From: David Roberson
Could you offer a simple description of the behavior of the negative differential resistance function that you mention? Looks like you are already doing something similar. Wiki has an entry for the electronic version. The image of the curve is an ascending double hump, so if your model accommodates that already, then that may be why it is so intuitive. If one is plotting P-in vs. P-out then there is good control functionality to the top of the first hump, where the negative feedback would start to show itself. https://www.google.com/search?q=negative+differential+resistance&client=firefox-a&hs=bBT&rls=org.mozilla:en-US:official&tbm=isch&tbo=u&source=univ&sa=X&ei=JKTFUo6jBcvxoASVpoCABw&ved=0CDwQsAQ&biw=1146&bih=675
