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View Full Version : Sulfur lamps, and technology behind lighting



khronik
06-25-2007, 05:25 PM
Having one of these lamps would be like owning a mini sun. These things are brighter than just about any light source that's ever been made. However, they are new technology and are not available yet commercially.

There are two ways that electric light can be produced, ionization and black-body radiation. Black-body radiation is how incandescent lights work, and is how our sun works. If something gets really hot, it will give off electromagnetic radiation, first at long invisible wavelengths like infrared, and then, if it gets hot enough, at shorter visible wavelengths. First it would glow red, then yellow, then white, as more wavelengths are added. However, these light sources necessarily give off lots and lots of heat, so they're not much good for growing.

Ionization is much better at giving off only specific wavelengths of light. This is like the light that you see from an electric spark. A gas is typically ionized by running an electric current through it. Once the gas is ionized, it conducts electricity REALLY well, so the ballast has to shut off the current going through it so there's no short circuit. Once this happens, the gas reverts back to its original state, and gives off light. This constant ionization and discharge is how fluorescent and HID lighting works, and it is the reason why there is a flicker and a hum to these lights.

Most HID lights used for growing plants work by combining a bunch of different chemicals in a tube. Each chemical gives off a few different wavelengths when it discharges, and by combining several chemicals, the color of the light can be changed. However, when selecting the chemicals they have to make sure that the chemicals don't corrode the electrodes that are used to run current through the mixture. This limits their choices to mostly metals, halides, and noble gases.

However, there are other chemicals, like sulfur, that have much better spectrums than those currently in use. Unfortunately sulfur is about as corrosive as they come, and would make short work of any electrodes used to run current through it. They can get around this by putting the sulfur inside a quartz sphere and ionizing it by bombarding it with microwave radiation instead. Since just about nothing corrodes quartz, this works great. The only problem is, you need a huge magnetron, like the ones used in microwave ovens, to ionize the sulfur, not just a little ballast. This creates a few problems. First, small sulfur lights are very impractical because of the energy necessary to run the magnetron. Second, these magnetrons produce a lot of radio interference on the same wavelengths as cordless phones and cell phones. If these ever caught on among growers, cops would be able to detect them from the other side of a city with the right equipment. And of course, the neighbors could complain that their cordless phones weren't working, and some authorities might start looking into it.

Hope this helps! :smokin: