NSM wrote:

"Choreboy" wrote in message
...

To call a waveform an AC sine wave implies that there is no DC, but this
thread is the first time I've read the claim that all sine waves are AC
sine waves.

FWIW, most waveforms can be created as the sum of sine waves. I wrote an
interesting computer demo once that showed how a sine and it's harmonics
could be added graphically to form a better and better approximation of a
square wave, running through what looked like Butterworth etc. responses.

N

With high frequency and amplitude, a sine wave could be very steep at 0
and 180 degrees. It could also turn sharply at 90 and 270, like the
corner of a square wave. You would need low frequency and amplitude for
a sine wave to approximate the flat peaks of a square wave.

That part is simple enough for me, but I don't understand harmonics. If
you overdrive an amplifier with a sine wave, the output will resemble a
square wave. I know the output can be broken down into the input
frequency and its odd multiples. I'll have to accept it on faith.