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In the power systems analysis field of electrical engineering, a per-unit system is the expression of system quantities as fractions of a defined base unit quantity. . Calculations are simplified because quantities expressed as per-unit do not change when they are referred from one side of a transformer to t
Continuous charge distribution. The volume charge density ρ is the amount of charge per unit volume (cube), surface charge density σ is amount per unit surface area (circle) with outward unit normal n̂, d is the dipole moment between two point charges, the volume density of these is the polarization density P.
The volt-ampere (SI symbol: VA, [1] sometimes V⋅A or V A) is the unit of measurement for apparent power in an electrical circuit. It is the product of the root mean square voltage (in volts) and the root mean square current (in amperes). [2] Volt-amperes are usually used for analyzing alternating current (AC) circuits.
In electrical engineering, the power factor of an AC power system is defined as the ratio of the real power absorbed by the load to the apparent power flowing in the circuit. . Real power is the average of the instantaneous product of voltage and current and represents the capacity of the electricity for performing
In electrical engineering, susceptance (B) is the imaginary part of admittance (Y = G + jB), where the real part is conductance (G). The reciprocal of admittance is impedance ( Z = R + jX ), where the imaginary part is reactance ( X ) and the real part is resistance ( R ).
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. A three-phase system may be arranged in delta (∆) or star (Y) (also denoted as wye in some areas, as symbolically it is similar to the letter 'Y').
That β does indeed represent phase can be seen from Euler's formula: e i θ = cos θ + i sin θ {\displaystyle e^{i\theta }=\cos {\theta }+i\sin {\theta }\ } which is a sinusoid which varies in phase as θ varies but does not vary in amplitude because
ε 0 is the permittivity of free space; E is the electric field intensity; and; P is the polarization of the medium. Differentiating this equation with respect to time defines the displacement current density, which therefore has two components in a dielectric: [1] (see also the "displacement current" section of the article "current density")