DESCRIPTION

LDR (Light Dependent Resistor) is a resistor whose resistance varies inversely with the amount of light falling on it. It is also known as photo resistor, photocell, photo conductive cell etc. LDR are available in 5mm,12mm and 20mm dimensions.LDR (Light Dependent Resistor) available at Tomson Electronics, Kochi, Kerala, India is the best quality product

LDR is made of high resistance semiconductor material. Semiconductor material used for the photo resistors is cadmium sulphide, CdS. When its dark, LDR has high resistance known as dark resistance. Usually dark resistance will be in the range of mega ohms. When light falls on LDR, resistance reduce to kilo ohms range.

Working principle: when light falls on LDR i.e. when photons fall on LDR, valence band electrons get sufficient energy to get excited to the conduction band. Incident photons must have energy greater than the forbidden energy gap of the semiconductor. When light having enough energy falls on the device, more electrons will get excited to conduction band. As the number of free electrons increases, more current flows through the circuit. Hence it is said that, as light falls on LDR, resistance decreases.

FEATURES

• Coated with epoxy
• Good reliability
• Small volume
• High sensitivity
• Fast response
• Good spectrum characteristic

DEVELOPMENT SOURCES

Datasheet

APPLICATIONS

• Burglar Alarms
• Light Detectors
• Light Sensor
• Color Sensor
• Line Sensor
• OBJECT SENSOR
• Photo Switch
• Lighting Controls For Street Lamps
• Light Intensity Meters

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5mm – LDR (Light Dependent Resistor)