The phasor diagram (left) and sine wave graph (right) further illustrate the link between the current and voltage. A full rotation of the arrows in the phasor diagram represents one cycle. The arrow points straight up along the y-axis when the current or voltage has reached its maximum value, and they are equal to zero when aligned to the x-axis (horizontal axis).
The scenarios pictured here are idealized, and the relationships between current and voltage in these components may vary slightly in the real world. The alternating currents that run through our homes go through 60 cycles per second (measured in Hertz) in the United States. European homes clock in at 50 Hertz. Although it’s too quick for our eyes to notice, the alternating current in our buildings makes the lightbulbs we use flash constantly. A phenomenon you might have noticed if you’ve ever tried to shoot a slow-motion video.