Re: [Qucs-help] controlled resistor element?

[Stefan J. <st...@gr...>]

Am Di, 1.12.2009, 00:01 schrieb Richard Finstad:

> Stefan.

Hello Richard,

>     Thank you! As I stated
> in my original email, I need a current controlled resistor. I
> haven't used EDD elements (I'm a SPICE user), but this should
> work well. I'm primarily module power distribution at module
> and package levels, and need the controllable resistor to model
> ASIC supply demand.

In this case you can use EDD (if you can explicitely formulate the
resistor formulae, see below).  Place a EDD in schematic and choose
1-branch.

In order to formulate a normal resistor, type:

  I1 = V1/50k

In order to formulate any dependency type:

  I1 = f(V1)

whereas f(V1) can be alomost any kind of function depending on V1.

V1 stands for voltage across the 1st branch, and I1 for the current
through 1st branch.

If your resistor is defined by function R=f(I1), then consider R=V1/I1,
thus you have:

  V1/I1 = f(I1)

Now try to reformulate this into:

  I1 = f(V1)

that means you need the explicite form for I1...

>  Another analysis I'd like is to use Fourier transforms to convert a
> repetitive transient simulation into a AC simulation.

A AC simulation at certain frequencies, correct?

> The interconnecting
> network would be linear with a simple source.

Source at certain (single) frequency?

> I think of this as
> 'harmonic balance' but I don't believe this is what your harmonic balance
> analysis does. I would need to build the individual netlists myself with
> separate sources based on an FFT, then simulate with Qucs, and finally
> recombine the results myself. Is my understanding correct?

If the network AND the source are both linear (source = single freq and
network linear), then you can do simple AC, don't you?

Best regards, Stefan.