1. Electric Circuits

2. Electric Current – the movement or flow of electric charges from one place to another. Electric Circuit – a controlled path in which electric current passes through. Electric circuits are used to convert electrical energy into other forms of energy such as heat or light.

3. Circuits A simple circuit diagram often looks like a rectangle. It shows how the loads, batteries, wires and switches are linked together and how the circuit is organized.

4. The Parts of an Electric Circuit

5. 3. Electric Circuit Control Device – a switch that controls the electricity (turn on and off). 4. Connectors – the conducting wires that provide the controlled path for electric current to flow to each part of the circuit. 1. Source of electrical Energy – the place or thing that generates the electrical energy. 2. Electrical Load – anything that converts electrical energy into the form of energy needed.

6. Movement in a Circuit The movement in a circuit is continuous and controlled. A battery serves as a source of energy for a circuit. The electrical energy stored in the battery is called electrical potential energy. The electrons have the potential for doing work but are unable to do it until the battery is connected to the load and the circuit is closed.

7. Closed Circuit – a circuit that is “on” or allowing electricity to flow through. Open Circuit – a circuit that is “off” or not allowing electricity to flow through.

8. Electric current flows in a continuous loop from the negative terminal of the cell, through the wires, the switch, and the electric load (light), and returns to the cell’s positive terminal. How Current Flows Through a Circuit

9. Types of Circuits There are 2 types of circuits: –Series Circuit: A circuit with only one path for current to flow –Parallel Circuit: A circuit with many pathways for current to flow.

10. Series Circuits In a series circuit electrons travel around one closed loop. The current at any one point in a series is exactly the same as the current at any other point. The charges pass from one load to the next before returning to the power source to be energized again.

11. Series Circuit

12. Parallel Circuits In a parallel circuit charges flow around two or more different loops. After leaving the power source they eventually reach a “fork in the road”. Some charges take one path while other charges take another path. The current in a parallel circuit is not the same at every point in the circuit.

13. Parallel Circuits

14. Sample Question Draw a circuit in series with a battery, an ammeter, and a light bulb.

16. Sample Question 1.Find the resistance of the light bulb in this circuit. The cell is 6 V, and the ammeter is reading 100 mA.

17. Answer 1.Convert 100 mA to A by dividing by 1000 100/1000 = 0.1A 2.Use Ohm’s Law to find resistance: V = IR so R = V/I 3.Sub in values: V = 6V, I = 0.1A R = 6V/0.1A R = 60 Ω