1. ELECTRICITY & ELECTRONICS
INT 2 PHYSICS
ELECTRICITY & ELECTRONICS

2. LOCKERBIE ACADEMY PHYSICS DEPT
Ways to work out voltage divider circuits.
Follow the plan below:

3. LOCKERBIE ACADEMY PHYSICS DEPT
1. Identify the component
2. Set the conditions
3. Decide what happens to the resistance
Work out the effect of the voltage across the component
5. Find the effect on Vout

4. LOCKERBIE ACADEMY PHYSICS DEPTV Vs 0V

5. V Vs 0V
1. Identify the component
LDR

6. V Vs 0V
2. Set the conditions
As light increases

7. As light increases RESISTANCE decreasesV Vs 0V
3. Decide what happens to the resistance
As light increases RESISTANCE decreases

8. As resistance decreases voltage across the LDR decreasesVs 0V
Work out the effect of the voltage across the component
As resistance decreases voltage across the LDR decreases

9. As VLDR decreases Vout increases as they are not the sameVs 0V
5. Find the effect on Vout
As VLDR decreases Vout increases as they are not the same

10. 1. Identify the componentV Vs 0V
1. Identify the component
2. Set the conditions
3. Decide what happens to the resistance
Work out the effect of the voltage across the component
5. Find the effect on Vout

11. As light increases RESISTANCE decreases
How this circuit works
LDR V Vs 0V
As light increases
RESISTANCE decreases
Voltage across the LDR decreases
As VLDR decrease Vout increases as they are not the same
SUMMARY: As light increases Vout increases
USE: Greenhouse sprinkler system
Heating to come on during the day

12. Now try this one yourselfVs 0V V t

13. LOCKERBIE ACADEMY PHYSICS DEPT
Thank you for your patience