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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 ...
Direct current may be converted into alternating current via an inverter. Direct current has many uses, from the charging of batteries to large power supplies for electronic systems, motors, and more. Very large quantities of electrical energy provided via direct-current are used in smelting of aluminum and other electrochemical processes.
Alternating current can also be converted to direct current through use of a rectifier. Direct current may flow in a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams. An old name for direct current was galvanic current. [17]
Over 98% of the current will flow within a layer 4 times the skin depth from the surface. This behavior is distinct from that of direct current which usually will be distributed evenly over the cross-section of the wire. An alternating current may also be induced in a conductor due to an alternating magnetic field according to the law of induction.
Pulsating direct current has an average value equal to a constant (DC) along with a time-dependent pulsating component added to it, while the average value of alternating current is zero in steady state (or a constant if it has a DC offset, value of which will then be equal to that offset).
In a simple alternating current (AC) circuit consisting of a source and a linear time-invariant load, both the current and voltage are sinusoidal at the same frequency. [3] If the load is purely resistive, the two quantities reverse their polarity at the same time. Hence, the instantaneous power, given by the product of voltage and current, is ...
Materials and components that obey Ohm's law are described as "ohmic" [30] which means they produce the same value for resistance (R = V/I) regardless of the value of V or I which is applied and whether the applied voltage or current is DC (direct current) of either positive or negative polarity or AC (alternating current).
A power converter is an electrical device for converting electrical energy between alternating current (AC) and direct current (DC). It can also change the voltage or frequency of the current. Power converters include simple devices such as transformers, and more complex ones like resonant converters.