Don's bulbs rare light bulbs and lamps glossary of terms definition of: BROAD SPECTRUM What is BROAD SPECTRUM? BROAD SPECTRUM refers to FULL SPECTRUM. Broad Spectrum light source capable of producing colors thought the entire range of the visible spectrum; simulating actual sunlight. High CRI output with Kelvin temperatures ranging between 5500K and 5900K. references for this page: FULL SPECTRUM, BROAD SPECTRUM reference to this page: NEODYMIUM