Understanding the Difference Between Alternating and Direct Current

Alternating current and direct current are the two main forms of charges powering our electric and electronic world. If you have heard the names AC and DC for the first time, then this Buzzle article will be very helpful in introducing the basic concepts about these power sources.

What is AC?
An alternating current can be defined as a flow of electric charge that changes its direction at regular intervals. The period/regular intervals at which an AC changes its direction is termed as its frequency (Hz). This current can be represented on a graph as a sinusoidal wave. Marine vehicles, spacecrafts, and military equipment sometimes use AC with a frequency of 400 Hz. However, for most of the time, including domestic use, the frequency of AC is fixed at 50 or 60 Hz. The households in the U.S. are supplied with 60 Hz AC, whereas the frequency of alternating current for domestic purposes is 50 Hz in European countries.

What is DC?
Direct current is a current (flow of electric charge or electrons) that flows only in one direction. If represented on a graph, DC can be plotted as a straight line as it does not change direction. Subsequently, there is no frequency associated with a DC. If you are a student, the frequency of DC is normally asked as trivia. The fact is DC or direct current has zero frequency.

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