Human Dynamic Potentiometer Design and Its Application in an Electrostatic Protected Area

To study the risk of electrostatic discharge (ESD) caused by human activities in an electrostatic protected area (EPA), an innovative contact mode human body (HB) dynamic potentiometer is designed. It uses a coaxial capacitor voltage divider (CVD) to achieve high-accuracy performance. The temperature, coaxial capacitor medium thickness, and relative position effects on the CVD performance are simulated and measured. It utilizes LabVIEW development software to realize data visualization, analysis, and dynamic display of time-domain waveforms. The HB dynamic potentiometer test results show that the voltage measurement range is 0-+/- 6 kV, the measurement error lower than 1 kV is better than 2%, the system response time is less than 1 ms, and the passband is better than 1 kHz. Using this potentiometer, the voltage generated by HB in different modes of action in the EPA was studied, for example, the cases of walking in a fixed pattern, walking randomly, and raising and lowering the feet. The ESD voltage is predicted by using the Chebyshev inequality over a long-time duration, which corresponds to 2-3 times the measured voltage over a short time duration. This study found that compared to the pattern walk motion, the random walk increases the HB model (HBM) voltage by a factor of 1.5-2. The foot lifting activity can increase the voltage by a factor of 8-12. Finally, the relative humidity (RH) decreased from 45% to 30% by increasing the HBM voltage by a factor of 2-3 for both walking and foot lifting and lowering motion. This result can be used to support the electrostatic protection standard in the EPA.