AC abbreviation, alternating current, electric charge movement which is reversing regularly. It begins, say, from zero, increases to a limit, decreases to zero, reverses, in the reverse direction achieves a limit, goes back to the original value, and continues this sequence for ever again. The time difference between a given value and the consecutive cycles is known as the time interval, the number of cycles or intervals per second is the frequency, the maximum value is the amplitude of the alternating current, in all directions.
Frequency components, such as 50 and 60 cycles per second (hertz), are used for domestic and commercial power, but alternating frequency currents about 100,000,000 cycles per second (100 MHz) are used in broadcasting, and those of several thousand megahertz are used in radar or microwave. Cell phones run at nearly 1,000 megahertz (1GHz) frequencies.
An electrical motor produces an alternating current. An electric generator has a magnet and a wire loop spinning in the magnet sector. The wire spinning through the magnetic field creates a force pushing electric charges through the wire by increasing the power of the magnetic field through the cable. Initially, the force induces an electric current through the wire in one direction. As the coil rotates by 180 degrees, so the force reverses in order to send an electrical pressure to the wire in the opposite way. The trajectory and hence the current change each time the loop rotates around 180 degrees. The alternating current is given by the changing direction of the force at every 180 °. In addition to providing the electric generator magnet and cable, the slip rings ensure that the ends of the cable are still attached to the same side of the electric circuit. This means that every half rotation of the wire changes the direction of the current.