Photoresistor Component Visualization

This is a simple p5.js visualization showing the characteristic structure of a photoresistor (Light Dependent Resistor).

View the Photoresistor Component

About Photoresistors

A photoresistor is a light-sensitive component whose electrical resistance decreases with increasing incident light intensity.

Key Features:

• Serpentine Pattern: The distinctive zigzag pattern you see is the light-sensitive material. This pattern maximizes the surface area exposed to light within a compact space.
• Variable Resistance:
• In darkness: ~1MΩ (1,000,000 ohms) or higher
• In bright light: ~50-100Ω
• Common Uses: Nightlights, street lamps, camera light meters, alarm systems

How It Works

The serpentine pattern is made of a semiconductor material (often cadmium sulfide). When light photons hit this material, they excite electrons, making it easier for current to flow, which decreases the resistance.

Circuit Applications

Photoresistors are typically used in a voltage divider circuit paired with a fixed resistor. As light levels change, the voltage at the midpoint of the divider changes, which can be read by a microcontroller or used to control other components like transistors.

See the LED Nightlight Circuit for an example of a photoresistor in action.