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Light Dependent Resistor.
What is a Light Dependent Resistor?
A
light dependent
resistor (also called an LDR) is a
component
whose resistance changes when the
amount of light falling on it
changes. The amount of
light falling on a surface
is called the light intensity.
A light dependent resistor has its own circuit symbol.
As the amount of
light goes up the
resistance
goes down. As the resistance decreases,
the current
increases. In bright light a bigger
current will flow.
The curve in the plot
below shows that the
resistance decreases as the light intensity increases.
What is a Light Dependent Resistor used for?
The LDR can be used in a
circuit to automatically
switch lights on at night. See the uses
of a relay.
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