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The Nernst Lamp

Posted: Sun Jun 17, 2018 6:36 pm
by Paul
Intrigued by Gav's picture of a Nernst lamp on the gallery, I was keen to find out how they worked. Having looked around online, this is what I can find:

The Nernst lamp (also known as an incandescent "glower" lamp) uses a small ceramic rod, heated to incandescence, to provide light.
The ceramic glower is not enclosed in a glass envelope as it does not oxidize like metal and does not need to be run in a special atmosphere.
The glower in the lamp could be replaced and often outlasted incandescent lamps of the era, making it popular in places where maintenance was an issue.
The lamp has a simple resistive ballast in the base, consisting of a resistor wire in a glass bulb.
Electricity is applied to the heater tubes, sat adjacent to the glower, which raise in temperature to the point of glowing slightly red.
This heated the glower until it reached a temperature where the resistivity of the glower material dropped to the point where current would begin to flow through it. A contactor or switch would cut the power to the heater tubes, leaving power to run through only the glower.

The Nernst lamp produced a nice, almost of daylight appearance light, close to natural daylight in spectral terms.

Re: The Nernst Lamp

Posted: Sun Jun 17, 2018 6:42 pm
by Tom
What an interesting concept! I believe it was quite short lived and was soon displaced by both incandescent arc and discharge lamps?

Re: The Nernst Lamp

Posted: Sun Jun 17, 2018 10:10 pm
by LinearSLI-H
That does sound slightly ahead of its time :shock:, love to see one working first hand.

Re: The Nernst Lamp

Posted: Wed Jun 20, 2018 12:29 pm
In Andrew Pullen (the “globe collector”) short movie you can see him “blowing out” a lamp that looks like a Nernst lamp.