Accuracy platinum sensors

Platinum sensors are currently useful because of their potential accuracy and long-term stability in this temperature range. These sensing elements use the... 

The RTD sensor is based on the fact that the resistance of some metals changes markedly with temperature, whereas the resistance of platinum, the metal most commonly used in RTDs, is extremely stable. Its variation in temperature is both repeatable and predictable to a high degree of accuracy. In the past, TCs offered major cost advantages but with the advent of low-cost solid state dc amplifiers, the use of RTDs has become more realistic. 

In order to measure the temperature with accuracy, researchers have focused their efforts on the integration of sensor strips within a textile stmcture. To do so, they used polymeric film, mostly Kapton (Ataman et al., 2011) as base substrate, on which they deposited thin metal layers. Techniques of photolithography, inkjet printing or spin coating have been used and combined to create the desired pattern. The choice of metallic materials is wide from silvCT, gold, titanium and platinum. 

Figure 16 Power-compensation DSC schematic depicting individual platinum heaters and sensors. Power-compensation DSC is typically used for very exact calorimetry work which demands accuracy as well as precision. It is used for fast quenching experiments such as subtle determination as well as melting studies and specific heat studies. It is also used for routine analysis.

RTDs are used in a great variety of applications. At one extreme, carefully-designed platinum RTDs are used in the very definition of temperature between 13.8033 K and 961.78 °C [2], because of their potential for extreme stability and accuracy (uncertainties of better than 1 mK). At a more practical level, commercial RTDs are widely used for industrial and research applications from 14 K to around 600 - 700 C, with typical absolute accuracies of around 0.15 K to 2 K uncalibrated, or 0.1 K or better after calibration. Bare platinum RTDs also have a long and illustrious history as velocity sensors for fluid flow, a technique known as hot-wire anemometry. More recently, special RTD configurations have also been developed to measure the thermal properties of fluids and solids [7-9]. 

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