A Nernst glower, also known simply as a Nernst lamp or Nernst filament, is a type of incandescent lamp or radiant heater based on the Nernst effect. It was invented by the German physicist and chemist Walther Nernst in the late 19th century.
The Nernst glower operates on the principle of thermal radiation resulting from the heating of a ceramic rod to high temperatures. The ceramic rod, typically made of zirconium oxide or other refractory materials, serves as a resistive element. When an electric current passes through the ceramic rod, it heats up due to its resistance, and it emits infrared radiation.
Key features and characteristics of the Nernst glower:
Ceramic material: The choice of a ceramic material with high melting point and stability is essential. Zirconium oxide (zirconia) is a common material used for Nernst glowers.
Infrared emission: Nernst glowers are known for their efficient emission of infrared radiation. The emitted radiation covers a broad spectrum, including the infrared region.
Applications: Nernst glowers have been historically used in various applications, including spectroscopy, infrared spectroscopy, and as a calibration source for infrared detectors. They are particularly useful in applications where a stable and controllable infrared radiation source is needed.
Temperature control: The temperature of the Nernst glower can be controlled by adjusting the electrical power supplied to it. This control over temperature is important in applications requiring specific infrared wavelengths or intensities.
Stability: Nernst glowers offer stability and longevity compared to some other types of incandescent lamps. Their durability and predictable performance make them suitable for certain scientific and industrial applications.
It's important to note that while Nernst glowers have been widely used historically, newer technologies and sources, such as tungsten-halogen lamps and light-emitting diodes (LEDs), have become more common for many applications. Nonetheless, the Nernst glower remains relevant in specific contexts, especially those requiring precise control over infrared radiation emissions.