Nernst glower
Encyclopedia
The Nernst glower is an obsolete device for providing a continuous source of (near) infrared
radiation for use in spectroscopy
. Typically it was in the form of a cylindrical rod or tube composed of a mixture of certain oxides such as zirconium oxide (ZrO2), yttrium oxide (Y2O3) and erbium oxide (Er2O3) at a ratio of 90:7:3 by weight. They operated by being electrically heated to about 2000 °C. Initially they required external heating because the material is an insulator
at room temperature.
It has been replaced by a similar device known as a Globar
made of silicon carbide
(SiC) that operates at about 1100 °C. The Globar does not require an external preheater as it is an electrical conductor at any temperature. It is also better suited for use in evacuated systems.
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
radiation for use in spectroscopy
Spectroscopy
Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...
. Typically it was in the form of a cylindrical rod or tube composed of a mixture of certain oxides such as zirconium oxide (ZrO2), yttrium oxide (Y2O3) and erbium oxide (Er2O3) at a ratio of 90:7:3 by weight. They operated by being electrically heated to about 2000 °C. Initially they required external heating because the material is an insulator
Electrical insulation
thumb|250px|[[Coaxial Cable]] with dielectric insulator supporting a central coreThis article refers to electrical insulation. For insulation of heat, see Thermal insulation...
at room temperature.
It has been replaced by a similar device known as a Globar
Globar
A Globar is a silicon carbide rod of 5 to 10 mm width and 20 to 50 mm length which is electrically heated up to . When combined with a downstream variable interference filter, it emits radiation from 4 to 15 micrometres wavelength...
made of silicon carbide
Silicon carbide
Silicon carbide , also known as carborundum, is a compound of silicon and carbon with chemical formula SiC. It occurs in nature as the extremely rare mineral moissanite. Silicon carbide powder has been mass-produced since 1893 for use as an abrasive...
(SiC) that operates at about 1100 °C. The Globar does not require an external preheater as it is an electrical conductor at any temperature. It is also better suited for use in evacuated systems.