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  2. AC power - Wikipedia

    en.wikipedia.org/wiki/AC_power

    [1]: 3 The portion of instantaneous power that results in no net transfer of energy but instead oscillates between the source and load in each cycle due to stored energy is known as instantaneous reactive power, and its amplitude is the absolute value of reactive power.

  3. Mathematics of three-phase electric power - Wikipedia

    en.wikipedia.org/wiki/Mathematics_of_three-phase...

    The plotted line represents the variation of instantaneous voltage (or current) with respect to time. This cycle repeats with a frequency that depends on the power system. In electrical engineering, three-phase electric power systems have at least three conductors carrying alternating voltages that are offset in time by one-third of the period ...

  4. Poynting vector - Wikipedia

    en.wikipedia.org/wiki/Poynting_vector

    The time-averaged power flow (according to the instantaneous Poynting vector averaged over a full cycle, for instance) is then given by the real part of S m. The imaginary part is usually ignored, however, it signifies "reactive power" such as the interference due to a standing wave or the near field of an antenna.

  5. Instantaneous phase and frequency - Wikipedia

    en.wikipedia.org/wiki/Instantaneous_phase_and...

    Instantaneous phase and frequency are important concepts in signal processing that occur in the context of the representation and analysis of time-varying functions. [1] The instantaneous phase (also known as local phase or simply phase ) of a complex-valued function s ( t ), is the real-valued function:

  6. Mean time between failures - Wikipedia

    en.wikipedia.org/wiki/Mean_time_between_failures

    For each observation, the "down time" is the instantaneous time it went down, which is after (i.e. greater than) the moment it went up, the "up time". The difference ("down time" minus "up time") is the amount of time it was operating between these two events.

  7. Shock response spectrum - Wikipedia

    en.wikipedia.org/wiki/Shock_response_spectrum

    Calculate (by direct time-domain simulation) the maximum instantaneous absolute acceleration experienced by the mass element of your SDOF at any time during (or after) exposure to the shock in question. This acceleration is a; Draw a dot at (f,a); Repeat steps 2–4 for many other values of f, and connect all the dots together into a smooth curve.

  8. Energy (signal processing) - Wikipedia

    en.wikipedia.org/wiki/Energy_(signal_processing)

    Similarly, the spectral energy density of signal x(t) is = | | where X(f) is the Fourier transform of x(t).. For example, if x(t) represents the magnitude of the electric field component (in volts per meter) of an optical signal propagating through free space, then the dimensions of X(f) would become volt·seconds per meter and () would represent the signal's spectral energy density (in volts ...

  9. Power (physics) - Wikipedia

    en.wikipedia.org/wiki/Power_(physics)

    Power in mechanical systems is the combination of forces and movement. In particular, power is the product of a force on an object and the object's velocity, or the product of a torque on a shaft and the shaft's angular velocity. Mechanical power is also described as the time derivative of work.