TUTORIAL_2A_Q-BENT1123 Electrical Circuit Analysis
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BENT 1123_Sem1_1011 – TUTORIAL 2 ____________________________________________________________________________________________________________ ___________________________________________________________________ 1 UNIVERSITI TEKNIKAL MALAYSIA MELAKA FACULTY OF ELECTRONIC ENGINEERING AND COMPUTER ENGINEERING BENT 1123 ELECTRICAL CIRCUIT ANALYSIS TUTORIAL 2 (AC ANALYSIS & POWER ANALYSIS) Average Power 1. Given the circuit in Fig. 1, find the average power supplied or absorbed by each element. Figure 1 Answer: Pc = PL = 0 W, PR = 47.65 W 2. A load consists of a 60-Ω resistor in parallel with a 90-µF capacitor. If the load is connected to a voltage source v s (t) = 40cos 2000t, find the average power delivered to the load. Answer: P R = 13.333 W . Maximum Average Power Transfer 3. Find the value of Z L in the circuit of Fig. 3 for maximum power transfer. Figure 3. Answer: = L Z Ω − 15 . 10 j 23 . 21
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UTeMBENT1123 electrical circuit analysis
Transcript of TUTORIAL_2A_Q-BENT1123 Electrical Circuit Analysis
BENT 1123_Sem1_1011 – TUTORIAL 2 ____________________________________________________________________________________________________________
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UNIVERSITI TEKNIKAL MALAYSIA MELAKA FACULTY OF ELECTRONIC ENGINEERING AND COMPUTER ENGINEERING
BENT 1123 ELECTRICAL CIRCUIT ANALYSIS TUTORIAL 2 (AC ANALYSIS & POWER ANALYSIS)
Average Power 1. Given the circuit in Fig. 1, find the average power supplied or absorbed by each element.
Figure 1
Answer: Pc = PL = 0 W, PR = 47.65 W 2. A load consists of a 60-Ω resistor in parallel with a 90-µF capacitor. If the load is connected to a voltage source vs(t) = 40cos 2000t, find the average power delivered to the load. Answer: PR = 13.333 W. Maximum Average Power Transfer 3. Find the value of ZL in the circuit of Fig. 3 for maximum power transfer.
Figure 3. Answer: =LZ ΩΩΩΩ−−−− 15.10j23.21
BENT 1123_Sem1_1011 – TUTORIAL 2 ____________________________________________________________________________________________________________
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4. The variable resistor R in the circuit of Fig. 4 is adjusted until it absorbs the maximum average power. Find R and the maximum average power absorbed
Figure 4
Answer: =LR 2.576Ω, Pmax = 3.798 W Apparent Power and Power Factor 5. An ac motor with impedance ZL = 4.2 + j3.6 Ω is supplied by a 220-V, 60-Hz source. (a) Find pf, P, and Q. (b) Determine the capacitor required to be connected in parallel with the motor so that the power factor is corrected to unity. Answer: a) P = 6.643 kW, Q = 5.695 kVAR b) C = 312 uF 6. Obtain the power factor for each of the circuits in Fig. 6. Specify each power factor as leading or lagging
Figure 6
Answer: a) =pf (leading)5547.0 b) =pf (lagging)9304.0
BENT 1123_Sem1_1011 – TUTORIAL 2 ____________________________________________________________________________________________________________
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Complex Power 7. Determine the complex power for the following cases:
(a) P = 269 W, Q= 150 VAR (capacitive) (b) Q = 2000 VAR, pf = 0.9 (leading) (c) S = 600 VA, Q = 450 VAR (inductive) (d) Vrms = 220 V, P = 1 kW, |Z| = 40 Ω (inductive)
Answer: a) =S VA150j269 −−−− b) =S VA2000j4129 −−−− c) =S VA450j9.396 ++++
c) =S VA2.681j1000 ++++
8. For the entire circuit in Fig. 8, calculate:
(a) the power factor (b) the average power delivered by the source (c) the reactive power (d) the apparent power (e) the complex power
Figure 8 Answer: (lagging)9956.0 , 1.751 kW, 164.9 VAR, 1.7587 kVA , (1,751 + j164.9) VA
120∠∠∠∠45ºV
