Light Bulb Shapes

Light bulb shapes vary, from pear shapes to funnel shapes to tube shapes. Each light bulb type has a designation. Examples include: PAR for parabolic aluminized reflector light bulb or T for tube. Many household halogen light bulbs are a MR16, the MR is for 'metallic reflective' light bulb.
Bulb shapes are derived from these names. Several of the more general classes of bulb types are outlined below.

Light Bulb Shape Types

• A Standard incandescent light bulb shape
• B Candelabra bulb shape
• BR Short reflector style bulb
• C Christmas tree style light bulb shape
• ER Extended reflector light bulb
• F Flame style candelabra bulb shape
• G Globe bulb or circular bulb
• K Narrow reflector light bulb
• MB Halogen bulb
• MR Quartz reflector lamp (low wattage)
• PAR Parabolic Aluminized Reflector (PAR) lamp
• PS Elongated standard incandescent bulb
• R Reflector light bulb style
• S Short bulb style
• T Tube lamp

PAR Light Bulbs: PAR16, PAR20, PAR30 and PAR38

PAR light bulbs utilize a parabolic mirror or reflective surface to focus the light. This results in a great brightness with less energy consumption. Still several factors less effecient than an LED light bulb.

How to Identify Light Bulbs

Light bulbs are measured in several ways. Physical dimensions, amount of light output, wattage consumption are just a few. This post will focus on the physical dimensions of light bulbs and the differing types of bases.

There are four ways of measuring a bulbs physical dimensions:

1) Bulb shape: bulb shapes vary, from pear shapes to funnel shapes to tube shapes. Each has a designation. Examples include: PAR for parabolic aluminized reflector or T for tube. Many household halogen lights are a MR16, the MR is for 'metallic reflective'.

2) Bulb diameter: bulb diameter is measured in 1/8 inches increments at the maximum point of diameter. A PAR30 is 30 eighths of an inch in diameter or 3 3/4 inches. A T8 is 8 eights of an inch in diameter or 1 inch. MR16 is 16 eighths or 2 inches in diameter.

3) Bulb length: bulb length is measured in inches as the Maximum Overall Length (MOL). So a 4 foot florescent tube has an MOL of 48 (inches).

4) Bulb base type: Bases are measured in millimeters. So a typical household screw-in base like E27 (E is for Edison Screw-in) is 27 millimeters in diameter. An E11 candelabra base is an 11 millimeter diameter Edison screw in base. For pinned bases like a florescent tube or a pinned MR16 halogen bulb, the measurement is from the center of one pin to the center of the other pin.