A Hefner lamp is a measuring instrument used to measure the luminous intensity of a light source. It's a historical lamp originally developed for scientific purposes , specifically in laboratories and industrial applications, to determine light intensity.
Function and use :
- The Hefner lamp was used to measure the luminance or light intensity of different light sources in candelas (the unit of luminous intensity).
- The instrument worked by producing a controlled flame that was used as a standard against which to compare other light sources.
- At the time it was developed, it was an important way to calibrate the light output of gas lamps, candles, and other light sources.
Naming :
The lamp is named after the German scientist Hermann von Hefner-Alteneck (1851–1904), who improved the Hefner lamp in the late 19th century and used it to measure light intensity in his research into lighting technologies.
Technical operation :
- The lamp contains a small burner, often a candle or gas flame, which is compared with other light sources. The intensity of the Hefner lamp was therefore known and used as a reference for measuring the brightness of other lamps.
- The lamp had a precise construction that ensured that the flame was always consistent in intensity, allowing for reliable measurements of light intensity.
Contemporary application :
Although the Hefner lamp was originally widely used in the 19th and early 20th centuries , it has largely been replaced today by more modern, electronic light meters and photometers , which can take much faster and more accurate measurements without the use of a physical light source such as a flame.
Summary :
The Hefner lamp was a historical lamp used to measure luminous intensity , primarily in scientific and industrial applications. It was named after the scientist Hermann von Hefner-Alteneck , who developed it as a measuring instrument. Today, the Hefner lamp is being replaced by digital and electronic measuring instruments.