A transducer is a device that converts from one energy form to another. A piezoelectric transducer converts mechanical energy to electric charge, and vice versa. These materials are usually crystalline or ceramic solids, and can also be organic materials such as DNA and some proteins. The basic concept is that applying a stress (a force) to a piezoelectric material will cause it to build up an electric potential which can be measured (with a voltmeter). These materials can be useful in applications where detection of sensitive forces are desired, such as in microscopic probes and detection of sound waves.

One very common use of the piezoelectric effect is your basic quartz watch. The quartz crystal vibrates at a very precise frequency which can be used to tune the speed of the clock.

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