1. Current/ Potential Difference

2. Electrons Flow
- + e-
Electrons are negatively charged and therefore flow from negative to positive

3. Current We use an ammeter to measure current
Current is the FLOW OF ELECTRONS AROUND A CIRCUIT
In metals, current is carried by electrons
We use an ammeter to measure current
The unit of current is the ampere (A)

4. Current in a Series Circuit
The Current in a Series Circuit is the Same at Every Point

5. In a series circuit the bulbs are all the same brightness
If the bulbs are of the same rating!

6. Current Questions A B C
The current reading for bulb B is 2A. What are the readings for bulbs A and C?
Bulb B suddenly fails. What happens to bulbs A and C?

7. What Is the Current at This Point?

8. Brightness of Bulbs in a Series Circuit
If a cell is added the current will increase and the bulb gets brighter

9. Brightness of Bulbs in a Series Circuit
If a bulb is added the current will decrease as there is greater resistance in the circuit and the bulbs get dimmer

10. Current in a Parallel Circuit
A PARALLEL circuit has more than one path for the current to flow through
Assuming both bulbs are the Same…they will be the same brightness
Bulb A
Bulb B

11. Current in a Parallel Circuit
The Advantages of a parallel circuit are:
If one bulb fails ….the other will remain on
Both bulbs can be switched on separately
Bulb A
Bulb B

12. Current in a Parallel Circuit
The total flow of current is equal to the total current from all of the branches 2A 2A 2A

13. What is the ammeter reading?

14. Voltage (Potential Difference)

15. Voltage Is the Driving Force That Pushes the Current Around the Circuit

16. Potential Difference/ Voltage
This is VOLTA. He studied the driving force that pushes current around a circuit. He gave his name to the unit of Potential Difference
The unit of Potential Difference is the VOLT (V)

17. Voltage in a Series Circuit
The voltage in a series circuit is shared across each component. The sum of the voltages across each component equals the source voltage
12V 4V 4V 4V
12V

18. What Is the Voltage? ?V 8V 8V 8V ?V

19. Voltage in a Parallel Circuit
The voltage is the same across all components in parallel 6V

20. What Is the Voltage? 9V
? V
? V
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21. Complete the meter readings
12V A2 A3 V1 A1 V2 V3

22. Which Is the Series and Parallel Circuit
A * Current is THE SAME at any point
* Voltage SPLITS UP over each component B
* Current SPLITS UP down each branch
* Voltage is THE SAME across each branch

23. Summary Table Current Voltage Resistance
Is the flow of electrons around a circuit
Voltage
Is the driving force that pushes the current around.
Resistance
Is anything in a circuit which slows the flow down