Discussion Forum

I'm trying to simulate the thermal runaway phenomenon of a conductor. I modified the electrical resistivity of the material in order to mimic the NTC behaviour as measured experimentally. At the right voltage applied the temperature start to increse exponentially due to the uncontrolled positive feedback. The problem is that the impedance of the sample is chaning during the test but the initial voltage applied remained constant. This mean that when the sample resistivity falls to very small values the current increases without limits. In the reality every power supply is characterized by a maximum current, when it is reached the voltage start to decrease due to the increasing conductivity of the material. How can I simulate this simple behaviour? I tried to impose a maximum power to the terminal, and an initial voltage, but in those condictions the simulation fails witouth reaching the convergence.