This guide relates to dynamic measurements of piezoelectric ceramic resonators. IEC Publication 302, Standard Definitions and Methods of Measurement for Piezoelectric Vibrators Operating over the Frequency Range up to 30 MHz, which is mainly intended for the case of quartz crystal units, is also applicable to the measurement of piezoelectric ceramic resonators. There are, however, two important differences between the case of quartz crystal units and the case of ceramic resonators. Firstly, the high electromechanical coupling associated with ceramic resonators makes the determination of the parameters quite different from those of quartz crystal units. Secondly, not only resonator parameters but also material constants are frequently required to be evaluated in the case of ceramic resonators. This guide has been compiled to supplement existing publications with particular attention to these two points. Certain other characteristics of piezoelectric ceramics are considered as beyond the scope of this guide, in particular, ageing and high signal non-linearities. These characteristics are related to domain effects in ferro-electrics and are very complex. An introductory review of the admittance characteristics and equivalent circuits of ceramic resonators vibrating in simple modes is followed by methods for determining resonator parameters, and in turn material constants.