Colorful Christmas lights for the outdoors are mostly made using C9 bulbs. These days, LED series lights are becoming increasingly popular due to the low power consumption, light weight and flexibility.However, these strings using mini lights are not long lasting and many people find themselves hunting for a new set of light strings every other season. For long life and shear ruggedness, nothing beats the C9 lights, which have a history of more than 80 years of outdoor usage. C9 lights are available with the old incandescent bulbs as well as with LED bulbs. So, next time you buy LED light strings for outdoor use, make sure you buy C9 LED Christmas Light Strings and not the strings with the tiny C6 or C7 or other bulbs, which are for indoor use.
Usually, two types of these light bulbs are used. The first are the milky coated, opaque lights, called "ceramic" lights.The second type are the clear, see-thru lights called "transparent" lights. The ceramic lights are preferred by most folks as the lighting effect is softer compared to the glare of the transparent lights.
The older bulbs are "incandescent" bulbs with tungsten filaments. Since the C6, C7 and C9 terms are for the size, modern LED bulbs in similar sized fittings can also be called as C6 lights or c7 lights or c9 lights. The advantage of this universal terminology is , irrespective of the make or brand of your Christmas Light Strings, you can get replacement bulbs of the same size - c6 or c7 or c9 and expect them to fit into the series lights. The C7 and C6 bulbs are distinctly smaller than the C9 bulbs and are only meant for indoor use.
Another point to note is the base of the bulb which can be "candelbera" base or intermediate base. In Europe, the bases are different such as E12 and E14. You have to get socket reducers if you want to fit bulbs with a particular base into strings of another base.
History of C9 Lights
General Electric first introduced tungsten filament series lights for the public in 1916. These were known as G8 / G9 lamps - Globular lamps, 8/9" or 9/9" in diameter. The conical shaped "MAZDA" bulbs, named after Ahura Mazda appeared in 1919. C6 cone lamps were introduced in 1924 and remained in use unchanged till 1974! (Of course, the C6 christmas lights these days are all made of LED lights) The C6 was followed by the C7, but both these were for indoor use. So, in 1927, GE brought in the C9 for outdoor use with a larger bulb and more water resistant wiring. And these are still in use, the technology practically unchanged!Terminology
Usually, two types of these light bulbs are used. The first are the milky coated, opaque lights, called "ceramic" lights.The second type are the clear, see-thru lights called "transparent" lights. The ceramic lights are preferred by most folks as the lighting effect is softer compared to the glare of the transparent lights.
Another point to note is the base of the bulb which can be "candelbera" base or intermediate base. In Europe, the bases are different such as E12 and E14. You have to get socket reducers if you want to fit bulbs with a particular base into strings of another base.
