The base of a transistor is lightly doped because it carries the electrons from the emitter and passed them to the collector region. There should be less recombination in the base region.
2. Who is larger in size?
A. Base
B. Collector
C. Emitter
D. P-N Junction
Answer: A
The collector is larger in size because it receives the electrons from the base region. If it is not bigger in the sizer there will be crowding of electrons which causes high power dissipation.
3. Calculate the collector current using the data: IE=14 mA, IB=7 mA.
A. 7 mA
B. 8 mA
C. 9 mA
D. 10 mA
Answer: A
The collector current in the transistor is
IE – IB=14-7=7 mA.
The KCL equation IE=IB+Ic is always in every configuration of the transistor.
4. Calculate the current gain using the data: Ic=25 mA, IB=10 mA.
A. 3.5
B. 2.5
C. 1.4
D. 7.8
Answer: B
The current gain is represented as β in electronic circuits. The current gain is the ratio of the collector current and base current.
β=Ic÷IB=25÷10=2.5.
5. Calculate the value of ∝ using the data: Ic=18 mA, IE=17 mA.
A. 1.05
B. 1.47
C. 1.89
D. 2.55
Answer: A
The value ∝ is Ic÷IE.
The current gain is the ratio of the collector current and base current.
∝=Ic÷IE=18÷17=1.05.
6. In a transistor, Ic=47 mA and IE=53 mA. The value of β is __________
A. 8.48
B. 7.83
C. 9.26
D. 3.15
Answer: B
The value of β is Ic÷IB.
The value of IB=IE-Ic=53-47=6 mA. The value of β is
Ic÷IB=47÷6=7.83.
7. Choose the correct relationship between β and ∝.
A. β=∝/(1-∝)
B. β=1/(1+∝)
C. β=1/(1-∝)
D. β=1/(∝)
Answer: A
The relationship between β and ∝ is β=∝/(1-∝).
The current gain is the ratio of the collector current and base current. The value of β is Ic÷IB.
8. A Transistor is a current operated device.
A. True
B. False
Answer: A
A transistor is a current-operated device. The value of the collector current is α times of the emitter current. It is a current controlled device.
9. Calculate the value of β for α=.8.
A. 2
B. 8
C. 3
D. 4
Answer: D
The relationship between β and ∝ is
β=∝/(1-∝)=.8÷.2=4.
The current gain is the ratio of the collector current and base current. The value of β is Ic÷IB.
10. Which one of the following is correct?
A. IE=IB+Ic
B. IE=IB-Ic
C. IE=Ic
D. IE=IB
Answer: A
The KCL equation that holds correct is IE=IB+Ic. At any point emitter current is the sum of the base current and collector current.
