EET 101: Electric Circuit 1

1. EET 101: Electric Circuit 1 Scholl of Computer and Communication Engineering Semester 1: 2009/2010 Lecturer : (1) Amir Razif A. Jamil Abdullah amirrazif@unimap.edu.my Office: KKF 8A (2) Wan Nur Suryani Firuz Bt Wan Ariffin suryanifiruz@unimap.edu.my Office: KKF 8C Refference Book: 1. Fundamentals of Electric Circuits – Alexander sadiku (3rd edition) 2. Electric Circuits Fundamentals – FLOYD (7Th edition) 3. Basic Engineering Circuit Analysis – J.David Irwin & R.Mark Nelms( 9th edition)

2. Chap 1 : Circuit Elements and Variables Overview of circuit analysis, SI unit, voltage and currents, power, energy, elements on the circuit (passive and active) voltage and current source, Ohm’s Law, Kirchhoff’s Law, circuit model, circuit with dependent source. Chap 2 : Resistive Circuit Series / Parallel circuit, voltage divider circuit, current divider circuit, voltage and current measurement, Wheatstone Bridge, equivalent circuit for delta-wye (Pi-Tee). Chap 3 : Circuit Analysis Methods Introduction to the Node-Voltage Method, the Node-Voltage Method with dependent sources and special cases, introduction to Mesh-Current Method, Mesh-Current Method with dependent sources and special cases, source transformations, Thevenin and Norton equivalent circuit, maximum power transfer and superposition. Chap 4 : Inductance and Capacitance Inductor, relationship between voltage, current, power and energy, capacitor, relationship between voltage, current, power and energy, series-parallel combinations for inductance and capacitance. Syllabus - EET 101

3. Chap 5 : First-Order and Second-Order Response of RL and RC Circuit Natural response of RL and RC Circuit, Step Response of RL and RC Circuit, general solutions for natural and step response, sequential switching, introduction to the natural and step response of RLC circuit, natural response of series and parallel RLC circuit, Step response of series and parallel RLC circuit. Chap 6: Sinusoidal Steady-State Analysis The sinusoidal source, the sinusoidal response, the phasor and phasor diagram, the passive circuit elements in the frequency domain, impedances and reactances, Kirchhoff’s Laws in frequency domain, techniques of circuit analysis in frequency domain Chap 7 : Sinusoidal Steady-State Power Calculation Instantanenous power, average (active) and reactive power, the rms value power calculation, complex and power triangle , the maximum power transfer Chap 8 : Three Phase System Circuit Single and Three Phase System (Y and Δcircuit), balanced three phase voltage sources, Y – Y circuit analysis, Y - Δ circuit analysis, power calculation in three phase balanced circuit, average power measurement in three phase circuit. Syllabus - EET 101

4. COURSE STRUCTURE • Final Exam = 50% • Laboratory = 20% • Test (2 test) = 20% Test 1 – September 2009 Test 2 – October 2009 • Assignment = 10% Attandance, Quizes &Tutorial Total : =100%

5. Basic electric circuit concepts GOALS!! • Review SI • Know the definition of basic electrical quantities : voltage, current, and power • Know the symbols for and definition of independentand dependent sources • Be able to calculate the power absorbed by a circuit element using the passive sign convention

6. CIRCUIT ELEMENTS & VARIABLES • Overview of circuit analysis • SI unit • Voltage,currents, power, energy, • elements on the circuit (passive and active) voltage and current source • Ohm’s Law and Kirchhoff’s Law • circuit model • circuit with dependent source.

7. SI UNIT SI : International System of Unit is used by all the major engineering societies and most engineers throughout the world. • Unit SI

8. Standardized prefixes to signify powers of 10

9. CIRCUIT ELEMENTS & VARIABLES • Overview of circuit analysis • SI unit • Voltage, currents, power, energy, • elements on the circuit (passive and active) voltage and current source • Ohm’s Law and Kirchhoff’s Law • circuit model • circuit with dependent source.

10. ELECTRIC UNITS • Charge »»»Coulomb (C) • Current»»» Ampere (A) • Voltage»»» Volt (V) • Resistance»»» Ohm () • Power»»» Watt (W)

11. Electric charge is a property possessed by both electrons and protons. CHARGE (Q) Quantity is Base Unit is COULOMB (C) Examples of correct usage: Charge = 15 Coulombs Q = 15 C

12. CURRENT Current is the movement of charge in a specified direction.

13. Electric Current Terminology Quantity is CURRENT (I) Base Unit is AMPERE (A) An ampere equals a coulomb per second. Examples of correct usage: Current = 12 Amperes I = 12 A

14. Electric Current Relationships Q Charge Current = I = t Time Examples: Q 14 C =1.4 A = I = t 10 s Q 14 C =10 s = t = I 1.4 A

15. ex: Used to run refrigerator, stove, washing machine, and so on… ex batteries – used in automobiles or flashlight Types of current: DC AC Alternating current (arus ulangalik) Direct current (arus terus) Damped alternating current (arus ulangalik teredam) Exponential current

16. VOLTAGE Definition of Voltage • Voltage is the electric pressure or force that causes current. • It is a potential energy difference between two points. • It is also known as an electromotive force (emf) or potential.

17. Voltage Terminology Quantity is VOLTAGE(V) Base Unit is VOLT(V) A volt equals a joule per coulomb. Examples of correct usage: Voltage = 32 Volts V = 32 V

18. Voltage Relationships Energy W Voltage = V = Q Charge Examples: 56 J W =28 V = V = Q 2 C 84 J W =4 C = Q = V 21 V

19. RESISTANCE Definition of Resistance Resistanceis the opposition a material offers to current. Resistance is determined by: • Type of material (resistivity) • Temperature of material • Cross-sectional area • Length of material

20. Some Factors That Determine Resistance For a specific material and temperature, this block has given amount of resistance. Doubling the length of the block, doubles the resistance. Doubling the cross-sectional area, halves the resistance.

21. Resistance Terminology Quantity is RESISTANCE (R) Base Unit is OHM (W) Anohmequals a volt per ampere. Examples of correct usage: Resistance = 47 ohms R = 47 W

22. Resistance Relationships Resistivity x length KL Resistance = R = A area Example: 1.4 x10-6W·cm x 2 x104 cm KL = R = A 0.28 cm2 =0.1 W

23. ENERGY Work (W) The amount of work done equals the amount of energy used (converted). consists of a force moving through a distance. Energy (W) is the capacity to do work. Fifty joules of energy are required to do fifty joules of work. Thejoule (J) is the base unit for both energy and work.

24. POWER Definition of Power Poweris the rate of using energy or doing work. “Using energy”means that energy is being converted to a different form.

25. Power Terminology Quantity is POWER(P) WATT(W) Base Unit is A watt equals a joule per second. Examples of correct usage: Power = 120 Watts P = 120 W

26. Power Relationships Energy W Power = P = t Time Examples: 158 J W = 7.9 W = P = t 20 s 75 W x 25 s = W =Pt = 1875 J

27. CIRCUIT ELEMENTS & VARIABLES • Overview of circuit analysis • SI unit • voltage and currents, power, energy, • elements on the circuit (passive and active) voltage and current source • Ohm’s Law and Kirchhoff’s Law • circuit model • circuit with dependent source.

28. Circuit Elements • Active elements • capable of generating electric energy • Example : voltage and current sources • Passive elements • incapable of generating electric energy • Example : resistore, inductor, capacitor, diode and etc ACTIVE AND PASSIVE ELEMENTS

29. Independent source Current Voltage

30. Dependent source Voltage Current

31. Ideal voltage source connected in series

32. Ideal current source connected in parallel

33. Symbol of circuit elements • Resistor R UNIT: Ohm (Ω)

34. Resistor colour code

35. Yellow Violet Red Silver ±10 % 4 7 00 Resistor Colour Codes

36. Resistor Colour Codes Gold = ± 5 % Green = 5 Blue = 6 Orange = 3 56 x 103±5 % = 56000 ±5 % = 56 kW ±5 %

37. Resistor Colour Codes = 464 kW ± 2% 4 6 4 0 0 0 ± 2%

38. Conductance • Conductance is a measure of the ability of an element to conduct electric current • Inverse of resistance • Units: Siemens (S) or mhos

39. Capacitor C UNIT: Farad (F)

40. Inductor L UNIT: Henry (H)

41. CIRCUIT ELEMENTS & VARIABLES • Overview of circuit analysis • SI unit • voltage and currents, power, energy, • elements on the circuit (passive and active) voltage and current source • Ohm’s Law and Kirchhoff’s Law • circuit model • circuit with dependent source.

42. Short Circuit • R = 0  no voltage difference exists • all points on the wire are at the same potential. • Current can flow, as determined by the circuit

43. Open circuit • R =   no current flows • Voltage difference can exist, as determined by the circuit

44. Circuit Nodes and Loops • A node is a point where two or more circuit elements are connected. • A loop is formed by tracing a closed path in a circuit through selected basic circuit elements without passing through any intermediate node more than once

45. + - Example: Find the Nodes Vs node

46. Example: Find the loops loop

47. OHM LAW • George Simon Ohm (1787-1854) formulated the relationships among voltage, current, and resistance as follows: The current in a circuit is directly proportional to the applied voltage and inversely proportional to the resistance of the circuit.

48. KIRCHHOFF LAW • Gustav Robert Kirchhoff (1824 – 1887) • Models relationship between: • circuit element currents (KCL) • circuit element voltages (KVL) • Introduce two laws: • Kirchhoff Current Law (KCL) • Kirchhoff Voltage Law (KVL)

49. Kirchhoff’s Current Law (KCL) • Current entering node = current exiting(What goes in, must come out) • Convention: +i is exiting, -i is entering • For any circuit node:

50. Kirchhoff’s Current Law (KCL) No matter how many paths into and out of a single point all the current leaving that point must equal the current arriving at that point.