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===Meaning===
[[File:LightDependentResistorSymbol.png|right|300px|thumb|The symbol for a '''light dependent resistor'''.]]
A '''light dependent resistor''' ('''LDR''') is a [[resistor]] which changes [[Electrical Resistance|resistance]] depending on the intensity of [[light]] that it is exposed to.
===About Light Dependent Resistors===
: A '''light dependent resistor''' can be used to control the [[Potential Difference|potential difference]] of another [[Electrical Component|component]] in [[Series Circuit|series]] with it. If the [[light]] intensity on the '''light dependent resistor''' is decreased then the [[Potential Difference|potential difference]] across other [[Electrical Component|components]] will decrease.
: '''Light dependent resistors''' can be used in security [[light]]s and street lamps which activate depending on how dark it is.
{| class="wikitable"
|-
|[[File:LDRPotentialDivider1.png|center|300px]]
|[[File:LDRPotentialDivider2.png|center|300px]]
|-
| style="height:20px; width:200px; text-align:center;" |In this [[Circuit Diagram|circuit diagram]] the [[light]] intensity is low, which causes the [[Electrical Resistance|resistance]] of the '''LDR''' to be high. As a result the [[Potential Difference|potential difference]] across the [[electrical bulb|lamp]] will be high (5.9V) and the [[Electrical Current|current]] through the [[Electrical Bulb|lamp]] will be large. So in dim [[light]] the [[Electrical Bulb|lamp]] will remain unlit.
| style="height:20px; width:200px; text-align:center;" |In this [[Circuit Diagram|circuit diagram]] the [[light]] intensity is high, which causes the [[Electrical Resistance|resistance]] of the '''LDR''' to be low. As a [[result]] the [[Potential Difference|potential difference]] across the [[electrical bulb|lamp]] will be low (0.1V) and the [[Electrical Current|current]] through the [[Electrical Bulb|lamp]] will be low. So in bright [[light]] the [[Electrical Bulb|lamp]] will remain unlit.
|}