While the numbers indicate the diameter but the optional letter indicates the length of the bulb. Note, as a rule of thumb, traditionally C9 bulbs “always” have E17 bases so many times, the base is also referred to as C9 as well. Bulbs with these bases are the most popular of all screw base bulbs. It’s easy enough to look at the bulb that you need to replace and shop for a bulb with a similar looking base, but how will you know for sure if the bases are identical? Source – wikipedia.org. Use this handy guide to identify different types of light bulb bases that apply to incandescent, halogen, high-intensity discharge, fluorescent, and LED light bulbs. You might also hear them referred to as Edison base light bulbs. This post covers screw bases. Many bulbs with these bases are designed to mimic the look of a candle flame. Bulbs with this shape have a bulged base that attenuates to a rounded tip. An E26 bulb, therefore, is any bulb or lamp that utilizes the E26 cap or base for mounting and electrical contact. Or if we’re talking about the G series two-pin base, it would be the distance between the two pins measured in millimeters. This normally is in the form of letters followed by a number followed by an optional letter. Notify me of follow-up comments by email. This article will briefly cover each category and provide you some useful information so that you actually know which type of bulb you need for different situations and fixtures. It’s most likely E26 which is the most common base. For instance, A-19 bulb means that it is s “A” type and the diameter would be 19/8″. However, bulbs have been evolved significantly and now you have them in numerous categories divided by shapes, sizes and base types. Let’s learn more about lamp bases, which come in all shapes and sizes. LEDwatcher © 2015 - 2021. Is an E26 bulb the standard base size? It is found on smaller light bulb shapes such as S11, R12, and T6 light bulbs. Thank you again SO much for writing such a great and in-depth article! The bulbs have right-hand threaded metal bases (caps) which screw into matching threaded sockets (lamp holders). None of them have any base designation on box or bulb. LED Downlights: Crisp Illumination for Commercial and Home Applications, Planning for an LED Landscape Lighting Installation, Green LED Lights: Therapy for Migraines/Chronic Pain, How to Make a DIY Christmas Wreath With LED Strip Lights, How to Create Your Own LED Light Fixture: Aluminum Channels, Four Ways to Brighten up Your Thanksgiving. Find the light bulb base type you’re looking for with this visual chart- detailed illustrations of general bases, fluorescent bases and specialty halogen base types. The number refers to the diameter of the base in millimeters. There are four commonly used thread size groups for lamps: Candelabra: E12 North America, E11 in Europe. The main diameter classifications are: As for the length, the bulbs are divided into S (short) and L (long) categories but not always you will see the length indicator mentioned in the product description. The first letter or letters indicate the shape. E27 Medium A little larger than the common E26 medium base, this bulb base can still be used in most applications. The respective parameters (shape, size and base type) appear on the package of the product. PAR (parabolic aluminized reflector) bulbs: PAR20, PAR38, PAR40. Screw bases are the most common light bulb base. C7 bulbs have E12 Candelabra bases while C9 bulbs have E17 Intermediate bases. Basic Shapes for Christmas light and outdoor string light bulbs They’re also found in ceiling fan light fixtures. Have you ever found yourself shopping for light bulbs but with no clue as to what will fit your fixture? The intermediate E17 base is not very common. For LEDs, the PAR designation is used for defining the shape since most of the LEDs lack any have a reflective lower surface. Modern light bulbs can be used in a variety of fixtures, and each fixture has its own particular requirements of size and shape of the bulb that it is compatible with. What are PIR Lights and Where They are Used? For bulbs powered by AC current, the thread is generally connected to neutral and the contact on the bottom tip of the base is connected to the "live" phase. It is used in most incandescent, halogen, CFL, CCFL, and HID light bulbs. In its root meaning, though, this is what it is: an object shaped like a flower bulb which produces light. You might also hear them referred to as Edison base light bulbs. Most common light bulb uses, including lamps, recessed flush mount flood lights are going to have one of the first three base types shown above. Coronavirus (COVID-19) Update: Bulbs.com is committed to health and safety. Light Bulb Bases. In an incandescent or halogen screw base light bulb, two contact wires link the filament to the base where the electrical voltage is connected to the bulb. The second letter designates the number of pins or contacts on the lamp. PAR (parabolic aluminized reflector) spotlight and flood light bulbs: PAR16, PAR20, PAR30, PAR38, BR (bulged reflector) spotlight and floodlight bulbs: BR20, BR30, BR40. The most familiar is the Edison screw base found on most incandescent bulbs and many halogen, compact fluorescent, HID and now LED bulbs. The second letter designates the number of pins or contacts on the lamp. From Wikipedia on the Edison Screw Base: "The Edison screw fitting is a system of screw mounts used for light bulbs, developed by Thomas Edison and licensed starting in 1909 under the Mazda … That usually is listed somewhere on the bulb as well as on the packaging. Tags: cfl bulbshalogen bulbshid lampshigh pressure sodium vapor lampsled bulbsmetal halide lamps. Intermediate: E17 North America, E14 (Small ES, SES) in Europe. You need to know the technical name for bulb bases. C-shaped bulbs look very similar to holiday lamps. But how can I tell if the bulb I am holding in my hand is an E-10, E-27, E-40? Screw bases are made in several sizes, and on the packaging you will see that they are referred to by a descriptive name and size. All Rights Reserved. The most common bulb base in the US is the screw medium E26 base. Screw-in bases, also known as Edison bases and light bulb sockets are used through out the world. What are Light Dimmers and Which Type of Light Bulbs are Dimmable? The most common screw base sizes are E5, E-5, E10, E-10, E11, E-11, E12, E-12, E14, E-14, E17, E-17, E26, E-26, E27, E-27, E39, E-39, E40 and E-40. However, only three of all the shapes are widely used for everyday purposes (e.g. Wow. It refers to 26 millimeters (which is 1 inch). A light bulb’s series indicates its shape, followed by a number code that indicates the light bulb’s diameter in millimeters or one-eighths of an inch, depending on the type. The cap or base of a light bulb joins the bulb to the lamp socket in order to provide an electrical connection. 243 Stafford St. Worcester, MA 01603. Look at your fixture to determine its base type. A normal household light bulb is on average a 60 watt light bulb. When searching for replacement bulbs, we were having a difficult time finding the right type and especially size that would fit between the bulb base, and the metal soffit above the base. When thinking about the image of a typical bulb, most of the people picture that one sort of bulb many of us have been using all our childhood. The mogul pre-focused (MPF) base is similar to the screw base in that it connects the filament to the base with two soldered … ER – Extended reflector light bulb shape; K -Krypton or narrow reflector light bulb shape; PS – Elongated standard incandescent bulb. It’s the traditional A-type bulb. If you do not see the base type you are looking for, give us a call at 800.784.1998, and we can help you locate the correct bulb. Altogether you can divide all the bulbs into 6 base types: Light bulb base types. Light bulbs are identified by the diameter, length, shape, and screw type. Indeed, many lamps have their own unique base. The first letter designates the shape or form of the base, the numbers represent either the width of the base or the distance between the pins. My wife and I have installed new outdoor ceiling fans which require special candelabra bulbs. Most packaging for fan bulbs do not provide all the specifications needed or provide enough detail to make a purchasing decision. 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