This part of IEC 62047 specifies terms and definitions@ and a performance testing method of vibration driven MEMS electret energy harvesting devices to determine the characteristic parameters for consumer@ industry or any application. This document applies to vibration driven electret energy harvesting devices whose electrodes with a gap below 1 000 ?? are covered by dielectric material with trapped charges and are fabricated by MEMS processes such as etching@ photolithography or deposition.