A preamble is usually used for formal documents; you wouldn't include one in a text to your best friend. noun-A preliminary statement, especially the introduction to a formal document that serves to explain its purpose. noun-An introductory occurrence or fact; a preliminary.
Screw-in types can be used in place of incandescents in standard lamp sockets. Available in a wide spectrum of colors. Warm white tones best duplicate the color of incandescents. Today's fluorescent bulbs come in a wide selection of sizes and can produce warm tones of light similar to those of incandescents.
Types of Light Sources and Light Bulbs. The performance of any light fixture depends very much on the light source (bulb) used. Different bulbs produce different lighting effects, and many bulbs have widely varying performance. To save energy, select the most efficient light bulb that will provide the type of lighting you need. Beginning in mid-2011, the packaging on your favorite light bulbs will change.