identify your lightbulb > bulb identification key


STEP 3: Base Shape


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: If bulb comes with a standing “lamp base” or “socket” and cannot be unplugged or unscrewed, it is probably glued in. DO NOT attempt to force it out.


OPTION A: Neck of bulb is plain and has no threaded base but may have two copper wires OR copper strips on opposite sides of the neck. Neck may be found plugged into a standing wooden or plastic “lamp base” or socket. [60a]
OPTION B: Bulb has a short threaded base with two to three threads. [60b]
OPTION C: Bulb has a longer threaded base with five to six threads. [60c]


Pathway History:
  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