Transcript Nernst Glower.ppt

Nernst Glower
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Derived from German chemist Walther
Hermann Nernst, who derived the Nernst
equation.
Used in spectroscopy to provide near infrared
radiation.
They have a large negative temperature
coefficient of electrical resistance and must be
preheated to be conductive.
How it Works
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Basically, a Nernst glower is a cylindrical rod or
tube composed of rare earth oxides such as
zirconium oxide(ZrO2), yttrium oxide (Y2O3)
and erbium oxide (Er2O3).
Platinum leads at the ends of the cylinder permit
the passage of electricity.
Causes light production similar to blackbody
radiation.
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Operated at temperatures from 1500-2000K.
Operates best in wavelengths from 2 to 14
micrometers.
Even at extremely high temperatures, a Nernst
glower is useless in infrared spectroscopy if
wavelength drops well below this range.
Nernst Glower vs. Globar
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The two light sources are similar in many ways,
such as the function and temperature range.
However, the Nernst glower is better used at
shorter IR wavelengths (near IR), whereas
globar is better used at longer IR wavelengths.
Advantages
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Requires less power than a globar
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Lasts a lifetime
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Operates in air
Disadvantages
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Very expensive ($6850)
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Extremely fragile
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Because it is operated in the air, which is an
advantage, if the temperature becomes too high,
it will burn up, which is obviously a
disadvantage.