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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.
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 ...
is the temperature (in kelvins), R {\displaystyle R} is the resistance at T {\displaystyle T} (in ohms), A {\displaystyle A} , B {\displaystyle B} , and C {\displaystyle C} are the Steinhart–Hart coefficients , which are characteristics specific to the bulk semiconductor material over a given temperature range of interest.
The 3ω-method can be accomplished by depositing a thin metal structure (generally a wire or a film) onto the sample to function as a resistive heater and a resistance temperature detector (RTD). The heater is driven with AC current at frequency ω, which induces periodic joule heating at frequency 2ω (since P = I 2 R {\displaystyle P=I^{2}R ...
Also called chordal or DC resistance This corresponds to the usual definition of resistance; the voltage divided by the current R s t a t i c = V I. {\displaystyle R_{\mathrm {static} }={V \over I}.} It is the slope of the line (chord) from the origin through the point on the curve. Static resistance determines the power dissipation in an electrical component. Points on the current–voltage ...
Maximum temperature drop from junction to ambient = (+). We use the general principle that the temperature drop Δ T {\displaystyle \Delta T} across a given absolute thermal resistance R θ {\displaystyle R_{\theta }} with a given heat flow Q ˙ {\displaystyle {\dot {Q}}} through it is:
Four-point measurement of resistance between voltage sense connections 2 and 3. Current is supplied via force connections 1 and 4. In electrical engineering, four-terminal sensing (4T sensing), 4-wire sensing, or 4-point probes method is an electrical impedance measuring technique that uses separate pairs of current-carrying and voltage-sensing electrodes to make more accurate measurements ...
The effective temperature coefficient varies with temperature and purity level of the material. The 20 °C value is only an approximation when used at other temperatures. For example, the coefficient becomes lower at higher temperatures for copper, and the value 0.00427 is commonly specified at 0 °C. [53]