TABLE OF CONTENTS A light source is any natural or artificial illumination. In fact, windows and skylights may be considered as dimmer-operated 'daylight fixtures' fitted with clear surface-mounted lenses. The electric potential a light source utilizes is usually 120 volts, rarely more than this, and occasionally 12 or 24 volts; and their wattages vary widely. Considering that a common incandescent lamp uses 120 volts and 100 watts, the current it consumes is less than one amp. Thus a dozen such lamps can be installed on one 15 amp circuit.
In this chapter, each artificial light source has a letter designation as follows:
| I | = | incandescent |
| Q | = | quartz, halogen, or tungsten-halogen |
| F | = | fluorescent |
| CF | = | compact fluorescent |
| MV | = | mercury vapor |
| MH | = | metal-halide |
| HPS | = | high-pressure sodium |
| LPS | = | low-pressure sodium |
| HID | = | high-density discharge (includes MV, MH, HPS, & LPS) |
| FO | = | fiber optic |
| LD | = | light-emitting or liquid-crystal display |
In the above light sources, usually only 4-8 percent of each lamp's life cycle costs is spent on its initial cost while 80-88 percent is spent on the energy consumed during its rated life (the rest goes toward installation and maintenance labor). In the eyes of many, such inefficient 'lumen lemons' are a major source of waste in our energy-extravagant society. Thus the federal government has outlawed several inefficient R, PAR, and fluorescent lamps, which industry has replaced with more efficient models such as compact fluorescent lamps.
Many industries today are conducting extensive research in new kinds...
