1. Light Dependent Resistor
(L.D.R.)
Circuit symbol
The resistance of the LDR changes as the
amount of light (intensity) falling on it
changes

2. Method to investigate how an LDR works
Measure the resistance of the LDR using an
Ohm meter when the light is blocked by layers of
plastic which is partly see through
2.Remove the layers of plastic one at a time so that
More light is reaching the LDR
3. Check what happens to the resistance of the LDR
as more light reaches it
More Light
Fill in the missing word
Resistance
in Ohms
the Resistance
Ohm metre
Light intensity

3. Thermistor Circuit symbol Increasing the temperature the Resistance
in Ohms
Circuit symbol
temperature
Increasing the temperature
the Resistance

4. Summary
As the light gets brighter the of the
As the temperature increases the
of the
resistance
LDR
resistance
thermistor

5. Answers
All the answers are DECEASES because the LDR and thermistor have an
Inverse relationship.
As the variable (light or temperature) increases
The resistance decreases

6. END