Changes

'''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>

'''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>