What is sinusoidal AC voltage (i.e. voltage with a sine-waveform)?
The voltage waveform of 120 VAC, 60 Hz mains / utility power is like a sine wave. In a voltage with a sine wave-form, the instantaneous value and polarity of the voltage varies with respect to time and the wave-form is like a sine wave. In one cycle, it slowly rises in the positive direction from 0 V to a peak positive value + Vpeak = 170 V, slowly drops to 0 V, changes the polarity to negative direction and slowly increases in the negative direction to a peak negative value – Vpeak =170 V and then slowly drops back to 0 V. There are 60 such cycles in 1 sec.
