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Bipolar Junction Transistor NAT Level -1

10 Questions MCQ Test Solid State Physics, Devices & Electronics | Bipolar Junction Transistor NAT Level -1

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Attempt Bipolar Junction Transistor NAT Level -1 | 10 questions in 30 minutes | Mock test for IIT JAM preparation | Free important questions MCQ to study Solid State Physics, Devices & Electronics for IIT JAM Exam | Download free PDF with solutions

*Answer can only contain numeric values

QUESTION: 1

For a transistor circuit, V_CE when V_in = 0V (in volts).

Solution:

When V_in = 0V, the transistor is in cut-off (acts like an open switch) and V_CE =V_{CC =}10V.
The correct answer is: 10

*Answer can only contain numeric values

QUESTION: 2

For a BJT, the current amplification factor ∝ = 0.9 . This transistor is connected in common emitter configurations. When the base current changes by 0.4 mA, the change in collector current will be (in mA).

Solution:

The correct answer is: 3.6

*Answer can only contain numeric values

QUESTION: 3

A power amplifier gives 150 W output of or an input of 1.5W. The gain in dB is :

Solution:

= 40 dB
The correct answer is: 40

*Answer can only contain numeric values

QUESTION: 4

What is the current gain for a common-base configuration where I_E = 4.2 mA and I_C = 4.0 mA?

Solution:

Ie = 4.2ma (Given)

Ic = 4.0ma (Given)

The question follows the common base configuration in the circuit configuration of a bipolar transistor, where the emitter is the input electrode, collector is the output electrode and the base is reference electrode for both input and the output.

Thus,

Current gain = Ic / Ie =I(out)/I(in)

where, IC=Output Current and IE = Input Current

= 4 / 4.2

= 0.95

Therefore, the current gain for a common-base configuration is 0.95

*Answer can only contain numeric values

QUESTION: 5

Figure shows a common emitter amplifier with β = 100. What is the maximum peak to peak input signal (in mV) for which distortion free output may be obtained Assume V_BE = 0 r_E= 20 Ω

Solution:

But for maximum peak to peak input signal

The correct answer is: 80

*Answer can only contain numeric values

QUESTION: 6

In the following circuit, Tr₁ and Tr₂ are identical transistors having V_BE = 0.7V. The current passing through the transistor Tr₂ is (in mA).

Solution:

Applying KVL,
5=100x1 + 0.7

The correct answer is: 43

*Answer can only contain numeric values

QUESTION: 7

If the transistor amplifier has a gain of 20dB, then the ratio of output to input power is :

Solution:

The ratio of output to input power is known as power amplification.

The logarithm of the power amplification is represented in bel.

he correct answer is: 100

*Answer can only contain numeric values

QUESTION: 8

A common emitter amplifier has voltage gain of 50, an input impedance of 1000Ω and an output impedance of 200Ω. The power gain of the amplifier will be (in dB).

Solution:

Power gain = Voltage gain x current gain

The correct answer is: 250

*Answer can only contain numeric values

QUESTION: 9

The input signal given to a common emitter amplifier having a voltage gain of 20 is V_in = 20 cos (5t + 20°). The corresponding output signal has an amplitude equal to ?

Solution:

The correct answer is: 400

*Answer can only contain numeric values

QUESTION: 10

The feedback ratio of an amplifier, which an amplification of a negative feedback, changes the voltage gain the voltage gain from - 250 to - 100 is (give magnitude only).

Solution:

The correct answer is: 0.006