Statistical measurement of burst discharge currents through fingertip from charged human

To understand the characteristics of human electrostatic discharges (ESDs), using a 12-GHz digital oscilloscope, we measured discharge currents injected into an IEC (International Electrotechnical Commission) current calibration target through the fingertip from a human body charged at a voltage of 300 V. Occurrence frequencies of the current waveforms and their cumulative relative frequency distributions were investigated. As a result, we confirmed that the finger touch causes burst discharges having current peaks of 60-ps rise time but a few ten milli-amperes, while the hand-held metal produces a one-shot discharge of the current peak with five-to-six amperes and 45-ps rise time. It was also found that the fingertip provides discharge peak currents that vary according to a log-normal distribution, while the hand-held metal bar gives current peaks following a normal distribution.