Incandescent Light Bulb Types

The world of light bulbs is vast, and can be confusing. See our earlier post Light Bulbs 101: What am I Looking for? for our intro course. If you already visited that page, we will dive a little deeper!

1. Base

Every light bulbs have a base. Some light bulbs, usually halogen, will have a more complicated and unfamiliar base, such as a bi-pin or a GU10 like this one:

If your bulb is an incandescent, you will typically have six different base types.

Mogul- The largest size, reserved for high wattage bulbs.

Standard (also known as Edison or Medium)-

Looks familiar? This is your standard sized bulb with the "Edison" base. This will fit into most regular sockets, and most people have lamps or fixtures that carry this size.

Candelabra- 

This size is featured a lot in chandeliers and wall sconces. They are typically reserved for smaller and more decorative bulbs (like this torpedo bulb as shown), and usually gives off less light. We carry these from 10 watts up to 60 watts, although you will typically use only a 40 watt maximum in most fixtures.

European-

Obviously, these go into European fixtures.
 

Intermediate-

Just like it sounds, it's a size in between candelabra and standard. Not used as much, you'll find this size in some appliances, indicator bulbs and tubular bulbs.

Bayonet- 

 

There are a few different types and sizes of bayonet bases, and these aren't very common in light fixtures.
 
2. Sizing and Shapes

Light bulb sizes and shapes are standardized in the United States with a simple naming system. Just like the bases have a letter/number code. Incandescent bulb size is determined by measuring the bulb's diameter at it's widest point. The measurement is written in 8ths of an inch increments. 

For example, your typical looking light bulb:

 

Is a type A look that is 2 3/8 inches in diameter. The 2 3/8 is translated into 19/8", so the bulb type is "A19".

"A"s are the bulb shape that you always think of when thinking about light bulbs.

"G"s are globe bulbs. Used with vanity mirrors in bathrooms, in pop culture you think of broadway or dressing rooms for theatres.

    
"B10"s are torpedo shaped.

 

"BA"s are flame tipped.

 

Other important bulbs shapes:

R's and BR's are spotlight bulbs.

PAR's are a special type of spotlight bulb. More durable and used outdoors or indoors. Typically halogen.

Of course there are many other types of bulb shapes!

3. Coating

The coating of the bulb determines several lighting characteristics. The amount of light that shines, the direction and width of the beam, the color/mood of the light and how much glare exists. For instance, on a see through fixture, you may not want to use a clear bulb that will blind people in the room! But clear might be apappropriate for stronger lighting. 

Clear-

This type shines in a whitish yellow, broadcasts the light and produces significant glare. Most efficient for the amount of energy output.      

Frosted-

A softer light, typically more yellow in tone. Decorative, and can produce a lot of light, but needs a higher wattage to do so.

Satin White- 

Produces a specific soft white light, very decorative but doesn't broadcast light as well.

Silver Crowned-

The bulb is dipped in silver at the bottom. Great for a pendant! Keeps glare at bay and looks great in a modern fixture.

      
Colors- Can cover with any color to produce reds, blues, yellows, etc. Good for special events, parties or unique fixtures.  




In the world of light bulbs, it's easy to get confused. Follow these tips and you'll soon be a light bulb expert! 


Acknowledgments: Special thanks to Satco Products for providing us this information in their products guide, and for all of their awesome light bulbs!