An important point about terminology: In electrical circuits, current refers to the movement of charges, whereas voltage refers to the potential to create current. Current is analogous to the movement of water through a pipe. In this analogy, voltage is analogous to static water pressure. Voltage is therefore a form of potential energy, while current is the movement of charges through a conductor in response to that potential energy.
Although the abbreviation “AC” is literally derived from the term “alternating current” the abbreviation is also used to describe alternating charges (AC voltage) independent of current flow. Hence, for example, a vibrating string can set up an AC voltage across the terminal wires of a guitar pickup independent of how much current is flowing from that pickup to an amplifier.
AC voltage and current are often illustrated by a figure depicting a sine wave. The figure shown below shows two full cycles of AC voltage. As a comparison, the open G string on a guitar with standard tuning would generate 196 full AC cycles per second.