What does the vertical axis on a voltage sine wave represent?

The vertical axis on a voltage sine wave represents voltage. In a sine wave graph, the vertical axis is used to indicate the amplitude of the voltage at different points in time, which is essential for understanding how voltage fluctuates in an AC (alternating current) circuit. This fluctuation is key in applications such as power distribution and electrical engineering, as it shows the variation of voltage over a cycle. Each point on the vertical axis corresponds to a specific voltage value at the corresponding time along the horizontal axis, which tracks the progression of the waveform over time. This relationship helps engineers and electricians analyze and work with AC signals effectively.