What type of detector features a light-sensitive unit?

The type of detector that features a light-sensitive unit is the flame detector. A flame detector works by detecting the light emitted from a flame, often in the ultraviolet or infrared spectrum. These detectors can identify the presence of a flame based on the specific wavelengths of light that are characteristic of combustion processes. Because flames emit radiant energy, light-sensitive units within these detectors are specifically designed to respond to these wavelengths, enabling them to alert operators to the presence of fire quickly.

Other types of detectors, such as smoke detectors, thermal detectors, and gas detectors, rely on different principles. Smoke detectors typically sense particles in the air caused by smoke, thermal detectors respond to heat changes, and gas detectors identify the presence of specific gases through chemical or electrical sensing methods. Each of these types operates based on different principles, separating them from the operation of flame detectors.