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The ampere is an SI base unit and electric current is a base quantity in the International System of Quantities (ISQ). [4]: 15 Electric current is also known as amperage and is measured using a device called an ammeter. [2]: 788 Electric currents create magnetic fields, which are used in motors, generators, inductors, and transformers.
The electric field was formally defined as the force exerted per unit charge, but the concept of potential allows for a more useful and equivalent definition: the electric field is the local gradient of the electric potential. Usually expressed in volts per metre, the vector direction of the field is the line of greatest slope of potential, and ...
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 electric current flows in a constant direction, distinguishing it from alternating current (AC). A term formerly used for this type of current was galvanic current. [1]
The product of the direct voltage and the direct current (mean values). DC ripple factor The ratio of half the difference between the maximum and minimum value of a pulsating direct current to the mean, value of this current. [m] direct AC/DC converter An electronic AC/DC converter without a DC or AC link. direct AC converter
A schematic representation of long distance electric power transmission. From left to right: G=generator, U=step-up transformer, V=voltage at beginning of transmission line, Pt=power entering transmission line, I=current in wires, R=total resistance in wires, Pw=power lost in transmission line, Pe=power reaching the end of the transmission line, D=step-down transformer, C=consumers.
Angle notation can easily describe leading and lagging current: . [1] In this equation, the value of theta is the important factor for leading and lagging current. As mentioned in the introduction above, leading or lagging current represents a time shift between the current and voltage sine curves, which is represented by the angle by which the curve is ahead or behind of where it would be ...
Today the vast majority of publications no longer refer to electricity as meaning electric charge. Instead they speak of electricity as electromagnetic energy. The definition has drifted even further, and many authors now use the word electricity to mean electric current , energy flow , electrical potential , or electric force. Others refer to ...
Current (hydrology), currents in rivers and streams; Convection current, flow caused by unstable density variation due to temperature differences; Current (mathematics), geometrical current in differential topology; Conserved current, a field associated to a symmetry in field theory; Electric current, a flow of electric charge through a medium