­Batteries, fuel cells and solar cells all produce something called direct current (DC). The positive and negative terminals of a battery are always, respectively, ... The big advantage that alternating current provides for the power grid is the fact that it is relatively easy to change the voltage of the power,
science.howstuffworks.com/electricity5.htm
War of Currents - Wikipedia, the free encyclopedia
In the "War of Currents" era (sometimes, "War of the Currents" or "Battle of Currents" ) in the late 1880s, George Westinghouse and Thomas Edison became adversaries due to Edison's promotion of ...
en.wikipedia.org/wiki/War_of_Currents
Alternating current - Wikipedia, the free encyclopedia
In alternating current ( AC, also ac ) the movement (or flow) of electric charge periodically reverses direction. An electric charge would for instance move forward, then backward, then forw...
en.wikipedia.org/wiki/Alternating_current
This is what is commonly know of as direct current or DC which is to say that there is no change in voltage over a period of time. This is not the kind of electricity found coming out of the sockets in your wall at home. ... So remember, alternating current means that both the voltage and the current are changing in time.
www.tonmeister.ca/main/textbook/node81.html
To find out more about alternating and direct current, what exactly an electric current is, and two ways that the currents can be produced, check out the interaction to the left and the pages that follow.
www.pbs.org/wgbh/amex/edison/sfeature/acdc.html
Alternating current (AC) electricity is the type of electricity commonly used in homes and businesses throughout the world. While direct current (DC) electricity flows in one direction through a wire, AC electricity alternates its direction in a back-and-forth motion.
www.school-for-champions.com/science/ac.htm
Direct vs Alternating Current - Examples ... Direct current moves charge ... Alternating current is always changing...
www.people.vcu.edu/~rgowdy/mod/087/xmp.htm www.people.vcu.edu/~rgowdy/mod/087/xmp.htm
Direct Current: Remains constant in time. ... Alternating Current: Reverses periodically.
www.people.vcu.edu/~rgowdy/mod/087/s.htm www.people.vcu.edu/~rgowdy/mod/087/s.htm
Of course, there are some kinds of loads that require current to flow in only one direction. In such cases, we often need to convert alternating current such as the power provided at your wall socket to direct current for use by the load.
www.play-hookey.com/ac_theory/