用来在水中进行声电或电声转换的器件。将电信号转换成声信号向水中发射的称“发射换能器”；将接收到的水声信号转换成电信号的称“接收换能器”，又称“水听器”。这种转换通常是利用某些材料的压电效应、磁致伸缩和电致伸缩特性来实现的。在每种情况下，施加某频率的交变电 Device for acoustic or electroacoustic conversion in water. The electrical signals into acoustic signals emitted into the water called “launch transducer”; the received water acoustic signals into electrical signals called “receiver transducer”, also known as “hydrophone.” This conversion is usually based on the piezoelectric effect of certain materials, magnetostrictive and electrostrictive properties. In each case, an alternating current of a certain frequency is applied