1. Circuit Electricity

2. Electric Circuits The continuous flow of electrons in a circuit is called current electricity. Circuits involve… –Energy source, conductor and load

3. Electrochemical Cells A battery is a combination of electrochemical cells –Electrochemical cells are packages of chemicals that convert chemical energy into electrical energy –Electrolyte – liquid or paste that conducts electricity because it contains chemicals that form ions. –Electrodes – metal strips that react with the electrolyte –Chemical reaction allows electrons to collect on one of the electrodes making it negatively charged.

4. Electrochemical Cells Wet cell – uses a liquid electrolyte

5. Electrochemical Cells Dry cell – uses a paste electrolyte –Schematic diagram of a rechargeable lithium-ion cell. –During charging, lithium ions flow to the negative electrode through the electrolyte and electrons flow from the external circuit. –During discharge the directions are reversed, generating useful power to be consumed by the device.

6. Potential Difference Potential Energy is energy stored in an object The difference in electrical potential energy between two points in a circuit is called the potential difference –This is also known as voltage and can be measured using a voltmeter using the units of volts (V).

7. Current Electric Current is a measure of the amount of electric charge that passes a point in an electric circuit each second. –Current is measure in amperes (A) using an ammeter

8. Resistance Degree to which a substance opposes flow of electric current through it. –Measured in ohms (Ω) using an ohmmeter. This resistance slows down the flow of electrons and therefore it slows down the current and converts electrical energy into other forms of energy