Energy efficient tube lights

Hello

A. T5 Fluorescent Lamps (Dia: 16mm / Base: G5)

B. T8 Fluorescent Lamps (Dia: 26mm / Base: G13)

C: T12 Fluorescent Lamps (Dia: 40.5mm / Base: G13)

Confused about Lamp Bases, look here: http://www.bltdirect.com/lampBaseExamples.php

D. Tri-Phosphorous (Triple)coatings are better than the earlier dual coatings used in fluorescent lamps.

Kind Regards....

In addition to Sparkstation's reply, the tubes were designed using English units. The T means it is tubular shape, the 5, 8, 12 are all telling you the outside diameter of the tube in eighths of an inch. Thus a T5 is 5/8" dia, with the approximate equivalent metric size(s) as noted by Sparkstation. This same convention was used in the other bulb sizes originating in the USA, with the letter(s) indicating the shape family the bulb or tube belongs to and the numbers the diameter in eighths of an inch. R = reflector, PAR = parabolic reflector (outdoor), BT = bulb-tubular, A = the traditional shape, F = flame shape, etc.

Fluorescent bulbs work with a low-pressure mercury vapor arc producing ultraviolet light which is absorbed by a thin coating of chemicals on the inside surface of the bulb. These chemicals have their electrons excited (moved to a higher shell for you chemists), and as they decay back to their ground state, they emit light of a particular color or wavelength range. These chemicals are called phosphors and their action is called fluorescence. By combining ones with different fluorescent colors you can make a tube which will fluoresce in a particular color, or more commonly in all the colors so it appears white. Vary the mix and the color will look a little more blue (selling diamonds), or a little more pink (at the meat counter), or anywhere in between or nearby.

Some phosphors are more expensive but also more efficient in their work. These are included in the "triple-phosphor" tubes. The additional cost buys a white which is more uniform across the color spectrum and is brighter for the same energy input.

The tubes are also designed for operation on ballasts with particular characteristics (the ballast provides the voltage needed to start and then maintain the arc and limits the arc current to a value which fits the tube's design). The action of the phosphors is more efficient as the applied arc frequency rises. Thus you can see more light output at the approx. 20,000 Hz of an electronic ballast than at the 50 or 60 Hz of a magnetic one. Put the better phosphors and electronic ballast together and you can get the same light output at up to 30% less energy input. Add a silver reflector and the usable light output is even higher. Put in a photocell to measure the ambient light and let it control the ballast's output to compensate for other sources of light (daylight from windows) and the savings go up and up!

Regards--John M.