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ECE602S - ELECTRICAL CIRCUIT AND ELECTRONIC - 2ND OPP - JANUARY 2025 |
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nAml BIA UnlVERSITY
OF SCIEnCE AnDTECHnOLOGY
Facultyof Health,Natural
ResourceasndApplied
Sciences
Schoolof Natural andApplied
Sciences
Department of Biology,
Chemistryand Physics
13Jackson Kaujeua Street
Private Bag 13388
Windhoek
NAMIBIA
T: +264 61207 2012
F: +264 61207 9012
E: dbcp@nust.na
W: www.nust.na
QUALIFICATION : BACHELOR OF SCIENCE
QUALIFICATION CODE: 07BOSC
COURSE:ELECTRICALCIRCUIT AND ELECTRONIC
DATE: JANUARY 2025
DURATION: 3 HOURS
LEVEL: 6
COURSECODE: ECE602S
SESSION: 1
MARKS: 100
SECOND OPPORTUNITY/SUPPLEMENTARY: EXAMINATION PAPER
EXAMINER:
MODERATOR:
INSTRUCTIONS
MR. MARKUS HITILA
DR. VAINO INDONGO
1. Answer all questions on the separate answer sheet.
2. Please write neatly and legibly.
3. Do not use the left side margin of the exam paper. This must be allowed for the
examir)er.
4. No books, notes and other additional aids are allowed.
5. Mark all answers clearly with their respective question numbers.
PERMISSIBLE MATERIALS:
l. Scientific Calculator
This paper consists of three pages including this front page
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Question 1
[15]
Describe an experiment to measure the open-circuit voltage of a cell. In your answer, explain
how Thevenin's theorem can be applied to simplify the circuit for this measurement and how
you can use the theorem to determine the internal characteristics of the cell
Question 2
[40]
Find v in the circuit of Fig. 1 by using
a) Nodal Analysis
(10)
b) Mesh Analysis
(10)
c) Superposition
(10)
d) Thevenin's and Norton's theorems
(10)
20.Q
9A
6A
20 n
+V
Figure 1: Circuit
20{2;
Question 3
[10]
Find the output voltage v0 and the output current i0 of the op-amp circuit shown
,.
0
Figure 2: Circuit
Question 4
[20]
The voltage and current were measured at the terminals of the device shown in the Figure.
The results are shown in the Table.
Electrical Circuits and Electronics (ECE602S)
2nd Opp/Supp Jan 2025 2
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a) Construct a circuit model for this device using an ideal current source and a resistor.
(10)
b) Use the model to predict the amount of power the device will deliver to a 200 resistor.
(10)
z,
--
-1I-
0
Device
(,
{
0
---
'Vt (V)
100
120
140
160
180
i, (A)
0
4
8
12
16
Figure 3: Experiment results and set up
Question 5
[15)
a) What is a transistor? Give two functions of a transistor
(2)
b) What are the charge carriers in P-type and N-type semiconductors
(2)
c) Describe the difference between P-type and N-type semiconductors materials (4)
d) For a CEtransistor amplifier, the audio signal voltage across the collector resistance of
2.0kW is 2.0V. suppose the current amplification factor of the transistor is 100, what
should be the value of R8 in series with V88 supply of 2.0V if the de base current must
be 10 times the signal current. Also calculate the de drop across the collector
resistance. Assume VEE= 0.6V
(7)
END OF QUESTION PAPER
Electrical Circuits and Electronics (ECE602S)
2nd Opp/SuppJan 2025
3