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Electronic Components
Light Sensor (LDR)
The simplest way to give your projects the gift of sight. LDRs are essential for detecting day/night cycles and light motion.
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LDR (Light Dependent Resistor)
A photoresistor whose resistance decreases as the intensity of light increases. It is used to detect light levels in the environment.
Key Applications
- Automatic street lights
- Light intensity meters
- Shadow detectors
Resistance: 1MΩ (dark) to ~1kΩ (bright) | Passive component🧪The Science Behind It
An LDR works based on Photoconductivity. The sensor is made of a high-resistance semiconductor material like Cadmium Sulfide (CdS).
When photons (light particles) hit the sensor, they are absorbed and transfer energy to the electrons, allowing them to jump the "band gap" and flow as electricity. This effectively lowers the resistance of the component.Dark = High Resistance (MΩ)
Light = Low Resistance (kΩ)
Pin Configuration
Pin 1Positive or Analog Input (Non-polarized)
Pin 2Negative or Ground (Non-polarized)
NoteTypically used in a Voltage Divider circuit with a 10k resistor.