1. Current Electricity and Electric Circuits

2. Static vs. Current Electricity
Static Electricity: charges build up in one location
Current Electricity: electrons on the move

3. Current Electricity
To operate electrical devices, you need a steady flow of electrons.
Current electricity is the continuous flow of electrons in a circuit.
The electrons flow continuously if the following conditions are met:
there is a continual supply of energy
the electrons have a a complete path to flow through (electric circuit)

4. Electric Circuits An electric circuit must include:
An energy source – “energizes” the electrons, ex. battery
a conducting wire (connector) – provides a path for current to flow
A load – converts electrical energy to another form of energy, ex. light bulb
Many electric circuits also include a switch that turns the circuit on or off by closing or opening the circuit.

5. Examples of Loads Examples of Loads Converts electricity to…
light bulb
light energy
fan
mechanical energy
doorbell
sound energy

6. Schematic Circuit Diagrams
special symbols that show the components and connections in a circuit.
a drawing made with these symbols is called a circuit diagram.

7. Schematic Circuit Diagrams
Follow these rules when you draw circuit diagrams.
1. Always use a ruler to draw straight lines for the conducting wires.
2. Make right-angle corners so that your finished diagram is a rectangle.

8. Circuit Symbols Conductor or wire
allows current to flow very easily from one part of a circuit to another.

9. Circuit Symbols
Cell - supplies electrical energy

10. Circuit Symbols
Battery: a combination of two or more cells

11. Circuit Symbols
Ground
a connection to earth

12. Circuit Symbols
Switch - an on-off switch allows current to flow only when it is in the closed (on) position

13. Circuit Symbols Light Bulb
a load which converts electrical energy to light

14. Circuit Symbols
Resistor
A resistor restricts the flow of current

15. Circuit Symbols
Ammeter
device that measures current A

16. Circuit Symbols
Voltmeter
device that measures voltage V

17. Circuit Symbols
Motor -electrical load that converts electrical energy into movement M

18. Circuit Building
Draw the circuit diagrams for each circuit described on the handout