Methods of making piezoelectric transducers from very thin sheets of polyvinylidene fluoride (PVDF) are discussed, together with techniques for calibrating these devices, particularly for underwater operation. Parameters measured include receiving response, source level, beamwidth, characteristic impedance and variation of impedance with frequency. Consideration is also given to the dependence of receiving response on the poling fields and temperatures used in making PVDF transducers. Because of their broadband response thin sheet PVDF transducers have been shown to be ideal for monitoring the true form of acoustic pulses underwater.