دانلود مقاله تحقیقی لاتین با موضوع جریان متناوب (alternating current (AC
نوع فایل : Word
تعداد صفحات : 7
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City lights viewed in a motion blurred exposure. The AC blinking causes the lines to be dotted rather than continuous.
An alternating current (AC) is an electrical current whose magnitude and direction vary cyclically, as opposed to direct current, whose direction remains constant. The usual waveform of an AC power circuit is a sine wave, as this results in the most efficient transmission of energy. However in certain applications different waveforms are used, such as triangular or square waves.
Used generically, AC refers to the form in which electricity is delivered to businesses and residences. However, audio and radio signals carried on electrical wire are also examples of alternating current. In these applications, an important goal is often the recovery of information encoded (or modulated) onto the AC signal
History
William Stanley, Jr. designed one of the first practical devices to transfer AC power efficiently between isolated circuits. Using pairs of coils wound on a common iron core, his design, called an induction coil, was an early precursor of the modern transformer. The system used today was devised in the late nineteenth century, largely by Nikola Tesla. Contributions were also made by George Westinghouse, Lucien Gaulard, John Dixon Gibbs, Carl Wilhelm Siemens and Oliver Shallenger. AC systems overcame the limitations of the direct current system used by Thomas Edison to distribute electricity efficiently over long distances