1. Electrical Engineering

2. A circuit is a combination of different components that allow electricity to flow through them. Each component serves its own purpose. The electricity that flows through the circuit can either be DC (direct) and flow in one direction (eg. Battery) or it can be AC (alternating) and flow back and forth. http://www.youtube.com/watch?v=JZjMuIHoBeg http://www.youtube.com/watch?v=JZjMuIHoBeg

3. Each part of the circuit serves a function. There are four main functions: 1.Power supply 2.Conduction, insulation and protection 3.Control 4.Transformation of energy

4. 1.Power Supply All circuits need a source of electricity. Some sources of electricity are: Batteries Electrical outlets Photovoltaic cells

5. 2. Conduction, insulation and protection Any component that allows electricity to flow from part to another performs the function of conduction. Ex. : wires in a circuit Any component that prevents electricity to flow from part to another performs the function of insulation. Ex. : plastic casing around wires Any component that can cut the flow of electricity in case of a power surge performs the function of protection. Ex. : a fuse

7. 3. Control A switch is the main type of component that serves as a control in an electrical circuit. If the switch is on, then the circuit is closed and electricity can flow through. If the switch if off, then the circuit is open and electricity does not flow through. http://www.youtube.com/watch?v=XnGiOe1WSbo http://www.youtube.com/watch?v=XnGiOe1WSbo

8. 4. Transformation of energy Some circuit components’ function is to transform electrical energy into another type of energy like sound, light or motion. http://www.youtube.com/watch?v=20Vb6hlLQSg http://www.youtube.com/watch?v=20Vb6hlLQSg