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  2. Electrical resistivity and conductivity - Wikipedia

    en.wikipedia.org/wiki/Electrical_resistivity_and...

    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.

  3. Resistance thermometer - Wikipedia

    en.wikipedia.org/wiki/Resistance_thermometer

    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 ...

  4. Joule heating - Wikipedia

    en.wikipedia.org/wiki/Joule_heating

    Joule heating (also known as resistive, resistance, or Ohmic heating) is the process by which the passage of an electric current through a conductor produces heat.. Joule's first law (also just Joule's law), also known in countries of the former USSR as the Joule–Lenz law, [1] states that the power of heating generated by an electrical conductor equals the product of its resistance and the ...

  5. Electrical resistance and conductance - Wikipedia

    en.wikipedia.org/wiki/Electrical_resistance_and...

    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 ...

  6. Thermal conductivity and resistivity - Wikipedia

    en.wikipedia.org/wiki/Thermal_conductivity_and...

    Temperature dependence of the mean free path has an exponential form /. The presence of the reciprocal lattice wave vector implies a net phonon backscattering and a resistance to phonon and thermal transport resulting finite λ L, [50] as it means that momentum is not conserved. Only momentum non-conserving processes can cause thermal resistance.

  7. Skin effect - Wikipedia

    en.wikipedia.org/wiki/Skin_effect

    Skin effect reduces the effective cross-section of the conductor and thus increases its effective resistance. At 60 Hz in copper, skin depth is about 8.5 mm. At high frequencies, skin depth becomes much smaller. Increased AC resistance caused by skin effect can be mitigated by using a specialized multistrand wire called litz wire. Because the ...

  8. Thermal conductance and resistance - Wikipedia

    en.wikipedia.org/wiki/Thermal_conductance_and...

    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.

  9. Neher–McGrath method - Wikipedia

    en.wikipedia.org/wiki/Neher–McGrath_method

    For wire sizes smaller than AWG No. 2 (33.6 mm 2, 0.0521 sq in), this term is also generally regarded as insignificant. R c , a {\textstyle R_{c,a}} is the effective thermal resistance between the conductor and the ambient conditions, which can require significant empirical or theoretical effort to estimate.