With the increasing demand for tiny devices and the development of MEMS (micro electro mechanical system) technology, Micro-EDM has brought scholars to pay attention on it more and more. It is widely used in aerospace, medical, mold, micro-electronics devices, biotechnology, micro-sensors and micro-electrical manufacturing and so on. Accurate, stable and efficient micro-EDM system is always researchers pursuit of. Discriminating system for discharging status is the key parts of machine tool servo sy...