Wednesday, 6 May 2015

LDR vs light colour


Red, green, blue, IR and UV LEDs
4.5V power supply
Crocodile clip leads
Digital multimeter
Black cardboard tube


Connect an LED to the power supply and insert into one end of the tube so that it is the only light source.
Attach the LDR to the multimeter set to read Ohms and place in the other end of the tube.
Switch on the power supply and record the reading shown on the multimeter.
Repeat for each of the LED colours.

Ensure that the distance between the LED and LDR does not change and that the LED is the only light source able to affect the reading on the LDR.