The Correlation of Rising Slope and Speed of Approach in ESD Tests

The rising part of the current waveform when discharging an electrostatically charged person or an ESD test generator shows some phenomena which have not until now been explained satisfactorily. This paper describes an attempt to come closer to understanding these effects using both an experimental and a numerical simulation of the phenomena. A special rotating system to simulate a defined, variable closing speed of the contact has been built. The length of the arc is also measured and it can be shown that a strong correlation between arc-length and rising slope at a given voltage exists. This result is compared with a theoretical model using the law of Toepler. This model can be used to explain some of the phenomena observed with the rising slope of ESD's.