What is a Bolometer?

            Bolometer is an instrument that is used to measure radiation temperature. It is a kind of Resistance Bridge. Its one arm consists of a blackened metal strip. When the radiations fall on the metal strip the temperature rises. This increase in temperature measured by a bolometer. This is a very sensitive instrument.

Bolometer

            A U.S. scientist, Samuel P. Langely invented this instrument in 1880. In this first bolometer, a Wheatstone bridge was used along with a galvanometer that produced a deflection proportional to the intensity of the radiation. Since then several other thermal devices have been developed but bolometer remains one of the most effective and convenient infrared detectors. It is because it does not need cooling and can be operated with great ease.

            Now the question arises, what is the principle of working of this instrument? The principle on the basis of which a bolometer operates is that a temperature changes is produced by the absorption of radiation this causes a change in electrical resistance of the material used in the fabrication of the bolometer. This change in resistance can be used to sense radiation.

            There are several types of bolometer in use today. One type has two strips bridge the circuit, their electrical resistance changes. The change of resistance can be used to measure the temperature. This instrument is so sensitive that it can detect changes in temperature as small as 0.001 degree centigrade.

            Another type of bolometer known as spectrum bolometer consists of a single strip of metal. It is used for examining the distribution of intensity of radiation in a spectrum.
Labels: , , ,
loading...

EVERGREEN POSTS

  • How does a Battery Torch Work?
                A battery torch is a portable electrical appliance used for lighting. Doctors use it to examine closely the ears, eyes, noses a...
  • Tears come out while weeping
    Why do tears come out while weeping?             You must have noticed that whenever somebody weeps, tears begin to fall from his eyes....
  • One of our Feet Bigger than the Other
    Why is one of our feet bigger than the other?             You may not believe this but our feet differ in size from each other. Have yo...
  • How do Seeds of the Plants get dispersed?
                There are a number of ways in which plants differ from animals but one of the most pronounced differences is that animals can m...
  • Our Ears detect Sound
    How do the ears detect sound? We hear a number of sounds every day. Some are pleasant while others are not. On the basis of its structure...
  • Which Fish is called the King of Fishes?
                Just as lion is called the king of beasts, the same way shark can be called the king of fishes. It is the fastest and the most ...