Navigation Light Rules |
Recreational boats operating at night are required to display navigation lights between sunset and sunrise. Recent changes to the Inland Navigation Rules make them nearly identical to the International Rules, so we will describe the International Rules to simplify the choices.
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Light Emitting Diodes, more commonly known as LEDs, operate at lower temperatures, use less energy, tolerate vibration better and last far longer than conventional incandescent bulbs. They also do not contain small amounts of toxic mercury, an environmental disposal hazard associated with fluorescent and compact fluorescent lamp (CFL) lights. LEDs cost a bit more, but are worth their premium price in the long run. Here’s why:
The light bulb, that marvel of technology created by Thomas Edison, operates by cramming a large volume of electrical current through a resistor encapsulated in a vacuum. This resistor, the tungsten filament, gets so hot that it glows white, and only the absence of oxygen prevents it from burning up in an instant. About 5% of the energy is released as light. The rest is mostly turned into heat, as we all know from burning our fingertips when we try to change a 60-watt bulb.
After more than a century, we’re still depending on Edison’s technology, but there are now cooler, more energy-efficient, and more “elegant” alternatives. In the very near future we’ll be seeing a lot more of them, mainly because they will reduce energy use and the production of greenhouse gasses. The Energy Independence and Security Act of 2007 requires roughly 25 percent greater efficiency for light bulbs, phased in from 2012 through 2014, beginning with the 100W bulb. This will effectively ban the sale of most current incandescent light bulbs. As of January 1st, 2011, standard 100W incandescent light bulbs have already been phased out of California stores. By 2020, bulbs must be 70 percent more efficient than they are today.
LEDs are diodes, semiconductors that allow current to flow in only one direction. Two materials are placed very close together in what is called a “P-N junction”. Run a current through the junction, and light energy is released
LEDs’ light color emission is determined by the chemistry of the device. There are two primary varieties of LEDs. The first, blue, white, green and ultraviolet LEDs use indium gallium nitride (InGaN).