Lighting Basics

California and other states have ended sales of fluorescent tubes and pin-base CFLs. What's banned, what's still legal to use, and the LED replacement for each lamp type, including how to choose Type A or Type B tubes.

Match a replacement fluorescent ballast from the old label: lamp type, number of lamps, voltage, starting method and ballast factor. Plus how to tell a bad ballast from a bad lamp, and when a Type B LED tube is the better buy.

Constant current or constant voltage, Class 1 or Class 2, wattage headroom and dimming: what to copy from the old driver's label so the replacement doesn't burn out your LEDs.

How does a Fluorescent lamp work? Fluorescent lamps are “gaseous discharge” light sources. Light is produced by passing an electric arc between tungsten cathodes in a tube filled with a low pressure mercury vapor and other gases. The arc excites the mercury vapor which generates radiant energy, primarily in the ultraviolet range. Fluorescent light bulbs use mercury to create the white light that we see. While mercury is a very effective light bulb material, it is also incredibly toxic and can cause mercury poisoning if the bulb breaks. In order to learn more about this issue and what you can...

In order to understand the technology that allows each lamp type to produce light, it is important to review certain basic principles. This post covers lumens, service life, foot-candles, lighting source types, beam angle and other foundations of lighting.

What is Light?  Light travels at 186,000 miles per second and is expressed in wavelengths in billionths of a meter (nanometers). This visually perceived energy is measured in the range of wavelengths from 380 nm to 780 nm, a small portion of the electromagnetic spectrum  The color temperature of the lamp and the quality of color rendering (Color Rendering Index) of different lighting sources will impact your perception of colors, as the different wavelengths are reflected off objects.   How the Eyes Work  Light from a source (sun, lamp, etc.) is reflected off an object, first entering the eyes through the...