1. Learning Objective
To be able to:
Describe the role and function of diodes and filament bulbs
Key Words:
Current, potential difference, resistance

2. Components adding resistance
Wednesday, 22 May 2019
Components adding resistance
Date and title in books. You need a pen, pencil & ruler.
Starter Activity – 5 minutes
Exam question

3. Describe the uses for filament bulbs and diodes
Target 9-1
Describe the role of a filament bulb and a diode within a circuit
(F/H)
Target 4-9
Draw a graph to show the p.d. and current for a filament bulb and a diode
(H)
Target 5-9
Describe the uses for filament bulbs and diodes
Extension: Application of Knowledge
Target 8/9
Explain the graphs of a filament bulb and diode, in terms of resistance
Learning Outcomes

4. Filament Lamps This is a normal, filament lamp bulb.
What happens to the current as we increase the p.d?
We are going to investigate!

5. Table of Results We need to design a table of results
What are we controlling, measuring and changing?
How do we design a table based on this?
What values for p.d should we use? (THINK!)

6. Potential Difference (V)
Table of Results
Potential Difference (V)
Current (A) 4 5 6 7 8 9 10 11 12

7. Graph! Now draw a graph of your results.
In Physics we NEVER join the points. We draw lines or curves of best fit. 
What shape do you have?
What do you think this is telling us?

8. Filament Bulb A bulb heats up as we use it. The resistance increases
The graph is no longer a straight line!

10. Diode The diode has a very high resistance in one direction.
This means that current can only flow in the other direction