Unformatted text preview: EE1002 Practice questions 1. An incandescent light bulb rated at 60W will dissipate 10W as heat and light when connected across a 100V ideal voltage source. Similarly a 100W light bulb will dissipate 100W when connected to the same source. If the bulbs are connected in series, determine the power that either one of the two bulbs will dissipate. 2. With no load attached, the voltage at the terminals of a particular power supply is 50.8V. When a 10‐W load is attached, the voltage drops to 49V. a) Determine the v s and Rs for this nonideal source. b) What voltage would be measured at the terminals in the presence of a 15 resistor? c) How much current could be drawn from this power supply under short‐circuit condition? 3. Assume R0 2, R1 1, R 2 4 / 3, R3 6., and Vs 12V in the circuit. a) Find ia , ib , ic . b) The current through each resistance. 1 4. Determine the equivalent resistance of the infinite network of resistors in the circuit. 5. A practical volt meter has an internal resistance rm . What is the value of rm if the meter reads 11.81V when connected as shown in the circuit. 6. Determine the voltge “gain” Av v 2 v1 in the amplifier circuit. 2 7. Find the Thevenin equivalent circuit for the circuit between nodes a and b. 8. Compute the Norton’s equivalent of the circuit between nodes a and b. 9. Find the voltage v across the 0.25 resistance. 3 '
10. Determine the node voltages v1' , v 2 and v3 with respect to v n . 11. Find the Thevenin equivalent resistance seen by the load resistor R L in the circuit. 4 12. Find the energy stored in each capacitor and inductor under steady‐state condition, in the circuit. 13. Determine Vo in the circuit if v1 4 cos1000t V
6 L 60mH , C 12.5F R L 120 5 14. The circuit is a simple model of an automotive ignition system. The switch models the ‘points’ that switch electric power to the cylinder when the fuel‐air mixture is compressed. And R is the resistance between the electrodes (I.e. the gap) of the spark plug. Determine the value of L and R1 so that the voltage across the spark plug gap just after the switch is changed is 23kV and so that this voltage will change exponentially with a time constant 13ms. VG 12V , RG 0.37, R 1.7k 15. In the circuit determine the current I and the voltage V AB for each of the cases R 2, 0, 6 . 6 16. In the circuit determine the voltage across the terminals X and Y when (a) they are on open‐
circuit, (b) they are short‐circuited and (c) a resistor R is connected across them. Determine also the current I for all the three cases. 17. Determine the current gain Ai iload
. iin 7 18. In the circuit with the switch is closed, the ammeter AM reads 3A. Predict ammeter reading with the switch S open. Use Norton’s theorem. 19. Determine the voltage Vo in the circuit. 20. Determine the Thevenin and Norton equivalent circuits between a and b. 8 21. Determine the maximum power delivered to the load resistor R L . 22. Determine the time domain waveforms of the following phasors. V 230 120 0 230120 0
I 1530 0 15150 0 23. Plot i vs v to scale for each of the parts. 9 24. Draw a circuit that contains a 5 resistor, 10V voltage source, a voltage controlled voltage source having a gain constant of 0.5. Assume that the voltage across the resistor is the control voltage for the controlled source. Place all the elements in series. 25. For the circuit, solve for i s . 26. Find the equivalent resistance of the network. 1 0 27. Find the voltage V AB in the circuit. 28. Assume that the switch was closed for a long time prior to t 0. Find expression for v(t ) after the witch is opened. 1 1 ...
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This note was uploaded on 12/13/2011 for the course ELECTRICAL EE1002 taught by Professor Panda during the Spring '11 term at National University of Singapore.
- Spring '11