Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ OBJECTIVES After studying Chapter 3, the reader should be able to: 1.Prepare for ASE Electrical/Electronic Systems (A6) certification test content area “A” (General Electrical/Electronic System Diagnosis). 2.Define electricity. 3.Explain the units of electrical measurement. 4.Discuss the relationship among volts, amperes, and ohms. 5.Explain how magnetism is used in automotive applications.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Our universe is composed of matter, which is anything that has mass and occupies space. –The smallest particle that an element can be broken into and still retain the properties of that element is known as an atom. Electricity is the movement of electrons from one atom to another.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY FIGURE 3-1 In an atom (left), electrons orbit protons in the nucleus just as planets orbit the sun in our solar system (right).

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Positive and Negative Charges The parts of the atom have different charges. –The orbiting electrons are negatively charged, while the protons are positively charged. –Neutrons have no charge at all. FIGURE 3-2 The nucleus of an atom has a positive () charge and the surrounding electrons have a negative () charge.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Positive and Negative Charges In a normal, or balanced, atom, the number of negative particles equals the number of positive particles. –The number of neutrons varies according to the type of atom. FIGURE 3-3 A balanced atom.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Positive and Negative Charges The positive and negative charges within an atom are like the north and south poles of a magnet. –Charges that are alike will repel each other, similar to the poles of a magnet. FIGURE 3-4 Unlike charges attract and like charges repel.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Positive and Negative Charges When an atom is not balanced, it becomes a charged particle called an ion. Ions try to regain their balance of equal protons and electrons by exchanging electrons with neighboring atoms. FIGURE 3-5 An unbalanced, positively charged atom (ion) will attract electrons from neighboring atoms.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Electron Shells Electrons orbit around the nucleus in definite paths. These paths form shells, like concentric rings, around the nucleus. FIGURE 3-6 The hydrogen atom is the simplest atom, with only one proton, one neutron, and one electron. More complex elements contain higher numbers of protons, neutrons, and electrons.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Free and Bound Electrons The outermost electron shell or ring, called the valence ring, is the most important to our study of electricity. –When the valence ring has five or more electrons in it, it is fairly full. –The electrons are held tightly, and it is hard for a drifting electron to push its way into the valence ring.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Free and Bound Electrons These tightly held electrons are called bound electrons. FIGURE 3-7 As the number of electrons increases, they occupy increasing energy levels that are further from the center of the atom.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Free and Bound Electrons FIGURE 3-8 Electrons in the outer orbit, or shell, can often be drawn away from the atom and become free electrons.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Conductors Conductors are materials with fewer than four electrons in their atom’s outer orbit. FIGURE 3-9 A conductor is any element that has one to three electrons in its outer orbit.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Conductors FIGURE 3-10 Copper is an excellent conductor of electricity because it has just one electron in its outer orbit, making it easy to be knocked out of its orbit and flow to other nearby atoms. This causes electron flow, which is the definition of electricity.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Insulators Insulators are materials with more than four electrons in their atom’s outer orbit. FIGURE 3-11 Insulators are elements with five to eight electrons in the outer orbit.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Semiconductors Materials with exactly four electrons in their outer orbit are neither conductors nor insulators and are called semiconductor materials. FIGURE 3-12 Semiconductor elements contain exactly four electrons in the outer orbit.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY How Electrons Move Through a Conductor If an outside source of power, such as a battery, is connected to the ends of a conductor, a positive charge (lack of electrons) is placed on one end of the conductor and a negative charge is placed on the opposite end of the conductor. FIGURE 3-13 Current electricity is the movement of electrons through a conductor.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Conventional Theory versus Electron Theory It was once thought that electricity had only one charge and moved from positive to negative. The discovery of the electron and its negative charge led to the electron theory, which states that there is electron flow from negative to positive.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Conventional Theory versus Electron Theory FIGURE 3-14 Conventional theory states that current flows through a circuit from positive () to negative (). Automotive electricity uses the conventional theory in all electrical diagrams and schematics.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Amperes The ampere is the unit used throughout the world to measure current flow. FIGURE 3-15 One ampere is the movement of 1 coulomb (6.28 billion billion electrons) past a point in 1 second.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Amperes Amperes are measured by an ammeter (not ampmeter). FIGURE 3-16 An ammeter is installed in the path of the electrons similar to a water meter used to measure the flow of water in gallons per minute. The ammeter displays current flow in amperes.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Volts The volt is the unit of measurement for electrical pressure. Voltage is also called electrical potential, because if there is voltage present in a conductor, there is a potential (possibility) for current flow FIGURE 3-17 Voltage is the electrical pressure that causes the electrons to flow through a conductor.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Volts FIGURE 3-18 This digital multimeter set to read DC volts is being used to test the voltage of a vehicle battery. Most multimeters can also measure resistance (ohms) and current flow (amperes).

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Ohms Resistance to the flow of current through a conductor is measured in units called ohms. The resistance to the flow of free electrons through a conductor results from the countless collisions the electrons cause within the atoms of the conductor. FIGURE 3-19 Resistance to the flow of electrons through a conductor is measured in ohms.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ ELECTRICITY Watts A watt is the electrical unit for power, the capacity to do work. FIGURE 3-20 A display at the Henry Ford Museum in Dearborn, Michigan, that includes a hand-cranked generator and a series of light bulbs. This figure shows a young man attempting to light as many bulbs as possible. The crank gets harder to turn as more bulbs light because it requires more power to produce the necessary watts of electricity.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ SOURCES OF ELECTRICITY Friction When certain different materials are rubbed together, the friction causes electrons to be transformed from one to the other.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ SOURCES OF ELECTRICITY Heat When pieces of two metals are joined together at both ends and one junction is heated, current passes through the metals. FIGURE 3-21 Electron flow is produced by heating the connection of two different metals.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ SOURCES OF ELECTRICITY Light When certain metals are exposed to light, some of the light energy is transferred to the free electrons of the metal. FIGURE 3-22 Electron flow is produced by light striking a light-sensitive material.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ SOURCES OF ELECTRICITY Pressure When subjected to pressure, certain crystals, such as quartz, develop a potential difference, or voltage, on the crystal faces. FIGURE 3-23 Electron flow is produced by pressure on certain crystals.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ SOURCES OF ELECTRICITY Chemistry Two different materials (usually metals) placed in a conducting and reactive chemical solution create a difference in potential, or voltage, between them. –This principle is called electrochemistry and is the basis of the automotive battery.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ SOURCES OF ELECTRICITY Conductors and Resistance All conductors have some resistance to current flow. Several principles of conductors and their resistance include the following: –If the conductor length is doubled, its resistance doubles. –If the conductor diameter is increased, its resistance is reduced. –As the temperature increases, the resistance of the conductor also increases.. –Materials used in the conductor have an impact on its resistance.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ SOURCES OF ELECTRICITY Conductors and Resistance

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ SOURCES OF ELECTRICITY Resistors Resistance is the opposition to current flow. Most electrical and electronic devices use resistors of specific values to limit and control the flow of current.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ SOURCES OF ELECTRICITY Resistors FIGURE 3-24 A resistor color code interpretation.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ SOURCES OF ELECTRICITY Resistors FIGURE 3-25 A typical carbon resistor.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ SOURCES OF ELECTRICITY Variable Resistors Potentiometers are most commonly used as throttle position (TP) sensors on computer- equipped engines. Another type of mechanically operated variable resistor is the rheostat.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ SOURCES OF ELECTRICITY Variable Resistors FIGURE 3-26 A three-wire variable resistor is called a potentiometer. FIGURE 3-27 A two-wire variable resistor is called a rheostat.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ SUMMARY 1.Electricity is the movement of electrons from one atom to another. 2.Automotive electricity uses the conventional theory that electricity flows from positive to negative. 3.The ampere is the measure of the amount of current flow.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ SUMMARY 4.Voltage is the unit of electrical pressure. 5.The ohm is the unit of electrical resistance. 6.Sources of electricity include friction, heat, light, pressure, and chemistry.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ REVIEW QUESTIONS 1.Define electricity. 2.Define ampere, volt, and ohm. 3.List three materials that are conductors and three materials that are insulators. 4.List four sources of electricity.

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ CHAPTER QUIZ 1.An electrical conductor is an element with _____ electrons in its outer orbit. a)Less than 2 b)Less than 4 c)Exactly 4 d)More than 4

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ CHAPTER QUIZ 2.Like charges _____. a)Attract b)Repel c)Neutralize each other d)Add

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ CHAPTER QUIZ 3.Carbon and silicon are examples of _____. a)Semiconductors b)Insulators c)Conductors d)Photoelectric materials

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ CHAPTER QUIZ 4.Which unit of electricity does the work in a circuit? a)Volt b)Ampere c)Ohm d)Coulomb

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ CHAPTER QUIZ 5.As temperature increases _____. a)The resistance of a conductor decreases b)The resistance of a conductor increases c)The resistance of a conductor remains the same d)The voltage of the conductor decreases

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ CHAPTER QUIZ 6.The _____ is a unit of electrical pressure. a)Coulomb b)Volt c)Ampere d)Ohm

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ CHAPTER QUIZ 7.Technician A says that a two-wire variable resistor is called a rheostat. Technician B says that a three-wire variable resistor is called a potentiometer. Which technician is correct? a)Technician A only b)Technician B only c)Both Technicians A and B d)Neither Technician A nor B

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ CHAPTER QUIZ 8.Creating electricity by exerting a force on a crystal is called _____. a)Electrochemistry b)Piezoelectricity c)Thermoelectricity d)Photoelectricity

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ CHAPTER QUIZ 9.The fact that a voltage can be created by exerting force on a crystal is used in which type of sensor? a)Throttle position (TP) b)Manifold absolute pressure (MAP) c)Barometric pressure (BARO) d)Knock sensor (KS)

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ CHAPTER QUIZ 10.A potentiometer, a three-wire variable resistance, is used in which type of sensor? a)Throttle position (TP) b)Manifold absolute pressure (MAP) c)Barometric pressure (BARO) d)Knock sensor (KS)

Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ END