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  2. Power factor - Wikipedia

    en.wikipedia.org/wiki/Power_factor

    The power factor in a single-phase circuit (or balanced three-phase circuit) can be measured with the wattmeter-ammeter-voltmeter method, where the power in watts is divided by the product of measured voltage and current. The power factor of a balanced polyphase circuit is the same as that of any phase. The power factor of an unbalanced ...

  3. Leading and lagging current - Wikipedia

    en.wikipedia.org/wiki/Leading_and_Lagging_Current

    Angle notation can easily describe leading and lagging current: . [1] In this equation, the value of theta is the important factor for leading and lagging current. As mentioned in the introduction above, leading or lagging current represents a time shift between the current and voltage sine curves, which is represented by the angle by which the curve is ahead or behind of where it would be ...

  4. Taft equation - Wikipedia

    en.wikipedia.org/wiki/Taft_equation

    where ⁡ is the ratio of the rate of the substituted reaction compared to the reference reaction, ρ* is the sensitivity factor for the reaction to polar effects, σ* is the polar substituent constant that describes the field and inductive effects of the substituent, δ is the sensitivity factor for the reaction to steric effects, and E s is ...

  5. Thermoelectric materials - Wikipedia

    en.wikipedia.org/wiki/Thermoelectric_materials

    The efficiency of a thermoelectric device for electricity generation is given by , defined as =.. The maximum efficiency of a thermoelectric device is typically described in terms of its device figure of merit where the maximum device efficiency is approximately given by [7] = + ¯ + ¯ +, where is the fixed temperature at the hot junction, is the fixed temperature at the surface being cooled ...

  6. Peukert's law - Wikipedia

    en.wikipedia.org/wiki/Peukert's_law

    It is a common misunderstanding [2] that the energy not delivered by the battery due to Peukert's law is "lost" (as heat for example). In fact, once the load is removed, the battery voltage will recover, [3] and more energy can again be drawn out of the battery.

  7. Exchange interaction - Wikipedia

    en.wikipedia.org/wiki/Exchange_interaction

    In chemistry and physics, the exchange interaction is a quantum mechanical constraint on the states of indistinguishable particles.While sometimes called an exchange force, or, in the case of fermions, Pauli repulsion, its consequences cannot always be predicted based on classical ideas of force. [1]

  8. Thermoelectric effect - Wikipedia

    en.wikipedia.org/wiki/Thermoelectric_effect

    The Seebeck effect, Peltier effect, and Thomson effect can be gathered together in a consistent and rigorous way, described here; this also includes the effects of Joule heating and ordinary heat conduction. As stated above, the Seebeck effect generates an electromotive force, leading to the current equation [11]

  9. Reduction potential - Wikipedia

    en.wikipedia.org/wiki/Reduction_potential

    In aqueous solutions, redox potential is a measure of the tendency of the solution to either gain or lose electrons in a reaction. A solution with a higher (more positive) reduction potential than some other molecule will have a tendency to gain electrons from this molecule (i.e. to be reduced by oxidizing this other molecule) and a solution with a lower (more negative) reduction potential ...