Q1. If the common base current amplification factor α is 0.98, its common emitter current amplification factor β is

(a) 100
(b) 98
(c) 50
(d) 49

Q2. CE amplifier is used in intermediate stages in a multistage amplifier because

(a) its voltage gain is high
(b) its current gain is high
(c) its current gain as well as voltage gain in high
(d) its output impedance is very low

Q3. A transistor having α = 0.975 and reverse saturation current I∞  = 10 μA is operated in CE configuration. If the base current is 250 μА, then the collector current is

(a) 10.15 mA
(b) 9.75 mA
(c) 11.64 mA
(d) 8.56 mA

Q4. In a common emitter amplifier, the voltage gain depends mainly on

(a) hfe and hre
(b) hfe and hie
(c) hfe and hoe
(d) hre and hie

Q5. A multistage amplifier consists of three stages. The voltage gains of the stages are 30, 50 and 80 respectively. The overall voltage gain in dB will be

(a) 101.58
(b) 50.79
(c) 33.98
(d) 38.06

Q6. The hybrid parameter h21, in case of transistor is known as

(a) input impedance with output shorted
(b) output admittance with input open
(c) forward current gain with output shorted
(d) reverse voltage gain with input open

Q7. Indicate the false statement about the consequences of early effect in transistor

(a) α decreases with increasing |VCB|
(b) IB, decreases with increasing |VCB|
(C) IE increases with increasing |VCB|
(d) voltage breakdown may occur in transistor for large |VCB|

Q8. When operated in cut off and saturation, the transistor acts like a:

(a) a linear amplifier
(b) a switch
(c) a variable capacitor
(d) a variable resistor

Q9. Transistor is a:

(a) voltage controlled device
(b) current controlled device
(c) both voltage and current controlled device
(d) neither voltage nor current controlled device

Q10. When transistor is operating is active region, collector junction is :

(a) reversed biased for non transistor only
(b) reversed biased for pnp transistor only
(c) forward biased for both npn and pnp transistor
(d) reversed biased for both npn and pnp transistor

Q11. The transistor amplifier has highest input impedance in :

(a) CB configuration
(b) CE configuration
(c) CC configuration
(d) both in CC and CE configuration

Q12. Why does the collector current increases with increasing collector to base reverse bias voltage VEB for constant forward bias emitter base voltage VCB in common base configurations ?

(a) It is due to increase in effective base width
(b) It is due to decrease in concentration gradient of minority carriers in base region
(c) It is due to decrease in effective base width and increase in concentration gradient of minority carriers in base region
(d) It is due to increase in effective base width and decrease in concentration gradient of minority carriers in base region

Q13. For a given Ge transistor, the common base current gain is 0.98 and the reverse saturation current is 50 μA, then the collector current will be

(a) 2.45 mA
(b) 2.40 mA
(c) 2.50 mA
(d) 2.55 mA

Q14. Indicate the false statement about the common collector transistor amplifier

(a) Its input impedance is very high
(b) Its output impedance is very low
(c) Its voltage gain is slightly less than 1
(d) Its voltage gain is slightly more than 1

Q15. On increasing the value of bypass capacitor in RC coupled CE amplifier its

(a) voltage gain increases but lower cutoff frequency decreases
(b) voltage gain as well as lower cutoff frequency decreases
(c) voltage gain as well as lower cutoff frequency increases
(d) voltage gain decreases but lower cutoff frequency increases

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