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Resistance thermometers, also called resistance temperature detectors (RTDs), are sensors used to measure temperature. Many RTD elements consist of a length of fine wire wrapped around a heat-resistant ceramic or glass core but other constructions are also used. The RTD wire is a pure material, typically platinum (Pt), nickel (Ni), or copper ...
The Callendar–Van Dusen equation is an equation that describes the relationship between resistance (R) and temperature (T) of platinum resistance thermometers (RTD). As commonly used for commercial applications of RTD thermometers, the relationship between resistance and temperature is given by the following equations.
The integrated circuit sensor may come in a variety of interfaces — analogue or digital; for digital, these could be Serial Peripheral Interface, SMBus/I 2 C or 1-Wire.. In OpenBSD, many of the I 2 C temperature sensors from the below list have been supported and are accessible through the generalised hardware sensors framework [3] since OpenBSD 3.9 (2006), [4] [5]: §6.1 which has also ...
Finding temperature from resistance and characteristics [ edit ] The equation model converts the resistance actually measured in a thermistor to its theoretical bulk temperature, with a closer approximation to actual temperature than simpler models, and valid over the entire working temperature range of the sensor.
These change their electrical resistances as a predictable function of temperature, making it useful as a thermometer with electrical output. Balco has a temperature coefficient of resistance of 0.00518 Ω/Ω/°C nearly as high as that of pure nickel (0.00672) but with much better linearity.
The SI unit of absolute thermal resistance is kelvins per watt (K/W) or the equivalent degrees Celsius per watt (°C/W) – the two are the same since the intervals are equal: ΔT = 1 K = 1 °C. The thermal resistance of materials is of great interest to electronic engineers because most electrical components generate heat and need to be cooled.
Original data from the 1911 experiment by Heike Kamerlingh Onnes showing the resistance of a mercury wire as a function of temperature. The abrupt drop in resistance is the superconducting transition. The electrical resistivity of a metallic conductor decreases gradually as temperature is lowered.
The higher the coefficient, the greater an increase in electrical resistance for a given temperature increase. A PTC material can be designed to reach a maximum temperature for a given input voltage, since at some point any further increase in temperature would be met with greater electrical resistance.