Abstract A general formulation for coupled electromechanical modelling is specialized to the analysis of transducers used for simultaneous sensing and actuation. Important issues related to modelling and implementation of a simultaneous piezoelectric sensor/actuator are investigated. Open and closed loop experiments performed on a cantilevered beam test specimen are described, and substantial predictive capability is demonstrated. The results highlight the utility of the simultaneous sensor/actuator for vibration control. The sensitivity of both open and closed loop results to representative errors introduced in the implementation of the transducer is demonstrated analytically and experimentally. The simultaneous sensor/actuator is also sucessfully implemented in an open loop experiment using an active piezoelectric strut in a truss structure. The ability to correctly predict experimental results is also proven in the truss case.