Chapter 19 POWERPOINT

Use the textbook to define these Technical Terms:

1. capacitor

2. diode

3. electric motor

4. electronic components

5. fuse

6. light emitting diode (LED)

7. liquid crystal display (LCD)

8. relay

9. resistor

10. semiconductor

11. solenoid

Use the textbook to answer these discussion questions:

1. Give an example of a photonic device on a car.

Read the chapter summary below:

Summary

■ A resistor limits current flow in a circuit. A fixed resistor has only one resistance value. A variable resistor can be changed to have various resistance values. A tapped resistor can be connected differently to change its internal resistance.

■ A switch connects and disconnects power to and from a circuit. Many different kinds of switches have been developed to meet different needs.

■ A capacitor is a storage device for electricity. It is commonly used to smooth current in a circuit.

■ Fuses are used to protect circuits from high current. Without a fuse, a short could cause enough current to burn up wires and components.

■ Circuit breakers are another form of circuit protection device. They also stop current if current draw becomes too high. However, circuit breakers are not ruined after one use.

■ A coil is an insulated wire wrapped in loops, usually around an iron-containing core.

■ A transformer uses two coils located close together. A transformer can isolate circuits, increase voltage, or decrease voltage.

■ A relay uses a small input current to control a larger circuit current.

■ A solenoid is an electromagnet used to move an iron plunger or core. It can be used to complete a very high-amperage circuit, something like a relay. It can also be used to engage parts—to move the engine throttle linkage, for example.

■ An electric motor uses magnetic forces to spin an armature. The spinning action can be used to do work.

■ Electrical and electronic symbols are used on wiring diagrams instead of isometric drawings of the individual parts. This saves time in creating the diagrams and makes the diagrams clear and easy to read.

■ Electronic devices are composed of semiconductor material, which allows the device to control electricity. Examples include diodes, transistors, solar cells, and integrated circuits.

■ A semiconductor is a substance that can change from an insulator to a conductor with external stimulation. A P-type semiconductor has more holes, which gives it a relatively positive charge N-type material has more electrons.

■ A diode passes current in one direction only.

■ Transistors switch or amplify current in a circuit.

■ Photonic semiconductors are devices that emit or detect light. They are used extensively in electronics to provide information and to produce direct current.