January 26, 2014

Difference between AC and DC

Electricity flows in two ways; either in alternating current (AC) or in direct current (DC). Electricity or 'current' is nothing more than moving electrons along a conductor, like a wire, that have been harnessed for energy. Therefore, the difference between AC and DC has to do with 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 "forwards" and then going "backwards."

Comparison chart

Alternating Current
Direct Current
Amount of energy that can be carried
Safe to transfer over longer city distances and can provide more power.
Voltage of DC cannot travel very far until it begins to lose energy.
Cause of the direction of flow of electrons
Rotating magnet along the wire.
Steady magnetism along the wire.
The frequency of alternating current is 50Hz or 60Hz depending upon the country.
The frequency of direct current is zero.
It reverses its direction while flowing in a circuit.
It flows in one direction in the circuit.
It is the current of magnitude varying with time
It is the current of constant magnitude.
Flow of Electrons
Electrons keep switching directions - forward and backward.
Electrons move steadily in one direction or 'forward'.
Obtained from
A.C Generator and mains.
Cell or Battery.
Passive Parameters
Resistance only
Power Factor
Lies between 0 & 1.
it is always 1.
Sinusoidal, Trapezoidal, Triangular, Square.
Pure and pulsating.


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