# The Transistor as an Amplifier MCQ’s

This set of Electronic Devices & Circuits Multiple Choice Questions & Answers (MCQs) focuses on “The Transistor as an Amplifier”.

1. The total emitter current (IE) is given by_________
a) IE = IpE * InE
b) IE = IpE – InE
c) IE = IpE / InE
d) IE = IpE + InE

2. A common base transistor amplifier has an input resistance of 20Ω and output resistance of 100kΩ. If a signal of 400mV is applied between emitter and base, find the voltage amplification. Assume αac to be one.
a) 20
b) 50
c) 30
d) 25

3. The emitter current consist of_________
a) electrons passing from collector to emitter
b) holes crossing from base to collector
c) electron current Ine constituted by electrons
d) immobile charge carriers

4. The amplification factor for a transistor is given by_________
a) A=αRL/re
b) A=αRLre
c) A=re/ αRL
d) A=RL/reα

5. The change in output voltage across the load resistor for a transistor during amplification is_________
a) RL *α*∆IE
b) RL *∆IE
c) RL *α2*∆IE
d) RL *α1/2*∆IE

6. A germanium transistor used as an amplifier has a collector cut off current ICBO=10µA at a temperature 27°C and β=50. What is the collector current when the base current is 0.25mA?
a) 10.76mA
b) 13.01mA
c) 15.67mA
d) 11.88Ma

7. Why is the silicon mostly chosen when compared to germanium?
a) low power consumption
b) high efficiency
c) greater working temperature
d) large ICBO

8. A transistor has an IC of 100mA and IB of 0.5mA. What is the value of αdc?
a) 0.565
b) 0.754
c) 1.24
d) 0.995

9. In a PNP germanium transistor, the cut in voltage is about_________
a) -0.1V
b) -0.01V
c) -0.05V
d) -0.07V

10. In a PNP transistor operating in active region, the main stream of current is_________
a) drift of holes
b) drift of electrons
c) diffusion of holes
d) diffusion of electrons