1. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 1 FIGURE 3-1 In an atom (left), electrons orbit protons in the nucleus just as planets orbit the sun in our solar system (right).

2. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 2 FIGURE 3-2 The nucleus of an atom has a positive (+) charge and the surrounding electrons have a negative (-) charge.

3. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 3 FIGURE 3-3 A balanced atom.

4. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 4 FIGURE 3-4 Unlike charges attract and like charges repel.

5. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 5 FIGURE 3-5 An unbalanced, positively charged atom (ion) will attract electrons from neighboring atoms.

6. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 6 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.

7. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 7 FIGURE 3-7 As the number of electrons increases, they occupy increasing energy levels that are further from the center of the atom.

8. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 8 FIGURE 3-8 Electrons in the outer orbit, or shell, can often be drawn away from the atom and become free electrons.

9. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 9 FIGURE 3-9 A conductor is any element that has one to three electrons in its outer orbit.

10. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 10 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.

11. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 11 FIGURE 3-11 Insulators are elements with five to eight electrons in the outer orbit.

12. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 12 FIGURE 3-12 Semiconductor elements contain exactly four electrons in the outer orbit.

13. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 13 FIGURE 3-13 Current electricity is the movement of electrons through a conductor.

14. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 14 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.

15. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 15 FIGURE 3-15 One ampere is the movement of 1 coulomb (6.28 billion billion electrons) past a point in 1 second.

16. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 16 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.

17. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 17 FIGURE 3-17 Voltage is the electrical pressure that causes the electrons to flow through a conductor.

18. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 18 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).

19. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 19 FIGURE 3-19 Resistance to the flow of electrons through a conductor is measured in ohms.

20. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 20 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.

21. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 21 FIGURE 3-21 Electron flow is produced by heating the connection of two different metals.

22. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 22 FIGURE 3-22 Electron flow is produced by light striking a light-sensitive material.

23. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 23 FIGURE 3-23 Electron flow is produced by pressure on certain crystals.

24. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 24 FIGURE 3–24 This figure shows a resistor color-code interpretation.

25. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 25 FIGURE 3-25 A typical carbon resistor.

26. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 26 FIGURE 3-26 A three-wire variable resistor is called a potentiometer.

27. Diagnosis and Troubleshooting of Automotive Electrical, Electronic, and Computer Systems, 6/e - By James D. Halderman Copyright © 2012, 2010, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 27 FIGURE 3-27 A two-wire variable resistor is called a rheostat.