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  2. Ohm's law - Wikipedia

    en.wikipedia.org/wiki/Ohm's_law

    where E is the electric field vector with units of volts per meter (analogous to V of Ohm's law which has units of volts), J is the current density vector with units of amperes per unit area (analogous to I of Ohm's law which has units of amperes), and ρ "rho" is the resistivity with units of ohm·meters (analogous to R of Ohm's law which has ...

  3. Electrical resistivity and conductivity - Wikipedia

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

    Electrical conductivity of water samples is used as an indicator of how salt-free, ion-free, or impurity-free the sample is; the purer the water, the lower the conductivity (the higher the resistivity). Conductivity measurements in water are often reported as specific conductance, relative to the conductivity of pure water at 25 °C.

  4. Electric current - Wikipedia

    en.wikipedia.org/wiki/Electric_current

    For negative charges, the sign of the current density is opposite to the velocity of the charges. [2]: 749 In SI units, current density (symbol: j) is expressed in the SI base units of amperes per square metre. [4]: 22 In linear materials such as metals, and under low frequencies, the current density across the conductor surface is uniform.

  5. Current density - Wikipedia

    en.wikipedia.org/wiki/Current_density

    In electromagnetism, current density is the amount of charge per unit time that flows through a unit area of a chosen cross section. [1] The current density vector is defined as a vector whose magnitude is the electric current per cross-sectional area at a given point in space, its direction being that of the motion of the positive charges at this point.

  6. List of physical quantities - Wikipedia

    en.wikipedia.org/wiki/List_of_physical_quantities

    Electric charge density: ρ Q: Electric charge per unit volume C/m 3: L −3 T I: intensive Electrical conductance: G: Measure for how easily current flows through a material siemens (S = Ω −1) L −2 M −1 T 3 I 2: scalar Electrical conductivity: σ: Measure of a material's ability to conduct an electric current S/m L −3 M −1 T 3 I 2 ...

  7. 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 ...

  8. International System of Electrical and Magnetic Units

    en.wikipedia.org/wiki/International_System_of...

    The unvarying current which, when passed through a solution of silver nitrate in water, deposits silver at the rate of 0.001 118 00 grams per second The current produced in a conductor with a 1 ohm resistance when there is a potential difference of 1 volt between its ends 0.1 CGS-EMU units of electric current international ohm

  9. Contact resistance - Wikipedia

    en.wikipedia.org/wiki/Contact_resistance

    The units of specific contact resistivity are typically therefore in ohm-square metre, or Ω⋅m 2. When the current is a linear function of the voltage, the device is said to have ohmic contacts. Inductive and capacitive methods could be used in principle to measure an intrinsic impedance without the