# Real diode behaviour modelling

In high frequency, this plots the input voltage and the current in a simple circuit with a resistor and a diode.

The behaviour I see is that the diode remains forward-biased for longer than an ideal diode would, but as soon as it does it goes back to the usual, perhaps exponentially in a very low time, without any phase shifts.

I have been attempting to (macro) model that particular behaviour of the real diode using an ideal diode and other components (capacitor, resistance, inductor), but so far, failing miserably

Short question is, what could I add to the black box of an ideal diode for it to behave that way?

I would appreciate, should you come up with something, to know how you went about thinking about this, since learning is the only purpose of this question.

Thanks a lot

-
Have a look at the Shockley equation for the ideal diode, and the various additions to it. The Wiki diode page is a good place to start, and then follow this up with the page on Diode Modelling – Oli Glaser Aug 31 '12 at 11:19
Thanks @OliGlaser, I am taking a look – Rojo Aug 31 '12 at 14:22
I don't understand. The trace you're showing us comes from a simulator, right? So, by definition, you already have a model for the behavior of the diode. I think you'd learn a lot more by studying that model than by building your own ad-hoc model. – Dave Tweed Sep 1 '12 at 11:44
@DaveTweed on the one hand I am interested in the real diode modeling. On the other hand, and this was the hand I wanted to focus on when I asked, I took this as an exercise: what if I had an ideal diode (perhaps the 0-order model even) and I wanted to generate a response such as the one in the image, for some given set of values and frequencies, by adding capacitors and basic components? I couldn't do it myself after trying. I am trying to get comfortable with circuits with diodes AND components with memory (inductors, capacitors), so I asked to see how people think about these things – Rojo Sep 1 '12 at 13:16