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Ele 101: Semiconductor Electronics Question Paper

Ele 101: Semiconductor Electronics

Course:Diploma In Computer Science

Institution: The Presbyterian University Of East Africa question papers

Exam Year:2016

COURSE CODE : ELE 101

COURSE TITLE : SEMICONDUCTOR ELECTRONICS

STUDENTS: 5

SECTION A

Question One

Using a diagram, distinguish between majority and minority carriers in a semiconductor. (8 Marks)
Compare the merits and demerits of semiconductor diodes and vacuum diodes.
(6 Marks)

Differentiate between FET and BJT transistors. (4 Marks)
Explain the formation of a potential barrier in a p-n junction and show the polarity of the Barrier potential. (6 Marks)
Explain physically how a p-n junction functions as a rectifier. (6 Marks)
SECTION B

Question Two

Explain how a Zener diode can be used as voltage regulator. (6 Marks)
Can an ordinary diode be used as a zener diode? Justify your answer. (4 Marks)
Explain the consequences for the BJT if a large amount of power is dissipated and describe a technique that may be used to minimize the effect. (5 Marks)
Question Three

Give one example where an unregulated power supply may be acceptable and one example where a regulated power supply is required. (6 Marks)
Discuss the similarities and differences between JFET and MOSFET with regard to their construction and applications. (7 Marks)
In relation to power supply units, explain the meaning of the terms percentage load regulation and percentage line regulation. (6 Marks)
Question Four

Write out the equation for Ohms law showing the relationship between voltage, current and resistance in an electrical circuit. (3 Marks)
Given a resistance of 220 connected to an e.m.f. of 10 V Calculate the expected current flow through the resistor. (4 Marks)
Explain the likely consequences of increasing the value of the resistor to 270.
(4 Marks)
The resistor is replaced by one with a value of 22. Calculate the new value of current flow and the required power rating for the resistor. (4 Marks)
Question Five

Explain the principle of operation of LED and mention the materials used for it.
(7 Marks)
What is electron emission and mention different types of electron emissions.
(5 Marks)
Explain what the term de-rating means and describe how it may be used in order to improve the long-term reliability of an electronic component. (3 Marks)

Ele 101: Semiconductor Electronics Question Paper

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