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I have searched for examples but the ones I found, as they do not explain.

I need plot histeresis in a schmitt trigger. I have examples but I dont know how I can plot this histeresis. https://www.circuitlab.com/circuit/z8bt4k/histeresis/ https://www.circuitlab.com/circuit/7mftcu/disparador-schmitt/ https://www.circuitlab.com/circuit/jnqc8n/disparador-schmitt/

First some technical points about your examples.

Your example:

https://www.circuitlab.com/circuit/z8bt4k/histeresis/

has no positive feedback. It is just a difference amplifier (it has input voltages applied to both inverting and non-inverting inputs to the amplifier).

Hence it has no hysteresis.

Similarly,

https://www.circuitlab.com/circuit/7mftcu/disparador-schmitt/

is just a x10 inverting amplifier.

Your circuit:

https://www.circuitlab.com/circuit/jnqc8n/disparador-schmitt/

is a schmitt trigger but it has unrealistic values in R1 and R2. With a TL081 type of opamp, the resistors would normally be in the kOhm range.

Also, it is not good practice to use a floating power supply as you have drawn. A single rail with one side grounded or a split supply is more usual.

As a general note, it is not a good idea to use an opamp as a comparator. They are not designed to withstand the large input voltage differences that are often ecountered in comparator circuits whereas dedicated comparator devices specifically are.

http://www.analog.com/static/imported-files/application_notes/AN-849.pdf

http://www.analog.com/static/imported-files/tutorials/MT-084.pdf

http://www.analog.com/static/imported-files/rarely_asked_questions/op-AmpsAsComparatorsv1.ppt

Now, about plotting signals in circuits with hysteresis.

First, you need to define exactly what you wish to plot against what.

1) You can do Time Domain simulations ...

You can set up a time varying input voltage source, V(in), and then plot V(in) and V(out) in the same vertical axis against time on the X axis so you can see where V(out) changes as V(in) varies.

You can add a couple of DC voltage sources set to the threshold levels and include them in the plot so you can easily see the trip levels.

You can sweep a parameter or a component value to see how the circuit behaves for different values of hysteresis and hence trip levels.

All this is illustrated here:

https://www.circuitlab.com/circuit/m38d7a/behavioural-non-inverting-schmitt-trigger-02-parameterised/

2) You can do DC Sweep simulatons ...

Sweep V(in) and plot V(out) to see where V(out) trips against V(in) as V(in) increases.

However, because CL will not allow you to set up a DC sweep with the start voltage higher than the finish, you will have to create a voltage source or a parameter that you can use in a switching role as a second swept parameter so that on the first sweep, V(in) goes from low to high and on the second it goes from high to low so that you can see V(out) vs V(in) for a rising and for a falling V(in).

It get's more complicated if you want to see the classic hysteresis loop type of plot like this:

http://en.wikipedia.org/wiki/File:Hysteresis_sharp_curve.svg

from "Non-inverting Schmitt trigger" in here:

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

then you also need to do some cleverness to get the plot of V(out) so that it looks right:

https://www.circuitlab.com/circuit/84tt9t/how-to-set-up-a-sweep-to-see-a-hysteresis-loop/

That may be rather a lot to take in but I hope it is of some help.

I think you did not understand, and the example does not help me . I try whit a representation of advanced strokes whit this example https://www.circuitlab.com/circuit/75p8ye/ejemplo-memristor/ is so-so a histerises, but I could not represent a curve V vs I.

If you simply need to know how to plot V vs I or similar then does any of this help?

The sections on:

Plotting Outputs

and

DC Sweep Simulation in:

https://www.circuitlab.com/docs/the-basics/

And some examples...

https://www.circuitlab.com/circuit/nu8w4b/sweeping-a-voltage-source-demo-01/

https://www.circuitlab.com/circuit/47ngm4/n-parameter-sweep-in-edited-led-model-01/

https://www.circuitlab.com/circuit/y42f62/n-parameter-sweep-in-edited-led-model-02/

:)