Amateur radio equipment normally derives its power from a variety of sources.For fixed stations the AC mains is readily available, is relatively cheap and is almost always used. It can be converted by transformers, rectifiers, smoothing circuits or switch mode (high frequency) circuits to a wide range of direct voltages and currents necessary for amateur equipment use. Batteries, both primary and secondary (accumulators) have always provided a convenient though relatively expensive source of power, especially for low powered or portable rigs, or test equipment. Discrete engine driven generators can give an output of DC or AC, but the most popular give an output of 240/230V AC at a nominal 50Hz, matching the domestic mains. Car alternators at present provide charging for a 12V accumulator, but there is no standard for electric cars.
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