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  2. Effective mass (solid-state physics) - Wikipedia

    en.wikipedia.org/wiki/Effective_mass_(solid...

    The effective mass is used in transport calculations, such as transport of electrons under the influence of fields or carrier gradients, but it also is used to calculate the carrier density and density of states in semiconductors. These masses are related but, as explained in the previous sections, are not the same because the weightings of ...

  3. 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.

  4. Skin effect - Wikipedia

    en.wikipedia.org/wiki/Skin_effect

    The effective resistance due to a current confined near the surface of a large conductor (much thicker than δ) can be solved as if the current flowed uniformly through a layer of thickness δ based on the DC resistivity of that material. The effective cross-sectional area is approximately equal to δ times the

  5. Charge carrier density - Wikipedia

    en.wikipedia.org/wiki/Charge_carrier_density

    The carrier density is usually obtained theoretically by integrating the density of states over the energy range of charge carriers in the material (e.g. integrating over the conduction band for electrons, integrating over the valence band for holes).

  6. Exchange current density - Wikipedia

    en.wikipedia.org/wiki/Exchange_current_density

    This ongoing current in both directions is called the exchange current density. When the potential is set more negative than the formal potential, the cathodic current is greater than the anodic current. Written as a reduction, cathodic current is positive. The net current density is the difference between the cathodic and anodic current density.

  7. Early effect - Wikipedia

    en.wikipedia.org/wiki/Early_effect

    Early, is the variation in the effective width of the base in a bipolar junction transistor (BJT) due to a variation in the applied base-to-collector voltage. A greater reverse bias across the collector–base junction, for example, increases the collector–base depletion width , thereby decreasing the width of the charge carrier portion of ...

  8. What Is the Marginal vs. Effective Tax Rate? - AOL

    www.aol.com/finance/marginal-vs-effective-tax...

    To calculate your effective tax rate, just divide your annual tax bill by your gross annual income. Then, multiply the quotient by 100. Effective Tax Rate Example. Consider the following example ...

  9. NTU method - Wikipedia

    en.wikipedia.org/wiki/NTU_Method

    The number of transfer units (NTU) method is used to calculate the rate of heat transfer in heat exchangers (especially parallel flow, counter current, and cross-flow exchangers) when there is insufficient information to calculate the log mean temperature difference (LMTD). Alternatively, this method is useful for determining the expected heat ...