1. Physics 3: Electricity and Magnetism
Circuit Notes
Physics 3:
Electricity and Magnetism

2. Circuits Closed loop made up of at least two electrical elements
Consists of at least a power source, wire, and a device that uses electrical energy (like a light bulb)
Current travels from the negative side of the battery to the positive side

3. Symbols for Circuit Diagrams
Positive Side of Power Source
Wire
Power Source
Bulb
Resistance
Switch (open) (closed)
Negative Side of Power Source

4. Open Circuit
Light will not go on because the wire IS NOT CONNECTED to the battery on both sides; current will NOT flow

5. Closed Circuit
Light bulb turns on because the electrical current CAN now flow through the complete circuit

6. Series Circuit
All parts of the circuit are connected one after another in a loop
There is only one path for the electrons to follow
If one part goes out
The circuit goes from closed to open
Electricity will not flow
All parts go out
The voltage is split through each part of the circuit
The current is the same throughout the circuit
Example: Christmas Tree Lights

7. Series Circuit Examples
A complete circuit turns the light bulbs on

8. Series Circuit Examples
This Light Bulb is Burnt Out
The burnt bulb stops the electron flow to the rest of the circuit

9. Parallel Circuit
There is more than one path or branch for the electrons
If a break occurs in one branch, the electrons can still flow in the other
The voltage is the same throughout each branch
The current is split through each branch
Example: Household Wiring

10. Parallel Circuit ExamplesB A
PATH #1
PATH #2
Current divides and has more than one path

11. Parallel Circuit Examples
This Light Bulb is Burnt Out A B
Even though Bulb “B” is burnt out, the current still goes through the other circuit and Bulb “A” remains lit

12. Circuit Breakers Circuit breakers control the amount of current
If there are too many appliances running at one time, the circuit breaker opens the circuit to prevent a fire from occurring
You just have to flip the switch to get the appliances running again
Where is your circuit breaker in your house?

13. Fuses Fuses melt when the current is too great
Fuses need to be replaced in order to work again
Example: fuse in your car