1. Review Read the comments I have written in your book.
Complete your next steps in PURPLE PEN.
Correct any Spelling and Grammar mistakes in PURPLE PEN.

2. Engage
On your whiteboard, explain what current, voltage and resistance are.
Use a diagram to support your explanation.

3. Investigating Resistance
All core practical's should be completed in the back of your exercise books
01/12/2018
c/w
CORE PRACTICAL 5
Investigating Resistance
P2.6

4. Specification Points

5. Investigate the relationship between Current and Voltage for a fixed resistor
Connect up the circuit as shown
Increase the voltage on the power pack 2V at a time.
Record the current and voltage in a table.
Calculate the resistance by doing R = V/I
Voltage (V)
Current (A)
Resistance 2 4 6 8 10 12

6. Plot a graph of your results
Explain
Plot a graph of your results
current
Go up in 0.01s or 0.02s
voltage
Go up in 2s

7. Current-Voltage graph for a fixed resistor
Explain
Current-Voltage graph for a fixed resistor
Voltage (V)
Current (A) 2
0.02 4
0.04 6
0.06 8
0.08 10
0.10 12
0.12

8. The current-voltage graph for a fixed resistor is a straight line, showing the resistance stays the same
The steepness of the graph tells us about the resistance:
Steeper = low resistance Flatter = high resistance
Key Notes

9. Investigate the relationship between Current and Voltage for a lamp
Connect up the circuit as shown
Increase the voltage on the power pack 2V at a time.
Record the current and voltage in a table.
Calculate the resistance by doing R = V/I
Voltage (V)
Current (A)
Resistance 2 4 6 8 10 12

10. Key Notes For a light bulb the graph gets flatter with more voltage.
This means there is more
resistance.
This happens because the
bulb gets hotter.
Key Notes

11. Key Notes A diode only lets current flow in one direction.
It has a very high resistance in the other direction, which stops the current flowing.
For a light bulb the graph gets flatter with more voltage.
This means there is more
resistance.
This happens because the
bulb gets hotter.
Key Notes

12. Extend Describe each of these graphs…
What happens to the steepness (resistance)?

13. In your own words explain the use of
Extend
In your own words explain the use of
LDRs and Thermistors
What affects there resistance?
How does their resistance change (what shape graph)?
How might they be used to control other components in a circuit?

14. Key Notes LIGHT DEPENDENT RESISTORS
The resistance decreases as the light intensity increases.
THERMISTOR
The resistance decreases as the temperature increases.
Remember, the resistance will affect how much current flows in the rest of the circuit
Key Notes