Electronics Device and Circuits - Transistor Biasing MCQs

In this section of Electronic Devices and Circuits.It contain Transistor Biasing MCQs (Multiple Choice Questions Answers).All the MCQs (Multiple Choice Question Answers) requires in depth reading of Electronic Devices and Circuits Subject as the hardness level of MCQs have been kept to advance level.These Sets of Questions are very helpful in Preparing for various Competitive Exams and University level Exams.

This Section covers below lists of topics :

Transistors Biasing MCQs.
Transistor Operating Point,Stabilization,stability factor MCQs.
Base Register Biasing, Feedback Register Biasing,Emitter Resister Biasing,Voltage Divider Biasing,Emitter Biasing MCQs.

Practice it now to sharpen your concept.

PRACTICE IT NOW TO SHARPEN YOUR CONCEPT AND KNOWLEDGE

1. For emitter bias, the voltage across the emitter resistor is the same as the voltage between the emitter and the

Base
Collector
Emitter
Ground

2. For emitter bias, the voltage at the emitter is 0.7 V less than the

Base voltage
Emitter voltage
Collector voltage
Ground voltage

3. With voltage-divider bias, the base voltage is

Less than the base supply voltage
Equal to the base supply voltage
Greater than the base supply voltage
Greater than the collector supply voltage

4. voltage-divider bias VDB is noted for its

Unstable collector voltage
Varying emitter current
Large base current
Stable Q point

5. With voltage-divider bias VDB, an increase in emitter resistance will

Decrease the emitter voltage
Decrease the collector voltage
Increase the emitter voltage
Decrease the emitter current

6. voltage-divider bias VDB has a stable Q point like

Base bias
Emitter bias
Collector-feedback bias
Emitter-feedback bias

7. voltage-divider bias VDB needs

Only three resistors
Only one supply
Precision resistors
More resistors to work better

8. voltage-divider bias VDB normally operates in the

Active region
Cutoff region
Saturation region
Breakdown region

9. The collector voltage of a VDB circuit is not sensitive to changes in the

Supply voltage
Emitter resistance
Current gain
Collector resistance

10. If the emitter resistance increases in a VDB circuit, the collector voltage

Decreases
Stays the same
Increases
Doubles

11. Base bias is associated with

Amplifiers
Switching circuits
Stable Q point
Fixed emitter current

12. If the emitter resistance doubles in a VDB circuit, the collector current will

Double
Drop in half
Remain the same
Increase

13. If the collector resistance increases in a VDB circuit, the collector voltage will

Decrease
Stay the same
Increase
Double

14. The Q point of a VDB circuit is

Hypersensitive to changes in current gain
Somewhat sensitive to changes in current gain
Almost totally insensitive to changes in current gain
Greatly affected by temperature changes

15. The base voltage of two supply emitter bias (TSEB) is

0.7 V
Very large
Near 0 V
1.3 V

16. If the emitter resistance doubles with TSEB, the collector current will

Drop in half
Stay the same
Double
Increase

17. If a splash of solder shorts the collector resistor of TSEB, the collector voltage will

Drop to zero
Equal the collector supply voltage
Stay the same
Double

18. If the emitter resistance increases with TSEB, the collector voltage will

Decrease
Stay the same
Increase
Equal the collector supply voltage

19. If the emitter resistor opens with TSEB, the collector voltage will

Decrease
Stay the same
Increase slightly
Equal the collector supply voltage

20. In TSEB, the base current must be very

Small
Large
Unstable
Stable

21. The Q point of TSEB does not depend on the

Emitter resistance
Collector resistance
Current gain
Emitter voltage

22. The majority carriers in the emitter of a PNP transistor are

Holes
Free electrons
Trivalent atoms
Pentavalent atoms

23. The current gain of a PNP transistor is

The negative of the NPN current gain
The collector current divided by the emitter current
Near zero
The ratio of collector current to base current

24. Which is the largest current in a PNP transistor?

Base current
Emitter current
Collector current
None of these

25. The currents of a PNP transistor are

Usually smaller than NPN currents
Opposite NPN currents
Usually larger than NPN currents
Negative

26. With PNP voltage-divider bias, you must use

Negative power supplies
Positive power supplies
Resistors
Grounds

27. For good stabilized biasing of the transistor of the CE amplifier . We should have: R_E/R_B >> h_rb

RE/RB << 1
RE/RB >> 1
R_E/R_B << h_rb
R_E/R_B >> h_rb

28. Current stability of a CC amplifier can be increased by

Reducing both emitter and base resistance
Increasing both emitter and base resistance
Reducing emitter resistance and increasing base resistance
Increasing emitter resistance and decreasing base resistance

29. Which of the following statements are correct for basic transistor amplifier configuration?

CB amplifier has low input impedance and a low current gain
CC amplifier has low output impedance and a low current gain
CE amplifier has very poor voltage gain but very high input impedance
The current gain of CB amplifier is higher than the current gain of CC amplifier

30. Which of the following configuration ifs normally used in cascading?

Common-emitter configuration
Common-base configuration
Common-collector configuration
None of the above

31. A transistor has h_fe = 27, then its h_fe will be:

–0.96
0.96
–27
–28

32. In the BJT amplifier, the transistor is biased in the forward active region putting a capacitor across R_E will:

Decrease the voltage gain and decrease the input impedance
Increase the voltage gain and decrease the input impedance
Decrease the voltage gain and increase the input impedance
Increase the voltage gain and increase the input impedance

33. In a common emitter BJT amplifier, the maximum usable supply voltage is limited by:

Avalanche breakdown of base–emitter junction
Collector–base breakdown voltage with emitter open (BVCBO)
Collector–emitter breakdown voltage with base open (BVCEO)
Zener breakdown voltage of the emitter -base junction

34. The transconductance g_m is defined as g_m = ∂i_o/∂V_BE its value in terms of h-parameters is:

h_ie/h_fe
h_fe/25
h_te/h_ie
None of the above

35. Introducing a resistor in the emitter of a common emitter amplifier stabilizes the dc operating point against variations in:

Only the temperature
Only the β of the transistor
Both temperature and β
None of the above

36. In a CE transistor amplifier, if collector–emitter voltage increases the instantaneous operating point:

Moves up the load line
Moves down the load line
Moves at right angle to the load line
Remains stationary

37. The h-parameter equivalent circuit of a junction transistor is valid for:

High frequency, large signal operation
High frequency, small signal operation
Low frequency, small signal operation
Low frequency, large signal operation

38. In a transistor h_fe = 50, h_ie = 830 ohms, h_oe = 10^–4 mho. When used as in the CB mode, then its output resistance will be:

2 m Ohms
500 K
2.5 M ohms
780 K

39. For obtaining hybrid parameters of a transistor:

Variable V_be and I_e are taken as independent variables
The two independent variables are the ones that are most easily measurable for a CE configuration
Variable i_b and v_ce ie are taken as dependent variables
Variable V_be and i_e are taken as dependent variables

40. The condition necessary to calculate h_oe of a transistor:

DC base current is to be zero
Base to emitter voltage is to be constant
Collector current is to be constant
Base current is to be constant

41. The approximate value of input impedance of a common emitter amplifier with emitter resistance R_e is given by:

h_ie + A₁R_e
h_ie + (1 + h_fe) R_e
h_ie
(1 + h_fe) R_e

42. To reverse bias the collector base Junction of silicon transistor, the minimum value of VCE required is

0.3 volt
0.5 world
1.0 volt
None of these

43. In the initial stage of transistor amplifier, the zero signal collector current IC is generally

0.5 mA
1.0 mA
1.5 mA

44. The Quiescent point Q in a voltage amplifier is selected in the middle of the active region because

It gives better stability
The circuit needs a small DC voltage
The biasing circuit that needs less number of resistors
It gives a distortion less output

45. The biasing circuit which gives best stability to the Q point is

Base register biasing
Feedback resistor biasing
Potential divider biasing
Emitter resistor biasing

46. The operating point of an NPN transistor amplifier should not be selected near the saturated region as it may

Cause output signal to be clipped in the positive half
Cause output signal to be clipped in a negative half
Require high DC supply
Drive the transistor to thermal Runaway

47. The biasing circuit has a stability factor of 40 . If due to temperature change, ICO changes by 1 microampere then IC will change by

20 microampere
40 microampere
80 microampere
None of these

48. Transistor operates in the active region when

Emitter and collector both junction forward biased
Emitter and collector both junction reverse biased
Emitter junction is forward biased and the collector junction is Reverse biased
Emitter junction is Reverse biased and the collector junction is forward biased

49. For faithful amplification with Germanium transistor, the base emitter junction voltage VBE should not fall below

0.3 volt
0.5 volt
0.7 volt
0.1 volt

50. The potential divider biasing is used in amplifiers to

Limit the input AC signal going to the base
Reduce DC base current
Reduce the cost of the circuit by limiting the number of resistors
Make the operating point almost independent of β

Electronics Device and Circuits – Transistor Biasing MCQs