Naming Conventions for Light Bulb Shapes
Lighting lamps and light bulbs are described by a shape and diameter and length designation. This normally is in the form of letter(s) followed by a number followed by an optional letter. The first letter(s) indicate the shape, the numbers indicate the diameter and the final, optional letter can designate the length.
Lightbulb shape examples include: PAR for Parabolic Aluminum Reflector light bulb or T for Tube. Many household halogen light bulbs are a MR16 for Metallic Reflective.
Sizes are referenced by a number that follows the shape. In the US these numbers indicate the maximum diameter in eighths of an inch. In other parts of the world this number will designate the diameter in millimeters. An example of a US bulb is the R20, this is 20/8 or 2.5" in diameter. An example of a metric measure is the A19 which is the typical household incandescent light.
Sample LED Light Bulb Shape Designations:
- A Standard household incandescent light bulb shape
- B Bulged bulb shape
- BT Bulged or Blown Tubular bulb shape
- BR Short reflector style light bulb
- C Candle or Conical bulb shape
- CP Crystalline Pear bulb shape
- E Ellipsoidal bulb shape
- ER Extended reflector light bulb shape
- F Flame style candelabra bulb shape
- G Globe bulb or circular bulb
- HK Hexagonal Candle
- K Krypton or narrow reflector light bulb shape
- MB Halogen bulb
- MR Quartz reflector lamp (low wattage)
- P Pear bulb shape
- PAR Parabolic Aluminized Reflector (PAR) lamp
- PS Elongated standard incandescent bulb
- R Reflector light bulb style
- S Strait Sided bulb style
- T Tube lamp shape
Here are some standard diameter sizes:
- 8 = 1 inch Example: T8
- 11 = 1.375 inches Example: MR11
- 16 = 2 inches Example: MR16
- 20 = 2.5 inches Example: R20
- 30 = 3.75 inches Example: PAR30
- 38 = 4.75 inches Example: PAR38
Length designations include:
- S for short
- L for long
Source:
http://www.eaglelight.com/category/lighting_tutorials.bulb_shapes/
