Family Name Other Names Global ID Date
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Diplomas
Electrical and Telecommunications Engineering
EE1111
Question
Possible Marks
Actual Marks
1
30
2
30
3
30
4
10
Total
100
Type of Assessment Reading time: 10 minutes Working time: 105 minutes Intake/Year: DipC / 2018
UNSW Diplomas
UNSW Global Pty Limited
UNSW Sydney NSW 2052 Australia
Copyright 2018
All rights reserved. Except under the conditions described in the Copyright Act 1968 of Australia and subsequent amendments, this publication may not be reproduced, in part or whole, without the permission of the copyright owner.
Directions to Candidates
This paper contains 8 pages.
Candidates must ATTEMPT ALL questions.
Answer each question in a separate answer booklet.
Marks for each question are indicated beside the question.
This paper MAY NOT be retained by the candidate.
Print the question number on the front page of each answer book. Authorised examination materials:
Candidates should use their own UNSW-approved electronic calculators.
This is a closed book examination.
Assumptions made in answering the questions should be stated explicitly.
All answers must be written in ink. Except where they are expressly required, pencils may only be used for drawing, sketching or graphical work.
For the numerical solutions, you can use either fraction form or floating-point form (maximum 2 digits after decimal point is enough)
QUESTION 1 [30 marks]
(i) [15 marks] Calculate the equivalent resistance for the circuit shown in Figure 1.
Figure 1
(ii) [15 marks] Calculate 𝐶𝐶𝑒𝑒𝑒𝑒 for the circuit shown in figure 2.
2F
Ceq
3F
1F1F3F2F
2F
Figure 2
QUESTION 2 [30 marks]
(i) [10 marks] Apply nodal analysis to find 𝑉𝑉0 in the circuit of Figure 3.
V1
V2
Figure 3 (ii) [20 marks] For the circuit shown in Figure 4,
a. (5marks)Applymeshanalysisandshowthatmeshequationsaregivenas
below:
10𝑖𝑖2 − 20𝑖𝑖1 = −400 � −10𝑖𝑖1 + 20𝑖𝑖2 = 0
𝑖𝑖3 = −10 𝐴𝐴
b. (5marks)Giventhevaluesofmeshcurrentsasi1 =80 A,i2 =40 Aandi3 =-10
A, calculate the power supplied by each source.
33
c. (10marks)Giventhevaluesofmeshcurrentsasi1 =80 A,i2 =40 Aandi3 =-10
A, find 𝑉𝑉0.
33
i1
i2
i3
Figure 4
QUESTION 3 [30 marks]
(i)
[20 marks] For the circuit shown in Figure 5, find the current 𝑖𝑖 in the 4-Ω resistor using,
a. (10marks)Thesuperpositionprinciple.
b. (10marks)TheTheveninequivalentofthecircuittotheleftofterminalpaira-b.
20 V 2Ω
a
i
b
1Ω 2A
4Ω
3Ω
Figure 5
(ii)
[10 marks] Find the Norton equivalent of the circuit given in Figure 6.
Figure 6
QUESTION 4 [10 marks]
In the circuit of Figure 7, the switch has been in the open position for a long time before closing at time 𝑡𝑡 = 0.
a. (4marks)Giveanexpressionforthecapacitorvoltage𝑣𝑣𝑐𝑐(𝑡𝑡)(i.e.,asafunction of time) for 𝑡𝑡 > 0.
b. (3 marks) Give an expression for the capacitor current 𝑖𝑖𝑐𝑐(𝑡𝑡) for 𝑡𝑡 > 0.
c. (3 marks) Give an expression for the current of the 40-Ω resistor 𝑖𝑖𝑅𝑅40(𝑡𝑡) for 𝑡𝑡 > 0.
10 V
10 Ω
+ Vc –
40 Ω 1mF
Figure 7
50 Ω
t=0
35 V
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