2014 Volume 134 Issue 10 Pages 870-875
Malfunction and failure of electronic equipment can result from the occurrence of electrostatic discharges. Such problems increase as the use of low-voltage electronic devices increases. There are relevant test methods available for electronic devices, such as the human body model (HBM) and the field-induced charge device model (FICDM). In contrast, there are no test methods available for electronic equipment when a charged human body passes in front of a metal box that encases electronics. The authors measured the induced voltage generated in a metal box encasing electronic equipment when a charged body passes in front of the metal box. We have previously observed the occurrence of positive and negative induced voltages that are generated by the movement of a charged object. In this study, we focus on the induced voltage generated when a charged object moves away from a metal box. This situation represents that of a charged human body moving away from the metal box encasing electronic equipment. The measured results show that the value of the induced voltage is -300% greater than the voltage of a moving charged body under these experimental conditions. The results are compared with those calculated on the basis of capacitances and electric charges. These results show that the voltages induced in an ungrounded metal box, when a charged body moves away from the metal box, become large enough to cause malfunctions and failure of electronic equipment.