Principles of Electrical Eng

Re q 3  2 A 2  1  12  6  10  + V - a b 6  4 V 3 A 2  2  I 1 V3 4  Vref = 0 - + 3 V V1 ELEC-275/4 Midterm Exam March 3, 2013. CONCODIA UNIVERSITY Department of Electrical & Computer Engineering ELEC-275/4: Winter 2013 Midterm Exam Date: March 3, 2013. Time: 75 Minutes. Dr. S. K. Das Answer all the questions. _________________________________________________________

ELEC_275_Midterm_Winter_2013.docx-Re q 3  2 A

Elec 275 – Principles of Electrical Engineering (Final) Fall 2012 1. Fig.1 shows an ac circuit. The various component values are given by: v s (t) = 100 sin [(100π) t], R 1 = 500 ohms, R 2 = 100 ohms, L = 1.014 H , C = 10 µF. Fig.1. (a) Draw the circuit in phasor form, showing all the values of the components. (b) Write the two mesh equations. ( Only the meshes shown shall be considered). (c) Calculate the values of I 1 and I 2 . (d) Present a time domain equation for the voltage across the inductor with the polarity indicated in the figure. (8 marks) 2. For the network shown in Fig.2, (a) Obtain the expression of the input impedance Z ab in terms of R 1 , R 2 , C 1 , C 2 and the operating frequency ω, (b) Determine the frequency ω o at which Z ab is purely resistive. (c) At this frequency ω o , obtain the value of Z ab = R ab + j0. The various component values are given by: R 1 = 1k ohms, R 2 = 1 k ohms, C 1 = 10 - 3 F, and L 2 = 1 mH. (ω = 0 and ω = ∞ should not be considered.) Fig.2. (9 marks) 2 of 6/- Elec 275 – Principles of Electrical Engineering (Final) Fall 2012 3. Fig.3 shows an electrical network given in the time-domain. (a) Write the nodal equations using I s1 , I s2 , V s , R 1 , R 2 , jωL, and (1/jωC). (c) Using these equations, obtain the values of the node voltages V a , V b and V c . (d) Hence obtain the values of the branch currents I 1 , I 2 , I 3 and I 4 . The various component values are given by: V S = 1 e j0 V, I s1 = 1 e j0 mA, I s2 = 2 e j0 mA , R 1 = 1k ohms, R 2 = 1.5 k ohms, jX 1 = j 1 k ohms, jX 2 = -j 1.5 k ohms. (8 marks) Fig.3. 4. Fig.4 shows an impedance-matching network for maximum power transfer. Fig.4. (a) Determine the value of R 2 that will make R L absorb maximum power. (b) What is the value of maximum power dissipated in R L ? The various component values are given by: n =2, v s = 20 cos(5000t) volts, R 1 = 8k ohms, R L = 19.2k ohms, L = 10 mH, C = 1 µF. (9 marks) Elec 275 – Principles of Electrical Engineering (Final) Fall 2012 3 of 6/- 5. Fig.5 shows a three-phase network. Calculate the complex power (P + jQ) in each of the impedances Z 1 , Z 2 and Z 3 . Fig.5. The various component values are given by: v s1 = 200 cos(377t) volts, v s2 = 200 cos (377t + 120 o ) volts, v s3 = 200 cos(377t + 240 o ) volts, Z 1 = (20 + j30) ohms, Z 2 = - j 40 ohms and Z 3 = 10 ohms. (Hint: use Ohms law and KVL ). (9 marks) 6. Consider the magnetic structure shown below. (a) Draw the analogous magnetic circuit, clearly showing the MMF, and its value, the flux φ and the reluctances. (b) Compute the total reluctance of the magnetic circuit. Neglect the fringing effect of the air-gap. (c) Determine the flux density (B) in the (metal) core when i = 8 A. (9 marks)

ELEC | 275 | Principles of Electrical Eng | homework | Elec 275 – Principles of Elect

19 PRE-LAB To be completed and submitted before performing Lab #1 Weight 20 % Question #1 (a) Physical representations of the digital multimeters (DMM) used in the lab (Fluke 8010A, Agilent 34405A) and a resistance element of unknown value are shown below. Also shown are power supply terminals from which a voltage is supplied. Show (by drawing lines) how yo

Experiment_1_-_Pre-Lab.pdf-PRE-LAB To be completed and submitted

Introduction: The objectives of this lab experiment were to to become familiar with the basic DC Current and Voltage measurements using Digital Multimeters (DMMs) - using the Fluke Model 8010A and the Agilent Model 34405A - as well as to become familiar with the sinusoidal AC waveform measurements using a Function Generator (FG) and a Digital- Storage-Os

Lab_Report_1.docx-Introduction: The objectives of this lab

Elec-275 Final Examination Winter 2013 Course Number Section Principles of Electrical Engineering ELEC 275 Examination Date Time # of pages Final Examination April 30 , 2013 3 Hours 6 Instructor(s) Dr. S.K.Das Materials allowed: x No Yes Calculators allowed: No x Yes Non-programmable University-approved calculators are allowed. Special Instructio

All courses in ELEC

Popular Documents