Electricity and Electrical Circuits

Chapter Sections O 1 - Electrical Circuits O 2 - Current and Voltage O 3 - Resistance and Ohm’s Law

1 - Electrical Circuits Electrical Current O The flow of electricity through wires, motors, light bulbs, and other devices O Typically the flow of electrons O Very dangerous – your nerves use electricity to function

Electrical Circuits O A complete path through which electricity travels O Wires in circuits are like pipes that carry water

Electrical Symbols O Circuit diagrams use symbols to make drawing circuits simpler and easier

Open and Closed Circuits O Open circuit has a break which stops the flow of electricity O Closed circuit has no breaks O Switches and Circuit Breakers open and close a circuit

2 - Current and Voltage Current O Current is measured in amperes (A) O Current flows from positive to negative O Current is the flow or motion of charges

Measuring current O Measured with an ammeter O The current must pass through the meter O Can be either AC or DC, which we will learn about in Chapter 14

Voltage O Measured in volts (V) O Measures electrical potential energy O A higher potential difference (more volts) means that more work can be done

Measuring Voltage O Measured with a volt meter O A multimeter can measure voltage, current, and resistance

Batteries O Use chemical energy to create voltage.

3 - Resistance and Ohm’s Law Resistance O The measure of how strongly a wire or other object resists current flowing through it

Measuring Resistance O Measured in ohms ( Ω = omega)

Ohm’s Law

Using Ohm’s Law

Conductors and Insulators O Electricity flows easily through conductors O Electricity is blocked by insulators O Materials in between these two are called semiconductors

Potentiometers O A potentiometer is a variable resistor that is used to control the flow of current O Dimmer switches and volume controls are examples