alternating current

GC: n

CT: AC is short for alternating current. This means that the direction of current flowing in a circuit is constantly being reversed back and forth. This is done with any type of AC current/voltage source.
The electrical current in your house is alternating current. This comes from power plants that are operated by the electric company. Those big wires you see stretching across the countryside are carrying AC current from the power plants to the loads, which are in our homes and businesses. The direction of current is switching back and forth 60 times each second.

S: (last access: 18 February 2015)

N: 1. alternating (adj): 1550s, present participle adjective from alternate (v.). Alternating current is recorded from 1839.
current (n): late 14c., from Middle French corant (Modern French courant), from Old French corant. Applied 1747 to the flow of electrical force.
AC/DC (adj): electronics abbreviation of alternating current/direct current, by 1898.
2. Most students of electricity begin their study with what is known as direct current (DC), which is electricity flowing in a constant direction, and/or possessing a voltage with constant polarity. DC is the kind of electricity made by a battery (with definite positive and negative terminals), or the kind of charge generated by rubbing certain types of materials against each other.
As useful and as easy to understand as DC is, it is not the only “kind” of electricity in use. Certain sources of electricity (most notably, rotary electro-mechanical generators) naturally produce voltages alternating in polarity, reversing positive and negative over time. Either as a voltage switching polarity or as a current switching direction back and forth, this “kind” of electricity is known as Alternating Current (AC).
3. Unless distinctly specified otherwise, the term alternating current refers to a current which reverses at regularly recurring intervals of time and which has alternately positive and negative values.
4. Cultural Interrelation. Tesla vs Edison: the war of currents. The War of the Currents was won by AC, which has been the platform for electrical transmission across the world since that time.

S: 1. OED – (last access: 18 February 2015). 2. (last access: 18 February 2015). 3. TERMIUMPLUS. 4. (last access: 31 March 2015).



CR: direct current, electrical energy, electric current.