2. Bell Ringer R30 What do you think a circuit looks like if you would draw a picture? Include in picture: battery, wires, and a lightbulb.

3. Definitions Voltage: Electric Potential – separate + and - charges V (volts) = Joules/Coulomb – J/C One volt = one coulomb of charge gains or loses one joule of energy

4. Simple Circuits Whenever you separate + and – charges, you create potential difference. Potential difference is measured in volts (V) gives electrons an electric potential energy ex. battery, solar panel

5. Electric Potential Which is worse, 120 volts or 25,000 volts? It depends…. Energy causes pain… not voltage Voltage is potential energy per charge (q) volt = Energy / Charge so Energy =Volt x Charge

6. Example Electric Potential = Voltage Basic outlet is 120 V The flow of an outlet is about 20 Coulombs/sec The energy released in 1 sec would be: Amount of energy to lift 75 gal of water 1 m high!

7. Simple Circuits When separated, - charges will try to flow towards + charges. This flow is called current (I) In a battery, electrons will always flow from the – terminal to the + terminal if they are given a path. o ex. wire

8. Simple Circuits You can put a device into this wire that changes the voltage to another form of energy. These devices are called resistors Resistors can convert electric energy into: light (ex. lightbulb) heat (toaster) motion (motor)

9. Simple Circuits Most resistors convert electric potential energy into more than one type of energy ex. Light bulbs also give off heat toaster wires glow (light)

10. + + + - - - INSULATORINSULATOR As long as the electrons can move from the negative to the positive, you have a circuit.

11. Simple Circuits Electrons only flow when a circuit is a closed loop

12. Ohm’s Law Water Circuit Analogy Potential Difference (Voltage) amount of water (pressure)

13. Voltage would be the water pressure. Think of a geyser as high voltage, and the shower of a low-rent apartment on the fifth floor as low voltage HIGH low

14. Ohm’s Law Water Circuit Analogy Switch turns flow on and off

15. Ohm’s Law Water Circuit Analogy Resistance thickness & length of hose

16. Ohm’s Law Water Circuit Analogy Current rate of flow