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LDR Sensor

Light dependent resistor(LDR) is a resistor whose resistance varies with variation in light intensity. It is a low cost photo sensitive element. LDR uses a photconductor between two contacts. Normally the resistance of LDR is very high, when shed by light its resistance varies. When it is exposed to light a resistance decreases.There are various application of LDR viz, in line follower robot,night security etc, light control of street lamps, etc.


Size: Round, 5mm (0.2") diameter.
Resistance range: 200KOhms (dark) to 10KOhms (10 lux brightness)
Sensitivity range: CdS cells respond to light between 400nm (violet) and 600nm (orange) wavelengths, peaking at about 520nm (green).
Power supply: pretty much anything up to 100V, uses less than 1mA of current on average (depends on power supply voltage)


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Circuit Diagram



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