Since the evolution of bulbs in the late 1800s, nothing much has changed as far as the basic design of the lamp socket adapter goes. There might be slight differences in sockets in terms of materials and sizes but they all share similar basic forms. Most of the lamp sockets are compatible with CFL and LED bulbs. However, some bulbs are non-dimmable and only the 3-way light bulbs (incandescents) augur well with 3-way lamp sockets. Here are some tips and tidbits.
The standard size of a lamp socket is referred to as the Edison base. These sockets are useful in a number of applications such as chandeliers, floor lamps, ceiling fixtures, and table lamps. Standard base sockets have an interior diameter of about 1”. The other size is the candelabra which is common among decorative fixtures with numerous bulbs. It measures about 7/16” interior diameter opening. They are smaller than the standard sockets while the selection of bulbs is more stylish. Slightly bigger than the candelabra is the intermediate sockets; but smaller than the standard. This size is rare and is normally found in Asia, Europe, and Central America. The diameter is about 5/8”. Bigger than the candelabra is the French socket which originates from France. It is used in the French-size bulb and is used mostly in decorative lamps. The interior opening diameter of a French-size base socket is 9/16”. Lastly, we have the mogul size whose diameter opening ranges between 1” and 9/16”
In case you get an unfavorable socket size for your lamp, you can use a light bulb socket adapter to make the socket conform to the size of the bulb. This is very useful in situations where the lamp has a peculiar size e.g. the French an intermediate size. Adapting the socket enables you to apply common bulb sizes like the candelabra.
One of the styles commonly used in high-intensity light is the halogen socket. You will find them in such places as display cases, jewelry shops, kitchens, and in floodlights. Another common style is the keyless socket which does not feature a built-in switch and they need a lamp for a switch or a wall switch. Keyless sockets are ideal for hanging lighting fixtures on wall-mounted switches.
It is very important for you to find the perfect design, material, and size of a light bulb adapter for your lamp.