1. Electric Circuits and Power Page 706

2. Ohm’s Law Resistance is equal to the voltage divided by the current. Resistance = Voltage Current Ohms ( ) = Volts (V) Amps (A) Voltage = Current X Resistance

3. Features of a Circuit 1.Circuits have devices (LOAD)` that are run by electrical energy. 2.A circuit has a source of electrical energy. 3.Circuits are connected by conducting wires.

4. Series Circuit In a series circuit, there is only one path for the current to take. Advantages – simple to design and build Disadvantages – If one light goes out, they all go out; as more lights are added, they become dimmer.

5. Ammeter A device used to measure current.

6. Parallel Circuit In a parallel circuit, there are several paths for current to take. Advantages – if there is a break in one branch, charges can still move through the other branches; switches can be added to turn on different parts; as new branches are added, resistance decreases & current increases. Disadvantages – More difficult and complicated to assemble.

7. Voltmeter A device used to measure voltage, or electrical potential energy difference.

8. Power The rate at which energy is transformed from one form to another. The unit of power is the watt (W).

9. Calculating Power Power = Voltage X Current Watts = volts X amperes P=VI Energy = Power X Time