These small 10mm LDR (Light Dependent Resistor) are also called a photoresistor. An LDR is a resistor whose resistance changes with the amount of light striking it.
Key Features of Light Depentent Resistor:
As the strength of the light falling on the LDR increases, the resistance of the LDR gets lower.
It is typical to put the LDR in series with a resistor to create a voltage divider and feed that output to an analog input on an MCU. The output will be a lower voltage when no light is striking the sensor and the voltage will increase as the light intensity increases.
These can be used in a variety of applications such as monitoring a pilot light, night light control or anywhere that you want to detect a basic threshold of light and take some action.
| LDR Resistance Value | Light Intensity |
| 20K | Sensor blocked |
| 17K | Very dim room |
| 3K | Moderate room light |
| 950 | Overcast daylight |
| 400 | Next to fluorescent bulb |
Size: 10mmx 2 (D x No. of Pins)
Technical Specifications
| Operating Ratings | Max Voltage | 250V |
| Max Power Dissipation | 200mW | |
| Peak Detection Wavelength | 540nm (similar to human eye) | |
| Dimensions | Sensor Diameter | 10mm |
