identify your lightbulb > bulb identification key


STEP 3: Un-tipped, Inside Frosted Bulbs
[Bulb is entirely frosted on the inside]

Select the option most resembling your bulb from the drop-down menu to proceed to the next step. Please consult "option descriptions" for detailed info.


[The drop-down menu can be re-set by refreshing your browser window.]


FULL OPTION DESCRIPTIONS / IMAGE GLOSSARY: [Option titles are also linked to proceed to the next step.]

Note: To see the filament of an inside frosted lamp, or a soft white lamp, shine a flashlight through the bulb from the back and look for the shadow of the filament.


OPTION A: Bulb is entirely frosted inside, with a smooth surface on the outside of the bulb.  Bulb should have a pearl-like color in appearance.  This is an Inside Frosted Light Bulb, which was introduced in 1925.  Filament is made of either a single or double coiled tungsten filament and mounted [see A91 or see A118] (i.e., either horizontally or vertically).  Single-coiled inside frosted light bulbs were manufactured starting in 1925.  Double-coiled were introduced in 1935.  If bulb shows two filaments and/or has three different wattages etched on top of bulb, bulb is a three-way inside frosted light bulb introduced in 1933 [see Figure 209t?]. key no. [540a]




Pathway History:
START
2 || Untipped-Bulb-Options

3 || Untipped-Inside-Frosted

  thomas edison > website navigation thomas edison > home page thomas edison > timeline : early life thomas edison > timeline : inventing the incandescent lamp thomas edison > timeline : after lighting thomas edison > timeline : legacy of invention thomas edison > classroom thomas edison > interactive modules