Analog Solar Radiation Sensors

Direct sunlight has a luminous efficacy of about 93 lumens per watt of radiant flux, which includes infrared, visible, and ultra-violet light. Bright sunlight provides luminance of approximately 100,000 candela per square meter at the Earth's surface. This can be divided into five regions in increasing order of wavelengths; Ultraviolet C, Ultraviolet B, Ultraviolet A, Visible Range and Infrared.