ELECTRICAL CIRCUITS All you need to be an inventor is a good imagination and a pile of junk. -Thomas Edison

The unit for the rate of current is the ampere or amp Electric current Electric Currents is The rate at which electrons pass through a wire at a given point To produce a current, electrons need to move continuously from one place to another. The unit for the rate of current is the ampere or amp

High current The higher the current, the greater the number of charges that pass through the point each second CURRENT

Low current The lower the current, less charges that pass through the point each second CURRENT

I Love Lucy shows us how current works! Current example… I Love Lucy shows us how current works! I Love Lucy

Current example… electric, current, circuit, high, low Talk with a partner: What is electric current? When was the current the slowest in the movie? When was the current the fastest in the movie? Words I want to hear in your conversations: electric, current, circuit, high, low

All simple circuits need three basic parts: An energy source Wires A load

Load The load changes electrical energy into other forms of energy These other forms might include thermal energy, light energy, or mechanical energy Look at Figure 1 on the bottom of page 436. What are examples of loads in the picture? Light bulbs Appliances Televisions Motors

Energy source Look at Figure 1 on page 436. The energy source is what gives the circuit its energy or power What are examples of energy sources? Batteries Photocells Thermocouples Electric generator at a power plant

Batteries Batteries use chemical energy to generate electrical energy for an electric circuit.

Photocells Photocells use the sun’s light (solar energy) to generate electrical energy for an electric circuit

Electric generator at a power plant Every time you plug something into an outlet, chances are that the electricity was generated at a coal-powered power plant!

A complete, unbroken path through which electric charges can flow Electric circuit A complete, unbroken path through which electric charges can flow If the circuit is broken, the charges can’t flow continually!

ELECTRICAL CIRCUITS Open Circuit: leaves gaps in a circuit preventing electrons from traveling from one side of the power source to the other. Thus, no current will flow. Point of open In this circuit the lamp will not illuminate because there is no complete pate for current to flow.

Electric circuit A closed circuit (on) switch means that there is no gaps in the circuit allowing the electrons to flow through the entire circuit. Thus, you have a closed circuit (a circuit with no gaps in it). Current flows from the positive side of the power source wired into the circuit and back to the negative side of the power source.

A Switch to Control a Circuit A switch is used to open and close a circuit For charges to flow through a circuit, the switch must be closed, or turned “on” When the switch is open, or “off,” the loop of the circuit is broken. Charges cannot flow through a broken circuit. Light switches, power buttons, and even keys on calculators can open and close circuits.