> Having AC power allows all kinds of cool things! Did you know that your common household 120v feed is simply a single phase being split into two 120v 'legs'. Both 120 degrees out of phase. So if you remember elementary school math the abs() of phase A at its peak of +120 and phase B at it's valley of -120 = 240.
The two legs are 180 degrees "out of phase" (that is to say one is simply the negative to the other). The peaks on each are +/- 170 volts, with a total peak across both of 340 volts. But we talk about AC in terms of RMS voltage, which is the DC-equivalent voltage that would perform the same work into a resistor, which is a factor of sqrt(2) for a sine wave, or "120/240 volts".
The two legs are 180 degrees "out of phase" (that is to say one is simply the negative to the other). The peaks on each are +/- 170 volts, with a total peak across both of 340 volts. But we talk about AC in terms of RMS voltage, which is the DC-equivalent voltage that would perform the same work into a resistor, which is a factor of sqrt(2) for a sine wave, or "120/240 volts".