Basic electrical engineering

Circuit Analysis I OR Basic electrical engineering Course Code EEN111 Pre-requisite None Credit Hours 3+1 Assignments + Quizzes 25% Midterm Examination 25% Final Examination 50% Floyd: Principles of Electric Circuits (Edition: 6th) Robert L. Boylestad: Introductory Circuit Analysis William H. Hayt: Engineering Circuit Analysis (Current Edition: 6th) B.L. Theraja / A.K Theraja: A Text Book of Electrical Technology Schaum’s Outline Series: Basic Electrical Engineering

Course Outline Electrical components Electrical quantities and measurements Resistor networks Kirchhoff's Laws Power sources Theorems: Norton, Thevenin and superposition Delta-Star networks AC analysis and phasors Capacitors and Inductors RL, RC, RLC circuits and impedance analysis

Today’s Menu Electronic components Passive/Active components Charge Voltage Current Units Scientific notation and Metric system of units Unit conversions

Electronic Components An electronic component is any basic discrete device or physical entity in an electronic system used to affect electrons or their associated fields. Two main types: Active Passive Electronic Components

Passive electronic components Cannot increase power or voltage level of a signal, hence cannot inject energy into the circuit.

Active electronic components Can inject power into a circuit by itself or using another power source and hence can amplify a signal or change its power/voltage level.

Charge Can be positive (e.g. proton) or negative (e.g. electron) There is a force between charges Like Charges: repel (e.g. two electrons) Unlike Charges: Attract (e.g. an electron and a proton) Unit of charge is a coulomb Massive unit: charge of an electron = 1.602 × 10-19 coulombs Find the number of electrons required to have a charge of 1C? 6.24 × 1018

Electric current Current (I) is the amount of charge (Q) that flows past a point in a unit of time (t). One ampere is a number of electrons having a total charge of 1 C move through a given cross section in 1 s. What is the current if 2 C passes a point in 5 s? 0.4 A

Voltage Voltage (V) is the work (W) done per unit charge (Q); it is responsible for establishing current. Work is done as a charge is moved in the electric field from one potential to another. What is the applied voltage if 2 J of work is done on 0.5 C of charge to drive it between two points? 4 V

Voltage is responsible for establishing current. One volt is the potential difference (voltage) between two points when one joule of work is used to move one coulomb of charge from one point to the other. Voltage is responsible for establishing current.

Basic Units Quantity Unit Symbol length meter kilogram second ampere Kelvin candela mole m kg s A K cd mol mass time electric current temperature luminous intensity amount of substance

Some Important Electrical Units Except for current, all electrical and magnetic units are derived from the fundamental units. Current is a fundamental unit. current charge voltage resistance power ampere coulomb volt ohm watt A C V W Quantity Unit Symbol

Scientific and Engineering Notation Very large and very small numbers are represented with scientific and engineering notation. 47,000,000 = 4.7 x 107 (Scientific Notation) = 47.0 x 106 (Engineering Notation) 0.000 027 = 2.7 x 10-5 (Scientific Notation) = 27 x 10-6 (Engineering Notation)

Engineering Metric Prefixes Large numbers Small numbers peta tera giga mega kilo 1015 1012 109 106 103 P T G M k 10-3 10-6 10-9 10-12 10-15 milli micro nano pico femto m n p f

Metric Conversions Smaller unit 0.47 MW = 470 kW Larger number When converting from a larger unit to a smaller unit, move the decimal point to the right. Remember, a smaller unit means the number must be larger. 0.47 MW = 470 kW Larger number Smaller unit

Metric Conversions Larger unit 10,000 pF = 0.01 mF Smaller number When converting from a smaller unit to a larger unit, move the decimal point to the left. Remember, a larger unit means the number must be smaller. 10,000 pF = 0.01 mF Smaller number Larger unit

Metric Arithmetic 10,000 W + 22 kW = ? 10,000 W + 22,000 W = 32,000 W When adding or subtracting numbers with a metric prefix, convert them to the same prefix first. 10,000 W + 22 kW = ? 10,000 W + 22,000 W = 32,000 W 10 kW + 22 kW = 32 kW Alternatively,

Selected Key Terms Engineering notation Exponent Metric prefix Scientific notation A system for representing any number as a one-, two-, or three-digit number times a power of ten with an exponent that is a multiple of three. The number to which a base is raised. A symbol that is used to replace the power of ten in numbers expressed in scientific or engineering notation. A system for representing any number as a number between 1 and 10 times a power of ten.

Quiz 1. A resistor is an example of a. a passive component b. an active component c. an electrical circuit d. all of the above

Quiz 2. The electrical unit that is fundamental is the a. volt b. ohm c. coulomb d. ampere

Quiz 3. In scientific notation, the number 0.000 56 is written a. 5.6 x 104 b. 5.6 x 10-4 c. 56 x 10-5 d. 560 x 10-6

Quiz 4. In engineering notation, the number 0.000 56 is written a. 5.6 x 104 b. 5.6 x 10-4 c. 56 x 10-5 d. 560 x 10-6

Quiz 5. The metric prefix nano means a. 10-3 b. 10-6 c. 10-9 d. 10-12

Quiz 6. The metric prefix pico means a. 10-3 b. 10-6 c. 10-9 d. 10-12

Quiz 7. The number 2700 MW can be written a. 2.7 TW b. 2.7 GW c. 2.7 kW d. 2.7 mW

Quiz 8. The value 68 kW is equal to a. 6.8 x 104 W b. 68, 000 W c. 0.068 MW d. All of the above

Quiz 9. The sum of 330 mW + 1.5 W is a. 331.5 mW b. 3.35 W c. 1.533 W d. 1.83 W

Quiz 10. The quantity 200 mV is the same as a. 0.000 200 V b. 20 mV c. 0.2 V d. all of the above

Quiz Answers: 1. a 2. d 3. b 4. d 5. c 6. d 7. b 8. d 9. d 10. c