Quote:
Originally Posted by Mr.Hachi.Roku
so the only way to tell a HID from a Halogen is from the colour temperature and brigtness? since both can be using projector lamps
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Wrong, HID's and Halogen's can have similar color temperatures and outputs although yes, most likely the rule of thumb is halogens are low color temperature and HID's are high, however it's not a perfect rule, it all depends on how each lamp is designed, you can achieve higher or lower color temperatures in each type by lengthening or shortening lamp life. For instance I've seen 5,000k halogen's (those little display lamps you see mounted to lighting tracks in stores are usually 5000k) and I've seen 2500k HID's (usually those orange street lamps you see on the highway.) Halogens however do require more power to output at the same brightness as HID's are they are only about 2% efficient at best where HID's are closer to 10 to 15%, florescent's are something like 40% efficient and LED's are 60%. Don't quote me on those numbers as I am trying to remember from memory...I don't have supporting documents in front of me.