Like a river current is the flow of water molecules, electrical current is the flow of charged particles i.e electrons.
The SI unit for measuring an electric current is the ampere(the flow of electric charge across a surface at the rate of one columb per second). One ampere of current represents one coulomb of electrical charge (6.24 x 1018 charge carriers) moving past a specific point in one second.
Electricity flows in two ways: either in an alternating current (AC) or in a direct current (DC).
The difference between AC and DC lies in the direction in which the electrons flow. In DC, the electrons flow steadily in a single direction, or "forward." In AC, electrons keep switching directions, sometimes going "forward" and then going "backward."
Alternating current is the best way to transmit electricity over large distances.
Current per unit cross-sectional area is known as current density. It is expressed in amperes per square meter, amperes per square centimeter, or amperes per square millimeter. Current density can also be expressed in amperes per circular mil. In general, the greater the current in a conductor, the higher the current density. However, in some situations, current density varies in different parts of an electrical conductor. A classic example is the so called skin effect, in which current density is high near the outer surface of a conductor, and low near the center. This effect occurs with alternating currents at high frequencies.
The SI unit for measuring an electric current is the ampere(the flow of electric charge across a surface at the rate of one columb per second). One ampere of current represents one coulomb of electrical charge (6.24 x 1018 charge carriers) moving past a specific point in one second.
Electricity flows in two ways: either in an alternating current (AC) or in a direct current (DC).The difference between AC and DC lies in the direction in which the electrons flow. In DC, the electrons flow steadily in a single direction, or "forward." In AC, electrons keep switching directions, sometimes going "forward" and then going "backward."
Alternating current is the best way to transmit electricity over large distances.
| Cause of the direction of flow of electrons | Rotating magnet along the wire. | Steady magnetism along the wire. |
|---|
Current per unit cross-sectional area is known as current density. It is expressed in amperes per square meter, amperes per square centimeter, or amperes per square millimeter. Current density can also be expressed in amperes per circular mil. In general, the greater the current in a conductor, the higher the current density. However, in some situations, current density varies in different parts of an electrical conductor. A classic example is the so called skin effect, in which current density is high near the outer surface of a conductor, and low near the center. This effect occurs with alternating currents at high frequencies.
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