Christmas lights: Encyclopedia - Christmas lights

Christmas lights

Christmas lights (also sometimes called fairy lights or twinkle lights) are strands of electric lights used to decorate homes and Christmas trees during the holiday season, mostly in the West. Christmas lights come in a dazzling array of configurations and colors.

Christmas lights - History

The first known electrically-illuminated Christmas tree was the creation of Edward H. Johnson, an associate of inventor Thomas Edison. While he was vice president of the Edison Electric Light Company, a predecessor of today's Con Edison electric utility, he had Christmas tree light bulbs especially made for him. He proudly displayed his Christmas tree, which was hand-wired with 80 red, white and blue electric incandescent light bulbs the size of walnuts, on December 22, 1882 at his home on Fifth Avenue in New York City. Local newpapers ignored the story, seeing it as a publicity stunt. However, it was published by a Detroit newspaper reporter, and Johnson became the Father of Electric Christmas Tree Lights.

From that point on, electrically illuminated Christmas trees, indoors and outdoors, grew with mounting enthusiasm in the United States and elsewhere. In 1895, U.S. President Grover Cleveland proudly sponsored the first electrically lit Christmas tree in the White House. It was a huge specimen, featuring more than a hundred multicolored lights. The first commercially produced Christmas tree lamps were manufactured in strings of multiples of eight sockets by the General Electric Co. of Harrison, New Jersey. Each socket took a miniature two-candlepower carbon-filament lamp.

Over a period of time, strings of Christmas lights found their way into use in places other than just Christmas trees. Soon, strings of lights adorned mantles and doorways inside homes, and ran along the rafters, roof lines, and porch railings of homes and businesses. In recent times, many city skyscrapers are decorated with long mostly-vertical strings of a common theme, and are activiated simultaneously in Grand Illumination ceremonies.

Christmas lights - Types

In modern times, Christmas lighting devices can be based on different technologies. Common technologies are incandescent light bulbs and now LEDs. Lightbulbs or LEDs are usually connected in series to be powered from mains without a transformer (LED-based strings, of course, have a current-limiting resistor). Neon lamp based strings have lamps connected in parallel, each with its own current-limiting resistor. All battery-powered lights are wired in parallel.

Other setups include lightbulb or LED-based strings with a line isolation step down transformer with bulbs or LEDs connected in parallel (LEDs have current limiting resistors). These sets are much safer, but there is a voltage drop at the end of the string (less noticeable with LED than incandescent). There is also the "wall wart" transformer which may be difficult to plug in certain places.

There are even Christmas light sets that use fiber optic technology. They are usually incorporated into an artificial Christmas tree. They have light bulbs or LEDs in the tree base and many fiber optic wires going to the leaves of the tree. These devices always have line isolation step-down transformer, because they have only one or two bulbs or LEDs.

Christmas lights can be animated. This is done by using special flasher or "interrupter bulbs" or electronically. An electronic Christmas light controller usually has a diode bridge followed by a resistor-based voltage divider, a filter capacitor and a fixed-program microcontroller. The animation modes are changed by pressing a button. The microcontroller has three or four outputs which are connected to transistors or thyristors. They control interleaved strings: commonly red, green, blue and yellow, or other combinations such as red, green and white.

Fiber-optic Christmas trees can also be animated electronically, but more often this is done by means of a rotating color filter disc.

Christmas lights - Safety

In the past, Christmas light sets used line-voltage (120 or 240 volts depending on what country) lightbulbs, similar to those used in refrigerators, connected in parallel. These sets were very power hungry and are used less widely nowadays. Even before that, Christmas trees were illuminated by candles. This is still done rarely, but is not recommended, because it is very dangerous!

One should always unplug a Christmas light set that has no transformer before repairing it. Remember that the electronic controller in such sets is also not line isolated! Animated Christmas light sets, including fiber optic ones should never be watched by persons having photosensitive epilepsy.

The number of strands of continuous light sets that may be safely conjoined varies amongst manufacturers, based on factors such as whether the lights are used indoors or outdoors, whether the lights are miniatures or full sized, and the voltage capacity of the set.

For outdoor light displays, a strand of three connected light sets drawing from a single power source (not necessarily multiple strands from a single outlet or from a multiple ended extension cord) is a safe standard, or a total not exceeding 1000 miniature bulbs, as the number of lights on a single strand may vary by manufacturer.

Standards for indoor use are generally greater due to wiring designed to protect the home and the lack of exposure to the elements. The number of safe bulbs is around 2000 for most manufacturers, though some manufacturers will suggest fewer. Always follow the manufacturer's safety restrictions. If you have questions, consult the manufacturer or an electrician.

Most light sets come with built in fuses to help protect against overheating and to prevent your house's fuses or circuit breakers from being tripped. If you blow a fuse, unplug the strand from the power source and reduce the number of lights immediately. If the strand has nothing attached, or has blown repeatedly, the strand may contain a short and should be discarded. A good rule of thumb is if the fuse does not blow or become hot from use of over one hour (warm is acceptable) than the number of conjoined light sets or other attached devices will be fine.

It should also be noted that many light sets may contain traces of lead, and consumers should wash hands thoroughly after handling these products, especially before eating. Proposition 65 of California requires that if products contain lead or traces of lead then a warning must be printed on packing of products. Be sure to check the label for this and any additional warnings.

Christmas lights - House lights

In the U.S. from the 1960s, beginning in tract housing, it became increasingly the custom to completely outline the house (but particularly the eaves) with weatherproof Christmas lights. The Holiday Trail of Lights is a joint effort by cities in east Texas and northwest Louisiana that had its origins in the Festival of Lights and Christmas Festival in Natchitoches, started in 1927, making it one of the oldest light festivals in the United States.

The rule of thumb for fairy lights when decorating trees is to use between 150 and 300 lights per foot of tree heights.

Christmas lights - Trivia

• Christmas light strings wired in series were often of the type where if one bulb burned out or was loose, an entire string would not illuminate. Development of wiring in parallel and shunts in individual bulb bases were technological (and practical) improvements welcomed by many users.

• In the 1989 film National Lampoon's Christmas Vacation, actor Chevy Chase attempts to follow American family Christmas traditions with elaborate Christmas lights and decorations on the exterior of the family home. His attempt at a "Grand Illumination" for a family reunion is one of the high points of the story. The film has become an annual holiday favorite in many families.

External links

• Indoor & Outdoor Christmas Lights
• George Nelson's Antique Christmas Lights site
• Tacky Christmas Light Tour in Richmond, Virginia
• Christmas lights, the idea of 'less is more' is 'more or less' dead.
• Morris Propp and His Contribution to Electric Christmas Lights

Category: Christmas traditions

Adapted from the Wikipedia article "Christmas lights", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki