The AP (action potential) simulator is a tool for studying the electrical behavior of an excitable membrane. Through computer simulations, the user can perform virtual experiments with nerve stimulation. Basic experiments involve injecting current pulses of any type. The user also has the option to adjust any of the parameters in the model to investigate how they affect the behavior (e.g. ionic conductances). The simulator is specifically designed to model a human node of Ranvier and is based on a mathematical model originally published by Schwarz, Reid, and Bostock (Schwarz et al. 1995).