# Electrical Technology

Topics: Electric current, Electrical resistance, Electrical impedance Pages: 40 (9993 words) Published: December 20, 2012
Objective – Chapter 11
1.0 INTRODUCTION TO ELECTRICAL CIRCUITS2
Basic Quantities and Units in Electrical2
Quantities2
Units3
Factors Affecting Resistance4
Length of the Conductor:4
Area of Cross-Section of the Conductor:4
Electrical Resistivity of Substances5
Effect of Temperature5
Components of Electrical Circuits6
Components of an Electric Circuit7
Measuring Current, Voltage and Resistance8
Measuring voltage8
Measuring current9
Measuring resistance9
Ohm's Law, Electricity10
Definition of Ohm11
Unit of resistance is 'ohm'11
Statement of Ohm's Law11
Ohm’s law : Current13
Ohm’s Law : Voltage13
Ohm’s Law : Resistance13
Ohm’s Law : Formula Transformation14
Electric Power and Its Derivation15
DC POWER: DC Power V and I.15
Problems - Electrical Power16
Answers to Problems - Electrical Power16
Electricity Unit Measure (Electrical energy)17
Heating effect of electricity17
SERIES AND PARALLEL RESISTORS:17
Series Resistors.18
Two Resistors in Parallel.18
Three or more Resistors in Parallel.19
SERIES / PARALLEL RESISTORS:19
DC VOLTAGE: Voltage Divider.21
Problems - The Potential Divider22
Answers to Problems - The Potential Divider23
DC CURRENT: Current Divider.24
Problems - The Current Divider25
Answers to Problems - The Current Divider25
Kirchhoff's Laws26
Kirchhoff's Current Law27
The algebraic sum of current into any junction is zero.27
Kirchhoff's Current Law in action27
i2 + i3 = i1 + i427
Kirchhoff's Voltage Law28
Positive and Negative Signs in Kirchhoff's Voltage Law28
Kirchhoff's Voltage Law in action28
Problems - Kirchoff's Laws30
Answers to Problems - Kirchoff's Laws31
Exercise33
CHAPTER 237
37
INDUCTOR, CAPACITOR AND ALTERNATING CURRENT37
Objective – Chapter 237
INDUCTOR38
Basic principles of inductors38
Inductance39
Principles of Electromagnetic Induction39
SELF-INDUCTION40
Inductive reactance (XL ) and the factors affecting inductive reactance40
Inductors In Series.41
Inductors in Parallel.41
Storing Energy in an Inductor.42
Capacitor43
Basic principles of capacitors43
Units of Capacitance44
PARALLEL PLATE CAPACITOR44
Parallel Capacitors44
Series Capacitors45
Effects of capacitors in electrical circuits47
Energy Storage47
Alternating Current Circuits48
AC basic circuits characteristic48
AC THEORY: AC Ohm's Law.48
AC THEORY: Voltage and Current for R.49
AC THEORY: Voltage and Current for C.49
AC THEORY: Voltage and Current for L.50
AC VOLTAGE AND CURRENT: Resistor, Voltage and Current Relationship.50
AC VOLTAGE AND CURRENT: Capacitor, Voltage and Current Relationship.51
AC VOLTAGE AND CURRENT: Inductor, Voltage and Current Relationship.52
AC VOLTAGE AND CURRENT: Series RCL Voltage Current Relationships52
AC VOLTAGE AND CURRENT: Angle of Rotation.53
THREE PHASE SYSTEM55
THREE PHASE SYSTEM (3)55
Simple three phase transmission57
Differentiate between three phase system and single phase system58

Objective – Chapter 1

Upon completion of this topic, student should be able to:
* Classify basic electrical Quantities (units and symbols) * Classify types of electrical circuits
* Classify Ohm’s Law
* Classify Electrical Power
* Classify Electrical Energy
* Classify the characteristic of series and parallel circuits * Explain Kirchhoff’s Law in complex electrical circuits

1.0 INTRODUCTION TO ELECTRICAL CIRCUITS
Basic Quantities and Units in Electrical
Quantities
The table shows electrical quantities which are used in electronics. The relationship between quantities can be written using words or symbols (letters), but symbols are normally used because they are much shorter; for example V is used for voltage, I for current and R for resistance: As a...