LDR Sensor (Light Dependent Resistor) - 5mm

5mm LDR (Light Dependent Resistor) Photocell Sensor

The 5mm LDR (Light Dependent Resistor), also known as a photocell or photoresistor, is a simple, low-cost sensor for detecting the presence and intensity of ambient light. This two-terminal component's resistance changes dynamically with the amount of light it's exposed to: in the dark, its resistance is very high (in the megaohms); in bright light, its resistance drops significantly (to a few kilohms). This simple principle makes it the "eye" for countless electronics projects, from automatic night lights to line-following robots.

🔧 Key Features

• Simple Light Sensing: An easy-to-use, two-pin analog sensor for all types of light detection.
• High Dynamic Range: Resistance varies dramatically from >1MΩ (dark) to <20kΩ (light), providing a clear signal for a microcontroller.
• Spectral Response: The Cadmium-Sulfide (CdS) cell has a spectral response similar to that of the human eye.
• Standard 5mm Package: The 5mm diameter makes it easy to mount in enclosures, panels, or directly on a breadboard.
• Passive Component: Requires no special power supply, just a simple voltage divider circuit to be read by an analog pin.

💡 Applications

• Automatic Night Lights: Automatically turn on a light when the room gets dark.
• Line-Following Robots: Used in pairs to detect a black line on a white surface (or vice versa).
• Dark-Activated Alarms: Trigger an alarm or event when a light source is interrupted (like a "laser" tripwire).
* Light Meters: Create a simple device to measure ambient light levels.
• Camera Exposure Control: Used in simple cameras to determine the correct shutter speed.

⚙️ Technical Specifications

📦 Package Includes

• 1 × 5mm LDR Sensor

✅ Why Choose This Sensor?

• Extremely Low Cost: The most affordable way to add light sensing to your project.
• Incredibly Simple: Requires only one other resistor to create a voltage divider that can be read by any ADC pin on a microcontroller.
• Versatile and Reliable: A time-tested component that is perfect for beginners and advanced projects alike.
• No Complex Code Needed: Reading the sensor is as simple as a single `analogRead()` command on an Arduino.