Photoresistor

LDR 1480405 6 7 HDR Enhancer 1

Light-sensitive resistor

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A photoresistor, also known as a light-dependent resistor (LDR), is a passive electronic component whose resistance decreases with increasing incident light intensity. It is a type of resistor whose resistance varies significantly with the amount of light falling on its surface.

Working Principle

The working principle of a photoresistor is based on photoconductivity, which is an optical phenomenon in which the material's conductivity is increased when it absorbs electromagnetic radiation, such as visible light. When light falls on the photoresistor, the number of charge carriers increases, leading to a decrease in resistance.

Materials

Photoresistors are typically made from semiconductor materials such as cadmium sulfide (CdS) or cadmium selenide (CdSe). These materials have properties that make them sensitive to light, allowing them to change their resistance based on the intensity of the light.

Applications

Photoresistors are used in various applications, including:

• Light meters
• Street lights
• Clocks
• Alarm systems
• Cameras
• Solar garden lights

Advantages and Disadvantages

Advantages

• Simple and inexpensive
• Easy to use in analog circuits
• Wide range of resistance values

Disadvantages

• Slow response time compared to other light sensors
• Sensitivity to temperature changes
• Limited spectral response

Related Components

• Photodiode
• Phototransistor
• Photovoltaic cell

See Also

• Resistor
• Semiconductor
• Photoconductivity
• Light sensor

Related Pages

• Resistor
• Photodiode
• Phototransistor
• Photovoltaic cell
• Semiconductor
• Light sensor

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