First a little background. In my lab physics class we performed a lab to determine the Feigenbaum constant. I decided to do my research project on period doubling in non-linear circuits. I started thinking about the RLD circuit and how I could make it more interesting by adding different non-linear components instead of a diode. I settled on a LED (because my department has a lot of monochromatic LEDs). So I am wondering how similar are LED's to regular old biased diodes. Do they have the same type of pn-junction and can I model them the same as I would for a diode? I was also wondering if anyone had a better way of determining at what voltage the bifurcations occur. Currently I have an old HP analog oscilloscope and a Tektroniks oscilloscope hooked up to it. The analog gives pretty pictures and a not so good estimate of the voltage, but the Tektronics oscilloscope gives a FFT of the signal which seemed to make finding the bifurcations easier (the number of frequencies used doubled and I believe that this is proportional to the number of periods.) Finally, can someone point me towards some journal articles where people have investigated different aspects of this type of circuit (outside of the articles published by Feigenbaum, which I already have). The source or cost isn't really important my university has access to most journals and those it doesn't can usually be obtained through other libraries in the area. Any help or advice you can give about this type of circuit would greatly be appreciated, I'm still in the literature review phase of the research and don't have anything concrete to work off of just yet.