CURRENT (AC) BASIC

==Alternating Current== In alternating current (AC), the flow of electric charge periodically reverses direction, whereas in direct current (DC, also dc), the flow of electric charge is only in one direction. The abbreviations AC and DC are often used to mean simply alternating and direct, as when they modify current or voltage. [image:http://i.imgur.com/buECwX1.jpg] Charges (electrons) must always be flowing to have a current. However, the flow of charges does not always have to be in one direction. In alternating current, the charges move in one direction for a very short time, and then they reverse direction. This happens over and over again. [image:http://i.imgur.com/SNi5bH9.gif] Low frequency and high frequency wavelengths. Scientists describe the cycle of switching directions as the frequency. Frequency is measured in Hertz (Hz). Currents that cycle more often during a specific amount of time are said to have a higher frequency. AC power cycles 50 times per second in New Zealand. [image:http://i.imgur.com/yykTb0s.gif] AC Electricity is used to transmit electrical energy across long distances to your house or school. The power sockets that you plug your devices into supply AC electricity. AC has the advantage that the '''voltage''' can be easily changed (stepped up or stepped down) using a '''TRANSFORMER'''. [image:http://i.imgur.com/TfhQ0CM.jpg]