BJT MCQ

1. Transistors were used in

1. First-generation computing devices
2. Second-generation computing devices
3. Third-generation computing devices
4. Fourth-generation computing devices

2. For normal operation of a transistor, the collector-base junction is

1. Always reverse biased
2. Always forward biased
3. Is grounded
4. Unbiased

3. Which of the statements given below is/are correct?

1. BJT is a current controlled device with high input impedance and high gain bandwidth
2. UJT is a positive resistance device and used as an oscillator
3. FET is a voltage-controlled device with high input impedance and low gain bandwidth.
4. BJT, FET, UJT can all be used for amplification

1. 1 and 2
2. 1 and 3
3. 2 and 4
4. only 3

4. If two identical transistors each having a current gain of 50 is connected in Darlington connection, the current gain of the connection will be

1. 625
2. 2250
3. 500
4. 2500

5. BJT has _________ input impedance and _________ output impedance.

1. Low, low
2. Low, high
3. High, low
4. High, high

6. Conventional flow of current in a P-N-P transistor is from

1. Emitter to base
2. Base to emitter
3. Base to collector
4. Emitter to collector

7. In a BJT, collector region width is maximum when it

1. collects the maximum number of charge carrier
2. reduces heat dissipation per unit area

Out of these

1. Only 1 is correct
2. Only 2 is correct
3. Both 1 and 2 are correct
4. Neither 1 nor 2 incorrect

8. In the active region of a transistor, collector-base junction is _________ biased.

1. Forward, forward
2. Reverse, reverse
3. Reverse, forward
4. Forward, reverse

9. The purpose of gold doping is for

1. Collector region of a BJT to used as a switch
2. Increasing collector current to use as a power amplifier
3. Reducing the lifetime of charge carriers
4. Collector region of a BJT to use as a switch and reducing the lifetime of charge carriers

10. In a BJT, when both junctions are forward biased then the operating mode is called

1. Reverse active mode
2. Forward active mode
3. Saturation mode
4. Cut-off mode

11. Following methods are used to increase the input resistance of a common emitter state (BJT). Arrange these methods in descending order of effectiveness.

1. Un-bypassing emitter resistance
2. Bootstrapping
3. Biasing it at low quiescent current
4. Using compounded BJTs

1. 2>4>1>3
2. 4>3>2>1
3. 2>4>3>1
4. 4>2>3>1

12. Base-bias is associated with

1. Amplifiers
2. Switching circuits
3. Stable Q-point
4. Fixed emitter current

13. If a transistor operates at the middle of the load line, a decrease in the current gain will move the Q-point

1. Down
2. Up
3. Nowhere
4. Off the load line

14. The current gain of a transistor is defined as the ratio of the collector current to the

1. Base current
2. Emitter current
3. Supply current
4. Collector current

15. A transistor is said to be in a quiescent stage when

1. Emitter junction bias is just equal to the collector
2. No current is flowing
3. No signal is applying to the input
4. It is biased

16. In transistor configuration producing highest output resistance is

1. CC
2. CB
3. CE
4. None of these

17. Transistor is a

1. Current control current device
2. Current control voltage device
3. Voltage control current device
4. Voltage control voltage device

18. The emitter region in N-P-N junction transistor is more heavily doped than the base region so that

1. The flow across the base region will be mainly due to electrons
2. The flow across the base region will be mainly due to holes
3. Base current will be high
4. There will be increase recombination in the base region

19. β of a transistor can exceed

1. 1
2. 0.1
3. 0.01
4. 0

20. The α of a transistor should be

1. 1
2. 0.99
3. 20
4. 0.01