Just a few days ago was the vernal, or spring equinox. On that day in March, of course, the night is exactly as long as the day. Six months from now is the autumn equinox, when, once again, the night ...

According to textbooks, a sine wave is a wave whose form resembles a sine curve. Often in power electronics, we need a sine wave generator for some applications; a dc/ac power inverter, for example.