are caps and coils linear circuit elements?

[John Larkin]

On Mon, 4 Feb 2008 05:48:05 -0800 (PST), Lax <Lax.Clarke@gmail.com>
wrote:

On Feb 2, 7:25 pm, John Larkin
jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Sun, 3 Feb 2008 10:46:08 +1100, "Phil Allison"





philalli...@tpg.com.au> wrote:

"Mark Zenier"

** Wot a fucking PITA wanker.

Phil Allison
"Lax"

**   Fuckwit Groper alert !!

iv curves of caps and coils are notlinear, so are they nonlinear or
linearcircuitelements?

What is the definition of alinearcircuit?

**  Jesus H. Christ you are a dumb turd.

 http://en.wikipedia.org/wiki/Linear_circuit

.......  Phil

Charters and description lines.

sci.electronics.basics Elementary questions about electronics.

"A forum for discussion of electronics where there is no such
thing as a stupid question.  Beginners questions.  Discussion of
electronics education.  Requests for other sources of information."

** The OP is dumb turd for  NOT  making any effort to find his answer on
Google and instead preferring to WASTE  the time of others here.

Maybe he tried. Maybe he found a heap of equations that he didn't
understand. Maybe he wanted to talk about it.


This is true. I actually checked Wikipedia also, but didn't
understand the whole sinusoidal response definition. In my head I was
using a cap's (or coil's) iv characeristic and a randon input into
this circuit:

Vin o------/\/\/\/\-----o-----| |-------GND (output across cap..
middle node).

I was thinking to myself, if I place a random voltage waveform at Vin,
I certaintly won't be guranteed an ouput that is linear with respect
to it. For example, a triangle wave input doesn't result in a
triangle wave output.

So this is why I was thinking to myself: "why is this circuit linear?
Rs are linear, but if Cs were also linear then the response to any
input waveform should be proportional to it."

But now I get that the term "linear" is only for sine wave inputs.

Not so. If a network (or component) has any arbitrary forcing input S,
and has some corresponding output Y, then the network is linear if
increasing the amplitude of S produces an exactly increased output Y.

So if S produces Y

then if

N * S produces N * Y

for any value of N, then it's linear.

A linear network can have an output that looks very different from its
input, like your example of a triangle going in but some other
waveform coming out. A passive lowpass filter can turn a triangle into
a sine wave, but a passive lowpass filter is still a linear network.
Double the triangle input and you'll get double the sinewave output.

One of the consequences is that if you apply a sine wave to a linear
network's input, you can only get a sine wave out. A linear network
can change the phase and the amplitude of frequencies that pass
through it, but it can't generate new ones.

What's sort of cool is that if you apply a sine wave to a linear
gadget and get some output, and you plot the input and output
waveforms against each other (XY plot on a scope) the only curves you
can trace are the various/degenerate versions of an ellipse.

Phil is obviously nonlinear.


John