ELECTRICAL ENCYCLOPEDIA

AC circuit analysis http://fourier.eng.hmc.edu   Operations on sinusoidal variables based on the trigonometric identities are in general lengthy and tedious. The phasor method can convert such sinusoidal variables to vectors in complex plane and thereby simplify the operations. A sinusoidal time function can be considered as the real (or imaginary) part of a rotating vector in the complex plane. If two sinusoidal functions have the same frequency , i.e., they are rotating at the same rate, their relative positions with respect to each other are fixed independent of . Therefore the vectors can be considered as static instead of rotating if observed from a reference frame rotating at the same frequency as the vectors. An operation of two sinusoids can be carried out on their phasors, and the resulting phasor can then be converted back to a sinusoidal time function by taking the real part of the phasor now assumed to be rotating. All about AC circuits http://www.allaboutcircuits.com ...

Phasor Diagrams http://hyperphysics.phy-astr.gsu.edu   It is sometimes helpful to treat the phase as if it defined a vector in a plane. The usual reference for zero phase is taken to be the positive x-axis and is associated with the resistor since the voltage and current associated with the resistor are in phase. The length of the phasor is proportional to the magnitude of the quantity represented, and its angle represents its phase relative to that of the current through the resistor. The phasor diagram for the RLC series circuit shows the main features. Electrical Phasor Diagrams http://en.wikipedia.org   In physics and engineering, a phase vector, or phasor, is a representation of a sine wave whose amplitude (A), phase (θ), and angular frequency (ω) are time-invariant. It is a subset of a more general concept called analytic representation. Phasors reduce the dependencies on these parameters to three independent factors, thereby simplifying certain kinds of calculations. I...

Y-Δ transform http://en.wikipedia.org   The transformation is used to establish equivalence for networks with three terminals. Where three elements terminate at a common node and none are sources, the node is eliminated by transforming the impedances. For equivalence, the impedance between any pair of terminals must be the same for both networks. The equations given here are valid for complex as well as real impedances. Delta and Wye Worksheet http://openbookproject.net/   This worksheet and all related files are licensed under the Creative Commons Attribution License, version 1.0. To view a copy of this license, visit http://creativecommons.org/licenses/by/1.0/, or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA. The terms and conditions of this license allow for free copying, distribution, and/or modification of all licensed works by the general public. Methods of Analysis http://webtools.delmarlearning.com  ...