Oh my goodness! The critical qualification and definition has been provided
by Roy.
Roy and Richard then proceeded to nail the subject to the proverbial wall.

It is time to pause in grading exams to remind that analytic geometry and
circuit theory are not the same thing. In circuit theory (and practice) a
circuit/network/or-whatever is linear if, and only if, superposition is
satisfied. If superposition is satisfied, then the circuit in question is
linear.

This concept also has utility in some mechanical structures.

In English, it is not uncommon for a word to have quite different meanings
depending on where it is used. We all know this. Even when discussing
active devices such as BJTs and FETs one finds the word "saturation" used
differently depending on the device.

Obviously, large enough signals applied to any network that appears to be
linear with smaller signals will melt same - letting out the smoke that was
placed therein at the factory. Obviously, there are degrees of linearity.
A footnote is always understood to say: such-and-such network is acceptably
linear for signals larger than A and smaller than B.

... thus ends the lesson.

73, Mac N8TT
--
J. Mc Laughlin; Michigan U.S.A.
Home:
"Roy Lewallen" wrote in message
...
I can only hope that some of the readers understand.

Roy Lewallen, W7EL