I wrote:
"RMS is the effective value, not the average value of an a-c ampere.

Steve Nosko responded:
"I will differ here. The RMS value is more appropriately described as
the power producing value of ANY wave form.."

A periodic function is not necessarily a sine wave but when I look up
alternating current in my dictionary, I find the diagram of a sine wave
and it is tagged: "alternating current".

By fourier series, any complex waveform may be resolved into a
fundamental plus a finite number of terms involving its harmonics.

My electronics dictionary says:
"The rms value of a periodic quantity is equal to the square root of the
average of the squares of the instantaneous values of the quantity taken
throughout one period. If that quantity is a sinewave, its rms amplitude
is 0.707 of its peak value."

My dictionary also says:
"Effective current---That value of alternating current which will give
the same heating effect as the corresponding value of direct current.
For sine-wave alternating currents, the effective value is 0.707 times
the peak value."

The average value for one alternation of a sine wave is 2/pi or 0.637
times the maximum value.

I make lots of mistakes, but fortunately, I don`t think I made any of
consequence in this thread. I probably didn`t go into enough detail, but
I was just an engineer, not a professor.

Best regards, Richard Harrison, KB5WZI