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'''Alternating current''' (commonly abbreviated '''AC''') is a type of [[electrical current]], the direction of which is reversed at regular intervals or cycles. In the United States, the standard is 120 reversals or 60 cycles per second. Electricity transmission networks use AC because [[voltage]] can be controlled with relative ease.<ref>http://www1.eere.energy.gov/solar/solar_glossary.html</ref>

'''Alternating current''' (commonly abbreviated '''AC''') is a type of [[electrical current]], the direction of which is reversed at regular intervals or cycles. That is, it has a non-zero [[frequency]], as opposed to direct current ([[DC]]), which has a zero frequency.  In the United States, the standard is 120 reversals or 60 cycles per second. Electricity transmission networks use AC because [[voltage]] can be controlled with relative ease.<ref>http://www1.eere.energy.gov/solar/solar_glossary.html</ref>

== References ==

== References ==