Light bulb base are teh part of the bulb that connects to the light fixture. The base of the bulb will determine if the bulb will fit into the fixture. Bulbs must have the correct base for the fixture in which they are to be used; otherwise, the bulb wont function within the fixture.
Many people may purchase bulbs that have the correct shape for the fixture, but the base of the bulb may not be the correct size or type for that particular fixture. Thus, people must know the type of light bulb base that is required for the fixture in question before purchasing bulbs for that fixture. There are four primary categories of light bulb bases: screw, bayonet, pin, and tube bases.
Different Types of Light Bulb Bases
Screw bulb bases include a threaded metal cylinder that is used when the bulb is turned into the socket of the fixture. Bayonet bulb bases use pins on the sides of the bulb that lock into the fixture. Pin bases use metal pins that either push into or turn into the socket of the light fixture.
Finally, tube bases use bi-pins at the two ends of the bulb that is used for lighting long areas of a structure, such as a garage. Screw bases begin with the “E” prefix, indicating that the base is of a screw type. Following the prefix is the number that indicates the diameter of the screw base in millimeters.
Small screw bases are used for decorative chandeliers, for instance, whereas larger bases is used for industrial warehouses. Additionally, you must take care when buying screw bulbs; different regions of the world have different voltages in there electrical systems. Bulbs made for the North American electrical system use 120 volts, while European bulbs use 220-240 volts.
Using bulbs that are not design for the voltage of the light fixture may lead to the bulbs failing to light, or, worse yet, to the bulbs causing fires. Pin bases has codes associated with them, such as the “G” or the “GU” codes. Pin bases are used for small spotlights because they are able to fit into tight spaces within the light fixture.
Additionally, some pin bases require a transformer to reduce the electrical current being emitted from the fixture, while others are set to recieve the mains power direct from the electrical system. Thus, people must check the fixture to determine if the pin base bulbs require a transformer; otherwise, the bulbs may fail. Bayonet bases are common in certain parts of the world.
People push and twist bayonet bases into the light fixture. Bayonet bases are not the same than screw bases, and will not fit into a screw base socket. Adapters exist for bayonet bases to be connected to screw bases, but using such an adapter could of void the warranty for the light fixture.
The base code for the bulb will tell you the type of base of the bulb. The letter in the code will indicate the “family” of the bulb, such as if it is screw, pin, or bayonet based. Additionally, the number associated with the base will tell you the size of the base or the spacing of the pins in millimeters.
By removing the old bulb from the fixture and reading the code on the old bulb, a person can ensure that the new bulb they purchase will have a matching base code. By ensuring that light bulbs have the same base as the fixture to which they are to be placed, those bulbs will both function correct and securely within the light fixture.