# Electronic Devices and Circuits Questions and Answers – Analysis of Transistor Amplifier Circuit using h-parameters

This set of Electronic Devices and Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Analysis of Transistor Amplifier Circuit using h-parameters”.

1. What is the current gain of a transistor amplifier circuit if I1 = 10mA, I2 = 20mA, V1 = 25V, V2 = 15V?
a) -0.5
b) -2
c) 0.5
d) 2

Explanation: To calculate the current gain of a transistor amplifier circuit, we use the below formula. The current gain of a transistor amplifier is the ratio of output to input currents. Given the values of I1 = 10mA and I2 = 20mA.
Current gain = A = – I2 / I1 = 20 / 10 = 2.

2. How the current gain of a common emitter transistor amplifier expressed in terms of transistor hybrid parameters?
a) -hfe / (1 + ZL × hre)
b) hfe / (1 + ZL × hre)
c) -hfe / (1 + ZL × hoe)
d) hfe / (1 + ZL × hoe)

Explanation: The current gain of a transistor amplifier circuit is expressed as -I2 / I1. This can be expressed in terms of transistor hybrid parameters. The current gain of a common emitter transistor amplifier in terms of hybrid parameters is expressed as -hfe / (1 + ZL × hoe), where ZL is the load impedance.

3. How the current gain of a common base transistor amplifier expressed in terms of transistor hybrid parameters?
a) -hfb / (1 + ZL × hob)
b) hfb / (1 + ZL × hob)
c) -hfb / (1 + ZL × hrb)
d) hfb / (1 + ZL × hrb)

Explanation: The current gain of a transistor amplifier circuit is expressed as -I2 / I1. This can be expressed in terms of transistor hybrid parameters. The current gain of a common base transistor amplifier in terms of hybrid parameters is expressed as -hfb / (1 + ZL × hob), where ZL is the load impedance.

4. How the current gain of a common collector transistor amplifier expressed in terms of transistor hybrid parameters?
a) -hfc / (1 + ZL × hrc)
b) hfc / (1 + ZL × hrc)
c) -hfc / (1 + ZL × hoc)
d) hfc / (1 + ZL × hoc)

Explanation: The current gain of a transistor amplifier circuit is expressed as -I2 / I1. This can be expressed in terms of transistor hybrid parameters. The current gain of a common collector transistor amplifier in terms of hybrid parameters is expressed as -hfc / (1 + ZL × hoc), where ZL is the load impedance.

5. What is the input impedance of a transistor amplifier circuit if I1 = 10mA, I2 = 20mA, V1 = 25V, V2 = 15V?
a) 0.5kΩ
b) 2kΩ
c) 1.5kΩ
d) 2.5kΩ

Explanation: To calculate the input impedance of a transistor amplifier circuit, we use the below formula. The input impedance of a transistor amplifier is the ratio of input voltage to input current. Given the values of I1 = 10mA and V1 = 25V:
Input impedance = Zi = V1 / I1 = 25 / 10 = 2.5kΩ

6. How the input impedance of a common emitter transistor amplifier expressed in terms of transistor hybrid parameters?
a) hie – (hfe × hoe / YL + hre)
b) hie + (hfe × hoe / YL + hre)
c) hie – (hfe × hre / YL + hoe)
d) hie + (hfe × hre / YL + hoe)

Explanation: The input impedance of a transistor amplifier circuit is expressed as V1 / I1. This can be expressed in terms of transistor hybrid parameters. The input impedance of a common emitter transistor amplifier in terms of hybrid parameters is expressed as hie – (hfe × hre / YL + hoe), where YL is the load admittance.

7. How the input impedance of a common base transistor amplifier expressed in terms of transistor hybrid parameters?
a) -hib + (hfb × hib / YL + hob)
b) hib – (hfb × hib / YL + hob)
c) -hib + (hfb × hrb / YL + hob)
d) hib – (hfb × hrb / YL + hob)

Explanation: The input impedance of a transistor amplifier circuit is expressed as V1 / I1. This can be expressed in terms of transistor hybrid parameters. The input impedance of a common base transistor amplifier in terms of hybrid parameters is expressed as hib – (hfb × hrb / YL + hob), where YL is the load admittance.

8. How the input impedance of a common collector transistor amplifier expressed in terms of transistor hybrid parameters?
a) hic + (hfc × hrc / YL + hoc)
b) hic – (hfc × hrc / YL + hoc)
c) -hic + (hfc × hrc / YL + hoc)
d) -hic – (hfc × hrc / YL + hoc)

Explanation: The input impedance of a transistor amplifier circuit is expressed as V1 / I1. This can be expressed in terms of transistor hybrid parameters. The input impedance of a common collector transistor amplifier in terms of hybrid parameters is expressed as hic – (hfc × hrc / YL + hoc), where YL is the load admittance.

Sanfoundry Global Education & Learning Series – Electronic Devices and Circuits.