Building a Piezoelectric Generator
Students learn how to build simple piezoelectric generators to power LEDs. To do this, they incorporate into a circuit a piezoelectric element that converts movements they make (mechanical energy) into electrical energy, which is stored in a capacitor (short-term battery). Once enough energy is stored, they flip a switch to light up an LED. Students also learn how much (surprisingly little) energy can be converted using the current state of technology for piezoelectric materials.
The ceramic piezoelectric element used in the activity.Copyright 2014 Matthew Zelisko, GK-12 Program, University of Houston.
Piezoelectric materials have the unique and useful property of being able to transform mechanical energy into electrical energy, and vice versa. This gives piezoelectric materials a wide range of potential applications from sensors and actuators to artificial muscles. One of the most interesting applications is in the field of energy harvesting, where piezoelectric materials are used to convert mechanical energy that is typically wasted into a source of electrical energy. However, the technology of currently available piezoelectric materials and methods is unable to produce a sufficient amount of energy, so engineers are researching how to improve piezoelectric energy harvesting devices.
After this activity, students should be able to:
- Explain how the piezoelectric generator works and from where it gets its energy.
- List multiple energy-harvesting applications for piezoelectric materials.
- Calculate how much energy is stored in a capacitor and how much is converted by the piezo element.