input resistance:

r_{i} = \frac{Δ V _{B E}}{Δ I _{B}} = \frac{10 mV}{10 μ A} = 1000 Ω

Current gain:

β = \frac{Δ I _{C}}{Δ I _{B}} = \frac{1.5 mA}{10 μ A} = 150

Voltage gain in CE mode:

A_{V} = β \times \frac{R _{0}}{r _{i}} = 150 \times \frac{5000}{1000} = 150 \times 5 = 750

The answer is 750.

JEE Main · 2022 · 24 Jun 2022 · Shift 1 · Integer answer

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JEE Main · 2022 · 24 Jun 2022 · Shift 1 · Semiconductors

Solution

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