electic assignment

7/29/2019 electic assignment

1/6

CONFIDENTIAL EE/OCT 2009/EEE231

UNIVERSITI TEKNOLOGI M ARAFINAL EXAMINATION

COURSECOURSE CODEEXAMINATIONTIME

ELECTRIC CIRCUIT 2EEE231OCTOBER 20093 HOURS

INSTRUCTIONS TO CANDIDATES1 . This question paper consists of five (5) questions.

Answer ALL questions in the Answer Boo klet. Start each answer on a new page..3.

4 .

Do not bring any material into the examination room unless permission is given by theinvigilator.Please check to make sure that this examination pack consists of:

i) the Question Paperii) an Answ er Booklet - provided by the Faculty

DO NOT TURN THIS PAGE UNTIL YOU ARE TOLD TO DO SOThis examination paper consists of 6 printed pag es

Hak Cipta Universiti Teknologi MARA CONFIDENTIAL


2/6

CONFIDENTIAL 2 EE/OCT 2009/EEE231

QUESTION 1a) For the circuit shown in Figure Q1a, find the expression for iL(t) and v0(f). The switch

was closed for a long time, at t = 0, the switch was open ed.4 Q t = 0

Figure Q1 a (10 m arks)b) For the circuit shown in Figure Q1b, the switch has been closed for a long time. At

t = 0, the sw itch is opened, then find vc(t) and calculate its value at t = 8 s and t = 10 s.

Figure Q1b (10 m arks)



3/6


QUESTION 2a) The circuit shown in Figure Q2a is operating in the sinusoidal steady state with the

voltage source, vs (t ) = 200 cos (lOOOt + 40 )V.i) Construct the phasor domain equivalent circuit.ii) Calculate the phasor voltage V2.iii) Calculate the current is(t) and ia(t) in the circuit.

's(t). 25 Q

v.(t)

15QAAA^50|aF

25 mH_fYYY\_

ia(t)1 0 Q

AA/V 2 0 mH20 Q.

FigureQ2a

V,

(10 marks)b) Determine the mesh currents of la, lb, and lcin the circuit shown in Figure Q2b by usingmesh analysis. Then, find V0.

Q ) l 2 Z 9 0 V

Figure Q2b (10 marks)

HakCipta Universiti Teknologi MARA CONFIDENTIAL


4/6


QUESTION 3a) Using nodal analysis, find V0 and l0 in the circuit of Figure Q3a.

Figure Q3a (10 m arks)b) Find the Norton equivalent circuit with respect to the terminals a, b for the circuit shown

in Figure Q 3b. Given Vs = 5Z0 V,

200 Q, -J50Q a

Figure Q3b (10 marks)



5/6


QUESTION 4a) For the circuit shown in Figure Q4a;

Load 1 absorbs 50 kW and 40 kVAR laggingLoad 2 absorbs 40 kW at a 0.8 pf laggingLoad 3 has 10 kW and 12 kVAR (capacitive)i)

ii)

State the complex power for each load. (4 marks)Calculate overall complex power and power factor. The value of the capacitanceconnected in parallel that will raise the power factor to 0.95 lagging.

230 Vrms50 HzL1

L2

L3Figure Q4a (6 marks)

b) For the circuit shown in Figure Q4b, calculate the Mutual Inductance M^ M 2 and M3(in Henry) and hence determine the current l x .

6 Q-A/vV

5 m H

6cos(100 t+90)A

AA/V8 Q p m r ^60 mHFigure Q4b

2 Q-A/VV

M 3^ 3 0 m H k3 = 0 .9 ] ? 4 Q

1 0 c o s ( 1 0 0 t ) A(10 marks)

Hak Cipta Universiti Teknologi MA RA CONFIDENTIAL


6/6


QUESTION 5a) Figure Q5a shows a connection of a two-port network system. Using the parameters

given, solve the followings:Y 0.25 0.50.15 0.35

i) Current gain, A|.ii) Voltage gain, Av.iii) Hence, determine the overall voltage gain, AVT-

RS=20Q _J iA/WRL=80Q

Figure Q5a (10 marks)b) A series R-L-C circuit with 40 W and 20 V source is designed to resonant atcor =1000 rad/s and bandwidth of 0.15fr.

) Determine the value of R .i) Find the bandwidth in hertz .ii) Determine the quality factor at resonant.v) Find the value of L and C. (10 marks)

END OF QUESTION PAPER


electic assignment

Documents