A bolometer is a device for measuring the power of incident electromagnetic radiation via the heating of a material with a temperature-dependent electrical resistance.

Power P from an incident signal is absorbed by the bolometer and heats up a thermal mass with heat capacity C and temperature T. The thermal mass is connected to a reservoir of constant temperature through a link with thermal conductance G. The temperature increase is ΔT = P / G.

The term bolometer is also used in particle physics to designate an unconventional particle detector.

A microbolometer is a specific type of bolometer used as a detector in a thermal camera.

After applying microwave power, the bias current is reduced to return the bolometer to its resistance in the absence of microwave power.

Alternatively the source of power to be measured can be used to heat a sensor whose temperature, which depends upon power dissipated, is measured ( bolometer ).

A microbolometer is a specific type of bolometer used as a detector in a thermal camera.

The temperature change of the bolometer results in a change in resistance which is measured and transformed into an electric signal.

With support from ground-based observations done using the submillimeter bolometer cameras on the Atacama Pathfinder Experiment radio telescope ( November 29, 2009 ) and the Mayall ( Kitt Peak ) and Magellan telescopes ( December 4, 2009 ), it was determined that the patch looks black not because it is an extremely dense pocket of gas, but because it is truly empty.

Langley invented the bolometer, an instrument for measuring infrared radiation.

The radiant energy of the incident beam was deduced from its heating effect upon a small blackened silver disk, which was found to be more reliable than the bolometer when it was first used.

His publication in 1890 of infrared observations at the Allegheny Observatory in Pittsburgh together with Frank Washington Very along with the data he collected from his invention, the bolometer, was used by Svante Arrhenius to make the first calculations on the greenhouse effect.

The first bolometer used by Langley consisted of two platinum strips covered with lampblack.

A bolometer can be used to measure power at microwave frequencies.

Planck employs both HEMT radiometers as well as bolometer technology and will measure the CMB on smaller scales than WMAP.

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The older continuum single pixel UKT14 bolometer receiver was replaced in the 1990s by the Submillimetre Common-User Bolometer Array ( SCUBA ).

The average response time of the bolometer allows convenient measurement of the power of a pulsed source.

Samuel Pierpont Langley ( August 22, 1834, Roxbury, Massachusetts – February 27, 1906, Aiken, South Carolina ) was an American astronomer, physicist, inventor of the bolometer and pioneer of aviation.

The bolometer has enabled scientists to detect a change of temperature of less than 1 / 100, 000 of a degree Celsius.

Spiderweb bolometer for measurements of the cosmic microwave background radiation.

Conceptual schematic of a bolometer.

A bolometer consists of an absorptive element, such as a thin layer of metal, connected to a thermal reservoir ( a body of constant temperature ) through a thermal link.

By 1880, Langley's bolometer was refined enough to detect thermal radiation from a cow a quarter of a mile away.

The hot electron bolometer ( HEB ) operates at cryogenic temperatures, typically within a few degrees of absolute zero.

Planck employs both HEMT radiometers as well as bolometer technology and measures the CMB anisotropies at a higher resolution than WMAP.

His most important work was in measuring the temperature of the surfaces of the Moon and other planets using a bolometer.

He is no dextrous-fingered college boy but rather a dedicated, humble, and bashful apostle of this instrument.

Carl says it is the greatest poem ever written to the guitar because he has never heard of any other poem to that subtle instrument.

Properly used, the present book is an excellent instrument of enlightenment.

The time is now ripe, indeed overdue, for the vigorous development of its non-military potentialities, for its development as an instrument of Atlantic community.

Conceived as an organ of economic cooperation, there is no reason why O.E.C.D. cannot evolve into a broader instrument of union if its members so desire.

Only when a concert of nations rests on the positive foundations of shared goals and values is it likely to form a viable instrument of long-range policy.

The transducer is a null-type instrument and employs a stretched diaphragm, 0.001 in. thick and 1 in. in diameter.

Such an instrument is expected to be especially useful if it could be used to measure the elasticity of heavy pastes such as printing inks, paints, adhesives, molten plastics, and bread dough, for the elasticity is related to those various properties termed `` length '', `` shortness '', `` spinnability '', etc., which are usually judged by subjective methods at present.

There is much research evidence to validate the use of the instrument in differentiating individuals who are likely to manifest anxiety in varying degrees.

The instrument is shown in Fig. 1 and consists essentially of a hard, sharp, tungsten carbide knife which is pushed along the substrate to remove the coating.

Since the removal force is a function of coating thickness, a differential transformer pickup has been incorporated into the instrument to accurately measure film thickness.

If a wedge-shaped coating of increasing thickness is removed from a substrate by an instrument like the Hesiometer with a knife of constant rake angle, a number of removal mechanisms are often observed which depend upon the thickness of the coating.

A reflectance-measuring instrument may be desirable to measure cleaning, whereas Soxhlet extraction is necessary to measure grease removal.

High-gain, photoelectronic image intensification is applied under conditions of low incident light levels whenever the integration time required by a sensor or recording instrument exceeds the limits of practicability.

Since interviewing is the basic therapeutic and diagnostic instrument of modern psychiatry, the recording of interviews for playbacks and study has been a boost of Redstone proportions in new research and training.

If the voice is just a shade less glorious than it used to be, it is still a beautiful instrument, controlled and flexible.

Another variation is that Apollo played his instrument ( the lyre ) upside down.

In music an " answer " ( also known as countersubject ) is the technical name in counterpoint for the repetition or modification by one part or instrument of a theme proposed by another.

Using visual imagery of a soroban, one can arrive at the answer in the same time as, or even faster than, is possible with a physical instrument.

The Spectrogram produced by such an instrument is a graphical display of the time varying pressure level and frequency profiles which give a specific acoustic signal its defining character.

A cup-shaped mouthpiece carved out of a block of hard wood is added and the instrument is complete.