Transistor as an Amplifier

Q.

Which of the following is true?

1. Common base transistor is commonly used because current gain is maximum
2. Common emitter is commonly used because current gain is maximum
3. Common collector is commonly used because current gain is maximum
4. Common emitter is the least used transistor

Q. Current gain of a transistor in common base mode is 0.95. Its value in common emitter mode is

1. 1.5
2. 0.95
3. 19
4. (19)^–1

Q. Current gain in common base configuration is less than 1 because

1. I_e < I_b
2. I_b < I_e
3. I_c < I_e
4. I_e < I_c

Q.


For a common base configuration of \( P N P \) transistor \( \frac{l_{c}}{l_{z}}=0.98 \) then maximum current gain in common emitter configuration will be [CBSE PMT 2002]

Q. Current gain ${\beta }_{AC}$ in common emitter mode of transistor is

1. 
2. 
3. 
4. 

Q.

1. 
   

2. 
   

3. 
   

4. 
   

Q.

When NPN transistor is used as an amplifier :

1. Electrons move from base to collector

2. Holes move from emitter to base

3. Electrons move from collector to base

4. Holes move from base to emitter

Q. In a common emitter transistor amplifier $\beta$ = 60, $R_0$ = 5000 $\Omega$ and internal resistance of a transistor is 500$\Omega$. The voltage amplification of amplifier will be

1. 500
2. 460
3. 600
4. 560

Q.

In a common emitter transistor amplifier the audio signal voltage across the collector is 3V. The resistance of collector is $3k\Omega$. If current gain is 100 and the base resistance is $2k\Omega$, the voltage and power gain of the amplifier is

1. 15 and 200

2. 150 and 15000

3. 20 and 2000

4. 200 and 1000

Q.

For CE transistor amplifier, the audio signal voltage across the collector resistance of $2k\Omega$ is 4V. If the current amplification factor of the transistor is 100 and the base resistance is $1k\Omega$, then the input signal voltage is

1. 10 mV

2. 20 mV

3. 30 mV

4. 15 mV