W1-2-60-1-6
JOMO KENYATTA UNIVERSITY
OF
AGRICULTURE AND TECHNOLOGY
University Examinations 2013/2014
STAGE III EXAMINATION FOR THE DIPLOMA IN INFORMATION TECHNOLOGY
DIT 0304 : ELECTRONICS CONSTRUCTION I
DATE: AUGUST 2013 TIME: 1½ HOURS
INSTRUCTIONS: ANSWER QUESTION ONE (COMPULSORY) AND
ANY OTHER TWO QUESTIONS.
QUESTION ONE (30 MARKS)
(a) Explain the following terms used in electrics:
(i) Capacitance. [2 marks]
(ii) Inductance. [2 marks]
(iii) Diode. [2 marks]
(b) A current of 6mA flows through a 30kΩ resistor. Calculate the potential difference developed across it. [2 marks]
(c) Explain two applications of capacitors in the field of electronics.
[4 marks]
(d) Explain the construction of the following fixed resistors:
(i) Wire would resistor. [2 marks]
(ii) Film resistor. [2 marks]
(iii) Carbon composition resistor. [2 marks]
(e) The bipolar junction transistors are mainly of two types. Explain them using diagrams. [2 marks]
QUESTION TWO (20 MARKS)
(a) (i) Explain the construction of a paper capacitor. [4 marks]
(ii) For the diagram shown below, calculate: [12 marks]
(I) The current drawn from the source.
(II) The Pd across each resistor.
(III) The current through each resistor.
(IV) The power dissipated by the 5Ω resistor.
(b) Explain any two transistor circuit configurations using appropriate diagram. [4 marks]
QUESTION THREE (20 MARKS)
(a) Discuss any four factors that determine the inductance of an inductor. [8 marks]
(b) A constant current of 2 micro amperes charges a capacitor for 40 seconds.
(i) How much charge is stored? [2 marks]
(ii) If voltage across capacitor is 50V calculate its capacitance.
[2 marks]
(c) (i) Describe four applications of PN-junction diodes.
[4 marks]
(iii) Using appropriate diagrams, explain the forward and reverse connections of a PN-junction diode. [4 marks]
QUESTION FOUR (20 MARKS)
(a) Using a full-wave bridge rectifier circuit, explain how full wave rectification is achieved. [8 marks]
(b) Explain any three factors that the capacitance of a capacitor depends on. [6 marks]
(c) For the circuit below, calculate: [6 marks]
(i) The voltage across C1.
(ii) The equivalent capacitance.
(iii) Charge stored in the circuit.
