Re: LTspice Question

On Feb 20, 6:09 pm, kensm...@xxxxxxxxxxxxxxx (Ken Smith) wrote:
In article <5bc28$45da65ab$45011502$8...@xxxxxxxxxxx>,

amdx <a...@xxxxxxxxxxx> wrote:
Hi Ken,
I don't quite have it,
I'm plotting (v(in)) which is the voltage out of the signal generator
(with internal resistance) feeding a filter. The plot shows voltage
amplitude
and phase. If I right click and change (v(in)) to re(v(in))

Stop at this point and admire the trace.

Now click on the same node again.

Look at the two traces. You now have the "re(V(in))" and just "V(in)" in
the top of the graph.

Now, move the mouse over the "V(in)" label at the top of the graph. Click
and edit like you did before.

then I still
need to do
something with im(v(in)). I either have improper syntax or I'm putting it in
the
wrong place.

You missed a step.

If I get it right, what is the label on the left y axis? It seems to be
voltage I was
looking for ohms.

You will only be able to plot voltages or currents. If you force a
current of 1A through an impedance, you get a voltage equal to that
impedance so this is how you can get impedances to plot.

Not true! If you plot V(in)/I(source) -- that is, a function which is
a voltage divided by a current -- it will display in ohms, complete
with the Omega symbol. That way, you can use any current you want
(not that it makes a difference for an AC analysis, which is taken to
be linear around an operating point -- but it's nice for transient
analyses), and properly display the result in ohms. This works for
quite a few other units, too: volts*current is power, etc.

Cheers,
Tom

.