LIGHT DEPENDENT RESISTOR
AIM- To study L.D.R characteristics.
APPARATUS - L.D.R, Bulb, variable transformer (0 to 300V).
THEORY - The L.D.R is light dependent resistor. It consist of the material like Cadmium Sulphide, Cadmium Selenide. Most commonly Cadmium Sulphide is used. These material when exposed to light their conductivity increases that is resistivity decreases. In other words L.D.R will have very high dark resistance. The material used here is photo sensitive. L.D.R is used in Light meter, Photo Relay, Burglar alarm etc.
PROCEDURE-
OBSERVATION TABLE –
Sr.No Applied voltage (to the bulb) Resistance of LDR
CONCLUSION –
When the applied voltage is increased the light intensity of the lamp increases , which in turn reduces the resistance value of L.D.R.
APPARATUS - L.D.R, Bulb, variable transformer (0 to 300V).
THEORY - The L.D.R is light dependent resistor. It consist of the material like Cadmium Sulphide, Cadmium Selenide. Most commonly Cadmium Sulphide is used. These material when exposed to light their conductivity increases that is resistivity decreases. In other words L.D.R will have very high dark resistance. The material used here is photo sensitive. L.D.R is used in Light meter, Photo Relay, Burglar alarm etc.
PROCEDURE-
- Keep the L.D.R and bulb in the dark box.
- Connect L.D.R to Ohm meter
- Increase the voltage applied to the bulb which increases the intensity of the bulb
- Measure resistance of L.D.R for every step of rise in applied voltage.
- Draw the graph of voltage verses resistance.
OBSERVATION TABLE –
Sr.No Applied voltage (to the bulb) Resistance of LDR
CONCLUSION –
When the applied voltage is increased the light intensity of the lamp increases , which in turn reduces the resistance value of L.D.R.