FIRST YEAR ELECTROMECHNICAL ENGINEERING BASICS ELECRICAL ENGINEERING UNIVERSITY OF TECHNOLOGY ELECROMECHNICAL DEPARTMANT SYSTEMS BRANCH Question Sheet (2) Dr. Sameir Abd Alkhalik Aziez 1. (Figures 1, 2, & 3) Find the potential at point P relative to ground. (22.8 V; -3.1 V; 5 V) 2. (3) Find the source & ground currents. (3A; 2A; 1A) 3. (4) Find the values, of E and R. (10 V; 4 ohms) 4. (6) Given that V = 24 Volts, find E. (148 V). 5. (7) Find the applied voltage V and current I. (24 V; 10 A) 6. (9) Find the current in the 9 mV source, 7. (10) Find the current in the 240 V source. 8. (18) If I = 0, what is R? (0.5 micro-amps) (0.576 A) (23.75 ohms) 9. (11) Find all source currents. (1 A; 3 A; 4 A) 10. (12) Find the current in the 6 ohm resistor. (2.1 A) 11. (13) Find the current in the 60 V source, the voltage across the 12 A source, and the potential to ground at P. (1 A; 70 V; -30 V) 12. (16) Find the current in the 12 V source. (1 A) 13. (5) The resistors R1 , R2 , and R3 have the values R, R, and 2R respectively, the total input power is 30 W. Find the power dissipated in each of the resistors. Also find the percent increase in input power when the applied voltage is increased by 20 %. (18 W; 8 W; 4 W; 44 %) 14. (8) With the switch in position 1, the ammeter reads 1.46 A and the voltmeter reeds 2.35 V. In position 2, the readings are 1.25 A and l.0 V. Find the ammeter resistance and the supply voltage Vs. (0.8 ohms; 3.518 V) 15. (8) Continue question 14 to find the voltmeter resistance and the resistance R. (11.2 ohms; 1.88 ohms) 16. (5) The resistors R1, R2, and R3 have the values 100, 200, and 470 K-ohms respectively. They ere rated at 1.0 W, 0.5 W, and 0.5 W respectively. Find the maximum permissible voltage V. (553 V) -1- 17. (17) Find the currents in the 8 ohm resistor and in the sources. ( 1A; 3.6 A; 19A; 14.6 A ) I8. (14) Find the value of the resistance R. (1.0 ohms) 19. (15) Find the value of the resistance R. (1.67 ohms) 20. (4) Assume the current in the 42 V source is not given; show that it must be 3 A. 21. (15) Assume the current in the 5 ohm resistor is not given; show that it must be 2 A. NB: In the circuit diagrams, all resistance values ore in ohms. -2- 6 1 2 7 3 8 4 9 10 5 -3- 11 15 ٥ 12 16 ١ ٦ ٦ ٦ ٦ 13 ٦ 17 ١ 7 14 18 ١ ٨ -4-