What does a photo cell typically react to in order to perform its function?

A photo cell, also known as a photodetector or light sensor, is specifically designed to respond to light levels in the environment. This type of sensor works by detecting the intensity of light and can automatically turn devices on or off depending on the ambient light conditions. For example, in outdoor lighting systems, a photo cell will activate the lights at dusk when light levels drop and deactivate them at dawn when light levels increase.

While temperature changes, movement detection, and sound signals are important features in other types of sensors, they are not relevant to the function of a photo cell. Temperature sensors monitor heat variations, motion sensors detect movement within a given area, and sound sensors respond to audio signals. These distinctions highlight why the primary function of a photo cell relies solely on light levels, making it a critical component in applications that require automatic lighting adjustments based on daylight availability.