CMH Ceramic Metal Halide
A CMH (Ceramic Metal Halide) lamp is simply a new generation of MH (Metal Halide) lamp. The major technical evolution between the two models of bulbs is that the CMH is equipped with a ceramic composite tube while a traditional MH uses quartz.
This new evolution uses a ceramic tube that tolerates much higher temperatures than metal tubes. HID lamps use a quartz tube that requires the use of a gas mixture that lowers the core temperature of the tube, but does not provide an ideal light spectrum for plant growth.
In contrast, CMH lamps use a ceramic tube whose ability to operate at high temperatures allows for an ideal gas combination and therefore an optimal light spectrum.
The Thorn group was the creator of this technology in 1981, but it was the Phillips company that, from 1994, was the first international distributor.
It is necessary to use a specific magnetic or digital ballast, because CMH lamps work only with digital ballasts emitting low frequencies and not high frequencies.
There are generally 2 different models of CMH lamps, the 3100 K (full spectrum) and the 4200 K (blue spectrum). CMH lamps are currently used to illuminate commercial areas, the streets of various cities, as well as many horticultural operations.
