Both mechanical and electronic devices often rely on transducers as part of their functional structure. These devices have been around for some time, and have taken on a number of different varieties and applications.
Transducers are devices that take one form of energy and convert it into electricity or another type of energy. For example, microphones, a common type of transducer, convert sound into electricity.
Applications of transducers vary widely. Some are used in medicine, such as in sonograph machines, while others are used in music engineering and recording. Still other transducers are used in complex mechanical systems and even in safety systems like train brakes.
The material a transducer is made of can directly affect its application. Most transducers are very sensitive to things like pressure or temperature. Some are sensitive to the point that they become unstable in some systems. This is why train brake systems have reverted to using more stable transducers, like those made of plasma-enhanced polysilicon, a stable material.