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Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams.
The war of the currents was a series of events surrounding the introduction of competing electric power transmission systems in the late 1880s and early 1890s. It grew out of two lighting systems developed in the late 1870s and early 1880s; arc lamp street lighting running on high-voltage alternating current (AC), and large-scale low-voltage direct current (DC) indoor incandescent lighting ...
Invented by Peter Cooper Hewitt in 1902, it was used to convert alternating current (AC) into direct current (DC). From the 1920s on, research continued on applying thyratrons and grid-controlled mercury arc valves to power transmission.
Invented by Peter Cooper Hewitt in 1902, it was used to convert alternating current (AC) into direct current (DC). From the 1920s on, research continued on applying thyratrons and grid-controlled mercury arc valves to power transmission.
"Dynamo Electric Machine" (end view, partly section, U.S. patent 284,110) A dynamo is an electrical generator that creates direct current using a commutator.Dynamos were the first electrical generators capable of delivering power for industry, and the foundation upon which many other later electric-power conversion devices were based, including the electric motor, the alternating-current ...
The abbreviations AC and DC are often used to mean simply alternating and direct, respectively, as when they modify current or voltage. [ 1 ] [ 2 ] The usual waveform of alternating current in most electric power circuits is a sine wave , whose positive half-period corresponds with positive direction of the current and vice versa (the full ...
John Gray also invented a belt machine about 1890. [4] Another more complicated belt machine was invented in 1903 by Juan Burboa. [ 1 ] [ 5 ] A more immediate inspiration for Van de Graaff was a generator W. F. G. Swann was developing in the 1920s in which charge was transported to an electrode by falling metal balls, thus returning to the ...
In the late 1870s to early 1880s, the spread of arc lighting, a type of outdoor street lighting that required high voltages in the range of 3000–6000 volts, was followed by one story after another in newspapers about how the high voltages used were killing people, usually unwary linemen; it was a strange new phenomenon that seemed to instantaneously strike a victim dead without leaving a ...