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Photoresistor Module

../_images/11_photoresistor_module.png

The photoresistor module is a device that can detect the intensity of light in the environment. It can be used for various purposes, such as adjusting the brightness of a device, detecting day and night, or activating a light switch.

An important component of the photoresistor module is the photoresistor. A photoresistor is a light-controlled variable resistor. The resistance of a photoresistor decreases with increasing incident light intensity; in other words, it exhibits photo conductivity.

A photoresistor can be applied in light-sensitive detector circuits and light-activated and dark-activated switching circuits acting as a resistance semiconductor. In the dark, a photoresistor can have a resistance as high as several megaohms (MΩ), while in the light, a photoresistor can have a resistance as low as a few hundred ohms.

Here is the electronic symbol of photoresistor.

../_images/11_photoresistor_symbol_2.png

Specification

  • Supply Voltage: 3.3V - 5V

  • PCB Size: 32 x 14mm

  • Output Signal Type: DO and AO

Pinout

  • VCC: This is the positive power supply input from the main control.

  • GND: Ground connection.

  • DO: Digital output. When the intensity of the light exceeds the threshold value (set by the potentiometer), D0 becomes LOW; otherwise, it remains HIGH.

  • AO: Analog output. The stronger the light, the lower the output value; conversely, the weaker the light, the higher the output value.

Principle

The photoresistor module works on the principle of changing resistance in response to different light intensities. The sensor has a built-in potentiometer that adjusts the sensor’s digital output (D0) threshold.

Schematic diagram

../_images/11_photoresistor_module_schematic.png

Example