<a href=showthread.php?s=&postid=9936590#post9936590 target=_blank>Originally posted</a> by OrionN
You really missed the point. Have you ever take a measure of light intensity a foot or 18 inches from the 400W MH? H. magnifica does not need point source light, it just need the intensity of the MH, not the point source of MH.
GSMguy,
The technologies for NO, VHO, PC, T5 are the same. Sending a stream of high voltage electrons down a tube lined with various chemicals. Electrons repulse each other so they all travel along the inner of the glass tube where these chemical molecules are. The molecules absorbed the energy from these electrons then fluoresced to give off this energy as light.
The spectrum of the light depends on the chemical and the intensity depends on the amount of energy absorbed, and then gives off. This energy just depends on the current and the voltage of the electrons.
Did you know that for these lights, you can use the NO bulbs and put them in VHO ballast and it would work just fine, and will produce more light? That is because the VHO ballast produces more energy than the NO ballast, not because of the bulb.
I think there is constrains in how thin the glass is and how small one can make the tube. I think T5 is just small enough so that a larger numbers of tube with reflectors can fit under a limited space like our hood. That is why it is useful for us.
The technology of MH is somewhat the same, except the chemical involved is metal atoms which turn into ionized gas when bombarded with these electrons.
We were discussing the point source issue, not if 400 watt halides were more intense. However a cheesey 400 watt halide system might not put as much light in a tank as a good t5 system, it would really depend on a lot of variables, lamp height, brand, K rating, ballast, reflector.
VHO, NO, PC and T5 fluorescents use the same principle but there are differences in the gases used in each. I am not sure of the specific differences but T5's do have a higher resistance than the others and a lower mercury content. T5's do create more lumens per watt than the others.
Heres a good explaination of how Fluorescent lamps work.
When you turn the lamp on, the current flows through the electrical circuit to the electrodes. There is a considerable voltage across the electrodes, so electrons will migrate through the gas from one end of the tube to the other. This energy changes some of the mercury in the tube from a liquid to a gas. As electrons and charged atoms move through the tube, some of them will collide with the gaseous mercury atoms. These collisions excite the atoms, bumping electrons up to higher energy levels. When the electrons return to their original energy level, they release light photons. the wavelength of a photon is determined by the particular electron arrangement in the atom. The electrons in mercury atoms are arranged in such a way that they mostly release light photons in the ultraviolet wavelength range.
This is where the tube's phosphor powder coating comes in. Phosphors are substances that give off light when they are exposed to light. When a photon hits a phosphor atom, one of the phosphor's electrons jumps to a higher energy level and the atom heats up. When the electron falls back to its normal level, it releases energy in the form of another photon. This photon has less energy than the original photon, because some energy was lost as heat. In a fluorescent lamp, the emitted light is in the visible spectrum -- the phosphor gives off white light we can see. Manufacturers can vary the color of the light by using different combinations of phosphors.
Detailed article is here
http://www.howstuffworks.com/fluorescent-lamp.htm/printable
Now I really be done here. Yall have fun
