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  2. Alternating current - Wikipedia

    en.wikipedia.org/wiki/Alternating_current

    Alternating current (AC) is an electric current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction.

  3. Skin effect - Wikipedia

    en.wikipedia.org/wiki/Skin_effect

    Distribution of current flow in a cylindrical conductor, shown in cross section. For alternating current, current density decreases exponentially from the surface towards the inside. Skin depth, δ, is defined as the depth where the current density is just 1/e (about 37%) of the value at the surface; it depends on the frequency of the current ...

  4. Electric current - Wikipedia

    en.wikipedia.org/wiki/Electric_current

    In alternating current (AC) systems, the movement of electric charge periodically reverses direction. AC is the form of electric power most commonly delivered to businesses and residences. The usual waveform of an AC power circuit is a sine wave , though certain applications use alternative waveforms, such as triangular or square waves .

  5. AC power - Wikipedia

    en.wikipedia.org/wiki/AC_power

    In a simple alternating current (AC) circuit consisting of a source and a linear time-invariant load, both the current and voltage are sinusoidal at the same frequency. [3] If the load is purely resistive, the two quantities reverse their polarity at the same time. Hence, the instantaneous power, given by the product of voltage and current, is ...

  6. 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 ...

  7. Faraday's law of induction - Wikipedia

    en.wikipedia.org/wiki/Faraday's_law_of_induction

    Alternating electric current flows through the solenoid on the left, producing a changing magnetic field. This field causes, by electromagnetic induction, an electric current to flow in the wire loop on the right. The most widespread version of Faraday's law states:

  8. Speed of electricity - Wikipedia

    en.wikipedia.org/wiki/Speed_of_electricity

    The drift velocity in a 2 mm diameter copper wire in 1 ampere current is approximately 8 cm per hour. AC voltages cause no net movement. The electrons oscillate back and forth in response to the alternating electric field, over a distance of a few micrometers – see example calculation.

  9. Current sensing - Wikipedia

    en.wikipedia.org/wiki/Current_sensing

    That the voltage drop across the shunt is proportional to its current flow, i.e. ohm's law, makes the low resistance current shunt a very popular choice for current measurement system with its low cost and high reliability. Both alternating currents (AC) and direct currents (DC) can be measured with the shunt resistor.