A light-dependent resistor (LDR), also called a photoresistor or photoconductive cell, is a passive semiconductor component whose resistance changes with light. In the usual behavior, more light means lower resistance. A circuit can use that change to detect whether an area is getting brighter or darker.
How does a light-dependent resistor work?
An LDR is photoconductive: when light is absorbed by its sensitive semiconductor, charge carriers become available to conduct electricity. As conductivity rises, resistance falls. The exact response depends on the specific component, so an LDR does not have one universal resistance curve or response speed.
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How does an LDR affect a circuit?
A common way to use an LDR is to pair it with a fixed resistor in a voltage divider. As illumination changes the LDR’s resistance, the voltage at the divider’s output changes too. The direction of that voltage change depends on whether the LDR is connected on the supply side or the ground side.
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#1 Best Overall
- 100pcs 5528 Light Dependent Resistor
Is an LDR the same as a photodiode or other light sensor?
No. An LDR changes resistance through photoconductivity. Photodiodes and photovoltaic cells use different mechanisms, while phototransistors use light to control transistor-like current. These components can all respond to light, but they are not interchangeable by definition; the right choice depends on the required response, circuit interface and sensing task. Analog Devices’ overview of light sensors distinguishes these sensor types.
Quick Recap
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- ☀ [What You Get]: What you will get is a 210pcs photoresistor kit. It includes 5mm photo light sensitive resistor GM5506 5516 5528 5537 5537-2 5539 5549, each for 30pcs. They are placed in a clean transparent box, and each type of photoresistor is placed separately and labeled to help you distinguish.
- ☀ [High Sensitivity]: The resistance value of the photoresistor decreases as the intensity of the incident light increases. Light-dependent resistors are made of cadmium sulfide have extremely high light sensitivity, and the response time of all models is less than or equal to 30ms.
- ☀ [Easy to Use]: The width of the photo light sensitive is 5mm, which is very small and can be installed in almost any related project. They can be used with Arduino to facilitate your measurement.
- ☀ [Good Reliability]: The resistor is coated with epoxy, which has good reliability and can serve you for a long time. It can work normally in an environment of -30 to 70 Celsius (-22 to 158 degree). It should be noted that please try to avoid direct sunlight.
- ☀ [Widely Application]: These resistors can be used for photoelectric control, camera automatic metering, children's electronic toys and circuit experiments. Many users use it as a substitute for solar lights, which can save you a lot of money.
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- High Sensitivity: The 5528 Light Dependent Resistor (LDR) features a high sensitivity to light, allowing it to accurately detect even the slightest changes in light intensity.
- Wide Range of Applications: This photoresistor is widely used in various electronic projects, such as light detection, automatic control, and light-sensitive alarms. It is compatible with Arduino and other microcontrollers, making it easy to integrate into your projects.
- Durable and Reliable: Made with high-quality materials, this LDR has a maximum voltage of 150 VDC and can withstand operating temperatures ranging from -30°C to +70°C. It also has a response time of 20ms (rise) and 30ms (down), ensuring quick and accurate light detection.
- Versatile Resistance Range: With a light resistance of 10-20 Kohm at 10 Lux and a dark resistance of 1 Mohm, this photoresistor offers a wide range of resistance values, allowing for precise control and measurement of light intensity.
- Explosive 5MM Photoresistor: This pack includes 100pcs of the 5528 Light Dependent Resistor, providing you with ample supply for your various projects. Whether you are a hobbyist or a professional, this bulk pack ensures that you always have enough photoresistors on hand.
Rank #3
- Maximum Voltage: 150 VDC
- Maximum Wattage: 100 mW
- Operating Temperature: - 30 ~ + 70 ℃
- Spectral Peak: 540 nm
- Light resistance (10 Lux): 50-100 KΩ
Rank #2
- Quantity: 30 x photoresistor, 5 mm GM5539 resistor
- Maximum voltage: 150 Volt DC
- Maximum wattage: 100 mW; Spectral peak: 540 nm
- Light resistance (10 Lux): 50-100 Kohm; Operating temperature: - 30 ~ + 70 degree Celsius
- Enough photo light sensitive resistors are handy for your DIY and hand working projects
What should you check before choosing an LDR?
- Model-specific specifications: Check the datasheet for the material, spectral response, resistance range and electrical limits. CdS (cadmium sulfide) photoresistors are one documented type, not a safe assumption for every LDR. Token Components describes a CdS photoresistor and its construction.
- Precision: Do not assume an unspecified LDR provides accurate lux readings. Component variation and the physical lighting setup matter; for a particular application, choose a specified part and calibrate it under the intended conditions. Adafruit’s photocell overview discusses practical variability and measurement limits.
- Required behavior: Compare the candidate sensor’s response and usable output range with the circuit and lighting conditions you need. There is no universal best light sensor for every application.
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