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The output of a thermopile is usually in the range of tens or hundreds of millivolts. [7] As well as increasing the signal level, the device may be used to provide spatial temperature averaging. [8] Thermopile, composed of multiple thermocouples in series. If both the right and left junctions are the same temperature, voltages cancel out to zero.
This output voltage is directly proportional to the power of the incoming radiation. [10] Since a large number of thermopiles are typically connected in series, voltages of several μV to V are reached. In general, a thermopile sensor consists of three elements: an absorber, the sensor element and a cooling body to dissipate the incoming heat.
Type-B thermocouples produce the same output at 0 °C and 42 °C, limiting their use below about 50 °C. The emf function has a minimum around 21 °C (for 21.020262 °C emf=-2.584972 μV), meaning that cold-junction compensation is easily performed, since the compensation voltage is essentially a constant for a reference at typical room ...
A thermopile sensor which is sensitive to radiation in a broad range from 200 nm to 100 μm; A silicon dome or window with a solar blind filter coating. It has a transmittance between 4.5 μm and 50 μm that eliminates solar shortwave radiation. A temperature sensor to measure the body temperature of the instrument.
A thermopile pyranometer (also called thermo-electric pyranometer) is a sensor based on thermopiles designed to measure the broad band of the solar radiation flux density from a 180° field of view angle. A thermopile pyranometer thus usually measures from 300 to 2800 nm with a largely flat spectral sensitivity (see the spectral response graph ...
The typical efficiency of TEGs is around 5–8%, although it can be higher. Older devices used bimetallic junctions and were bulky. More recent devices use highly doped semiconductors made from bismuth telluride (Bi 2 Te 3), lead telluride (PbTe), [10] calcium manganese oxide (Ca 2 Mn 3 O 8), [11] [12] or combinations thereof, [13] depending on application temperature.
The Seebeck coefficient (also known as thermopower, [1] thermoelectric power, and thermoelectric sensitivity) of a material is a measure of the magnitude of an induced thermoelectric voltage in response to a temperature difference across that material, as induced by the Seebeck effect. [2]
Where is the sensor output and is the calibration constant, specific for the sensor. General characteristics of a heat flux sensor As shown before in the figure to the left, heat flux sensors generally have the shape of a flat plate and a sensitivity in the direction perpendicular to the sensor surface.