AUT 242 Automotive Electricity II. Chapter 3, Fundamentals. OBJECTIVES. After studying Chapter 3, the reader should be able to: Prepare for ASE Electrical/Electronic Systems (A6) certification test content area “A” (General Electrical/Electronic System Diagnosis). Define electricity.
Chapter 3, Fundamentals
After studying Chapter 3, the reader should be able to:
In an atom (left), electrons orbit protons in the nucleus just as planets orbit the sun in our solar system (right).ELECTRICITY
Electrons in the outer orbit, or shell, can often be drawn away from the atom and become free electrons.
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
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.ELECTRICITYConventional Theory versus Electron Theory
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).ELECTRICITYVolts
FIGURE 3-19 Resistance to the flow of electrons through a conductor is measured in ohms.
FIGURE 3-21 Electron flow is produced by heating the connection of two different metals.
FIGURE 3-22 Electron flow is produced by light
striking a light-sensitive material.
FIGURE 3-24 A resistor color code interpretation.
A typical carbon resistor. to test the voltage of a vehicle battery. Most multimeters can also measureSOURCES OF ELECTRICITYResistors
A three-wire variable resistor is called a potentiometer.
A two-wire variable resistor is called a rheostat.
2. Like charges _____.
3. Carbon and silicon are examples of _____.
4. Which unit of electricity does the work in a circuit?
5. As temperature increases _____.
6. The _____ is a unit of electrical pressure.
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?
8. Creating electricity by exerting a force on a crystal is called _____.
9. The fact that a voltage can be created by exerting force on a crystal is used in which type of sensor?
10. A potentiometer, a three-wire variable resistance, is used in which type of sensor?