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Reciprocity of electrical networks is a special case of Lorentz reciprocity, but it can also be proven more directly from network theorems. This proof shows reciprocity for a two-node network in terms of its admittance matrix, and then shows reciprocity for a network with an arbitrary number of nodes by an induction argument.
NECA currently has 119 local chapters across the United States, with a national headquarters in Washington, D.C. At the local level, each NECA chapter is an independently chartered organization with the autonomy to elect officers, determine priorities, set member dues and service charges, and help negotiate labor agreements with their local International Brotherhood of Electrical Workers (IBEW ...
Reciprocity in linear systems is the principle that a response Rab, measured at a location (and direction if applicable) a, when the system has an excitation signal applied at a location (and direction if applicable) b, is exactly equal to Rba which is the response at location b, when that same excitation is applied at a. This applies for all ...
In modern apprenticeship systems, a journeyman has a trades certificate to show the required completion of an apprenticeship. In many countries, it is the highest formal rank, as that of master has been eliminated, and they may perform all tasks of the trade in the area certified as well as supervise apprentices and become self-employed.
Forms of the reciprocity theorems are used in many electromagnetic applications, such as analyzing electrical networks and antenna systems. [1] For example, reciprocity implies that antennas work equally well as transmitters or receivers, and specifically that an antenna's radiation and receiving patterns are identical.
Electricians were originally people who demonstrated or studied the principles of electricity, often electrostatic generators of one form or another. [2]In the United States, electricians are divided into two primary categories: lineperson, who work on electric utility company distribution systems at higher voltages, and wiremen, who work with the lower voltages utilized inside buildings.
The National Electrical Code, 2008 edition. The National Electrical Code (NEC), or NFPA 70, is a regionally adoptable standard for the safe installation of electrical wiring and equipment in the United States. It is part of the National Fire Code series published by the National Fire Protection Association (NFPA), a private trade association. [1]
The Electrical Workers: A History of Labor at General Electric and Westinghouse, 1923-60, University of Illinois Press, 1983, hardcover, ISBN 0-252-01031-0; paperback reprint ISBN 0-252-01438-3; Sears, John Bennett, Generation of Resistance: The Electrical Unions and the Cold War, Infinity Publishing, 2008, paperback, ISBN 0-7414-4868-8