With the holiday season here in full swing and the last shopping weekend before Christmas upon us, I’m sure many of you have noticed the vast increase in stringed lights, whether they are hung on a Christmas tree, a house, shrubbery, or even someone’s car. While Christmas lights are a staple of the holiday season, I’m sure many of you have become frustrated when the whole string goes out because one bulb is removed or broken. Here is a brief history of Christmas lights and how they work.
Thomas Edison, the creator of the first practical light bulb and famous electrical engineer, created the first strand of electric lights in 1880, and hung them outside of his Menlo Park Laboratory during the holiday season. Edward H. Johnson, Edison’s friend and partner in the Edison’s Illumination Company, created the first string of lights for a Christmas tree in 1882. He hand-wired 80 red, white and blue lights and draped them around his Christmas tree. At this time electricity was still a new development and many were skeptical. President Grover Cleveland is given some of the credit for spurring the acceptance of indoor electric Christmas lights. In 1895 he requested that the White House Christmas tree be lit up with multi-colored electric light bulbs.
[i] By 1900 department stores were using Christmas lights to decorate their trees and Christmas displays.[ii] In 1903 General Electric began selling pre-assembled kits of Christmas lights, but they were reserved for the well off as they were very expensive and required the services of a wireman, or modern day electrician. While the first string lights were created in the 1880s, it wasn’t until 1917 that Christmas lights for the general public began taking hold. Albert Sadacca and his family owned a novelty lighting company, and Albert suggested to the family that they sell Christmas lights. A few years later, Albert and his brothers had formed the National Outfit Manufacturing Association (NOMA), a trade association. This trade association developed into NOMA Electric Company, and corned the Christmas light market until the 1960s.[iii]
Prior to 1970, many Christmas lights were large incandescent bulbs that consumed a lot of power, generated a large amount of heat, and were very expensive. During the 1970s, mini Christmas lights were introduced. These mini lights are small, 2.5-volt incandescent bulbs, which can be strung in a line and utilize a standard 120-volt outlet. Mini-lights are extremely sensitive to the removal of a bulb because it breaks the circuit, and no lights can be lit. Many have seen blinking Christmas lights. This is caused by one of two ways. First, a blinker light may be installed into the strand. On a blinker bulb there is a bi-metallic strip, and the current runs from the strip to the post to light the filament. When the filament gets hot, the strip bends, breaking the current and causing the bulb to go out. As the strip cools, it returns to its position, reconnecting the post, and re-lighting the bulb. When the blinker bulb is not lit, the entire strand is not getting power, so all the lights blink in unison. Another option is a 16-function controller. A controller box drives the four strands of lights that are interleaved together. The box is very simple, consisting of an integrated circuit and four transistors, one per strand.[iv] By sequencing the transistors you can create a wide variety of effects, whether it’s “running” lights, or lights that blink along to a song.
As you are running around searching for the perfect gift or rushing to your next holiday party, take a moment to stop and enjoy the Christmas lights. If it wasn’t for two brilliant electrical engineers who had the idea of stringing lights together, we may be still using traditional candles in our holiday decor.