Some results in measuring static decay

For qualifying materials to be used in ESD protected areas (EPAs), surface resistivity or static decay of an electrical charge generated by triboelectricity may be measured. In physical aspects there is only one method for measuring static decay of this charge by a field mill meter but there are three methods describing how to apply the electrical charge to the surface of the material: the FTMS1O1C (method 4046), the Corona Charging and the Direct Contact Method. Although they seem to do the same thing (that is to deposit some charge on the surface) there are often large differences in the measured decay time using the same probe. These differences are demonstrated and the background research is discussed.