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Lamp bulb, discharge


Artifact no.
40 W Cool White Preheat
Manufactured Date
After 1938
Context Function
A device used to provide illumination by means of an electric current which excites mercury vapor in a glass tube, producing short-wave ultraviolet light that then creates fluorescence, producing visible light.
Context Technical
The Preheat model was an early type of fluorescent lamp. Cathodes had to be pre-heated to electron emitting temperature before the lamp would light. This lamp required the use of a separate starter which supplied several seconds of current flow through the cathodes to pre-heat them between the time the tube was turned on and the time the lamp emitted light.
Context Canada
An example of a lamp bulb used in Canada, part of a large and varied collection of over 7500 electrical items acquired and documented by Ontario Hydro in the 1960s. The collection was thought to be the largest and most comprehensive of its kind in Canada and was donated to the Canada Science and Technology Museum in 1992
Glass tube coated with white phosphor/ metal parts/ synthetic parts
Number of Parts
Artifact Finish
White tube with colourless transparent glass at each end/ metallic and black end caps
Artifact Markings
Black lettering on glass reads 'WESTINGHOUSE/ 40 W COOL WHITE/ PREHEAT'
Artifact Missing
Appears complete
Group 1
Lighting Technology
Category 1
Lamp bulbs
121.0 cm