Alternating and Direct Current
At the time, there were two currents vying for the world power source. Alternating Current (AC), and Direct Current (DC). In the end, it would become a fierce battle between Tesla's AC system, and Edison's DC system.
AC is considered a superior source of energy. It is easier to transmit over long distances with less energy loss. It uses thinner wires and higher voltages. AC allows transformation to higher voltage at lower currents to deliver the same power. Voltage is then transformed back down to house voltage (120 Vac) at higher currents to deliver the required power. With DC, transformation is not possible; the generated voltage must be the delivered voltage. To deliver the required power, higher transmitted currents are necessary resulting in far greater power line losses; meaning less energy delivered to the end customer. AC is used for powering homes and buildings.
AC is considered a superior source of energy. It is easier to transmit over long distances with less energy loss. It uses thinner wires and higher voltages. AC allows transformation to higher voltage at lower currents to deliver the same power. Voltage is then transformed back down to house voltage (120 Vac) at higher currents to deliver the required power. With DC, transformation is not possible; the generated voltage must be the delivered voltage. To deliver the required power, higher transmitted currents are necessary resulting in far greater power line losses; meaning less energy delivered to the end customer. AC is used for powering homes and buildings.
Alternating Current
"Alternating current is current that changes direction cyclically, i.e., charges alternately flow in one direction, then in the other. The most common AC source is the commercial AC power system that supplies power to your home." (Page 38, Circuit Analysis: Theory and Practice). "Typical frequencies are 60 Hertz (Hz- cycle per second) in the US and 50Hz in other countries. It is accomplished by a rotating magnet across a coiled wire. AC would not be safe for household use at 34KVac; therefore power companies transform the voltage down to safe limits. 120 Vac in the US and 240 Vac in Europe." (Page 38, Circuit Analysis: Theory and Practice).
Direct Current
"Direct Current (DC) - Unidirectional current..." (Page 1073, Circuit Analysis: Theory and Practice) is a useful energy source for small distances, since it is subject to high energy losses. DC systems are less complicated and in today's world it is perfect to power small devices--cell phones, laptops, and music players.
"DC high power systems are accomplished in a similar manner to AC, but is rectified and filtered to direct current. In lower power systems, charged plates or cells are stacked to form a battery. Due to high losses over long distances, DC systems require a power plant approximately every square mile. The frequency of direct current in zero." (Page 1073, Circuit Analysis: Theory and Practice)
"DC high power systems are accomplished in a similar manner to AC, but is rectified and filtered to direct current. In lower power systems, charged plates or cells are stacked to form a battery. Due to high losses over long distances, DC systems require a power plant approximately every square mile. The frequency of direct current in zero." (Page 1073, Circuit Analysis: Theory and Practice)