Program : Undergraduate Level of Study: I st Level

Duration : 3 Hrs Time : 09:00 -12:00

Course Code: ECE 1311 Date October 21, 2000

Course Title: Electric CirCuits Section(s)

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JNSTRUCTION(S) TO CANDmA TE~'his is an OPEN-NOTES Examination. You may refer to manuscripts only.

RE"TfEWED BY--

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;.xamination Committee Member(s): I2LSJJfy

~2) The voltage signal shown below can be represented by v(t) = (6%)

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~3) A 16.Q. resistance and a 12 mH inductor are connected to a voltage source:\'s = 34 sin (1000 1) V. Draw the power triangle. (6%)

~4) For the circuit shown below, find the currents ;] and ;] when; is (a) 30 cas lOOOt A,(b) 30 cos.lOOOOtA. (10%)

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25cos (2000 t) V voltage source. The voltage across the inductor is required to havean amplitude of IOOV Oetennine the values of L and C, then find the cut-offfrequencies. .(10%)

5) For the circuit shown, the switch is at position 'a' for a long time before moving toposition 'b' at' = O. (a) What value ofC so that 9 mJ will be stored in the capacitor.(b) Select the value of'R' so that the circuit shall have a time-constant of Ims. (c)Detennine and sketch the voltage across the resistance for -I < t < 2 ms. (20%)

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7) In the circuit shown below; find the current ix and the power delivered to the 5 Qresistance. (20%)

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/:~\/'--- I2mF5 cos(125t) 0

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8) A three-phase, 900 V, 50 Hz source is supplying a balanced Y -connected load of(12+j18) .Q/Ph, connected in parallel with a A-connected load of (12-j18) .Q/ph. (a)Detennine the current delivered by the source. (b) Detennine the active and reactivepower-anatne]roadp~r-=~ctor=~eaChOf the two loads. (c) Draw the phasordiagram for all voltages and currents. "-1- -itIa'Lt (20%)

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