Electrostatically Induced Voltages Generated in Ungrounded Metal Box and on the Box When Charged Body Moves Away from the Box

The electrostatics phenomenon is frequently used in photocopiers and other applications, but it is a source of malfunctions or failures of electronic equipment. The electronic equipment of a personal computer, etc. occasionally malfunctions owing to the occurrence of electrostatically induced voltages generated in the metal box housing of the equipment. Malfunctions or other failures of an electronic device used in electronic equipment can occur when induced voltages of 10 V or lower are generated. The voltage of a charged human body can occasionally exceed 10 kV in an office. Thus, when such a charged body moves near the metal housing of electronic equipment, a high induced voltage can be generated in the box. In high-voltage engineering, voltage measurement using the Paschen voltage of an electrical spark gap is frequently performed. In the experiments of the present study, the induced voltages in an ungrounded metal box and on an ungrounded metal box are measured when a charged body moves away from the metal box. The induced voltage generated in the ungrounded metal box is measured using a spark gap and an electromagnetic-wave sensor. The results show that the induced voltage generated in the ungrounded metal box is −1.2 times the voltage of a charged body when the charged body moves away from the metal box. The results are helpful for solving such electrostatic problems and designing electronic equipment.