Everlight Electronics ALS-PT204-6C/L177 3mm Plugin Ambient Light Sensor ROHS

The Everlight Electronics ALS-PT204-6C/L177 operates from 2.5V to 5.5V DC, making it compatible with both 3.3V and 5V microcontroller systems like Arduino, Raspberry Pi, and ESP32. This wide range provides flexibility in various electronic designs without requiring additional voltage regulation.

This sensor incorporates an integrated infrared rejection filter over its silicon photodiode. This filter attenuates infrared wavelengths, ensuring the spectral response closely matches the human eye's photopic sensitivity curve (peak around 550nm). This results in more accurate measurements of perceived visible light, crucial for automatic display brightness adjustment.

The sensor has two pins: cathode and anode. It functions as a photodiode, generating a current proportional to light intensity. For reading, connect it in reverse bias with a series resistor to create a voltage divider. Measure the voltage drop across the resistor using a microcontroller's ADC pin. The higher the light intensity, the greater the photocurrent and the lower the output voltage.

Its primary application is automatic display brightness control in consumer electronics (phones, tablets, laptops) and automotive dashboards. By accurately measuring ambient light levels that match human perception, it enables systems to dynamically adjust screen brightness, optimizing visibility while conserving battery power. It's also used in smart lighting and IoT devices.