GENERATION OF ELECTRICITY BY PIEZOELECTRIC EFFECT

The increasing desire for completely self-powered electronics has caused the amount of research into power harvesting devices to become progressively larger over the last decade. With the advances being made in wireless technology and low power electronics, sensor are being developed that can be placed almost anywhere. By utilizing these untapped energy sources electronics that do not depend on finite power supplies, such as the battery, can be developed. One source of typically lost energy is the ambient vibrations present around most machines and biological systems. This source of energy is ideal for the use of piezoelectric materials, which have the ability to convert mechanical strain energy into electrical energy and vice versa. In particular, energy harvested parasitically from human movements has garnered much discussion. Perhaps the most energy abundant and readily utilized form of ambient human power is walking.

The project aims at building a circuit using Piezoelectric material and various other electronics, which could be installed at a suitable location to harvest energy by piezoelectric effect.We have made a LED glow just by tapping a special material with our finger.

Piezoelectric Effect

The ability of certain materials (Piezoelectric materials likes quartz, tourmaline, Rochelle salt)  to generate an electric charge in response to applied mechanical stress. The word Piezoelectric is derived from the Greek piezein, which means to squeeze or press, and piezo, which is Greek for “push”.

PRACTICAL WORK

AIM :
To demonstrate piezoelectric effect and store the generated electric energy in a capacitor.

APPARATUS :
piezo transducers, thin wires, 4 diodes, (22 micro farad,250V) capacitor and soldering iron.

PROCEDURE :
1) Take a piezo transducer and solder the wires on it a shown in figure.

2) Take 4 diodes and make a bridge connection as shown in figure.

3) Form the circuit as shown in the figure consisting of Piezo transducer, rectifier and the capacitor.

4) Install the circuit in your or tap on the piezo material with finger repeatedly.  Force exerted due to your weight and walking/ tapping will exert stress on piezo crystal and a AC voltage will be developed across it which will be converted to DC via the rectifier and then stored in the capacitor.

5) For testing purpose attach a LED at the terminals of the capacitor. LED should glow.

 [soldered piezoelectric material ]

[CIRCUIT DIAGRAM ]

 [Multimeter reading ’18.2Volts’ after 100 taps on piezo transducer ]

 

RESULT  :
1) More the number of piezo material connected in series more is the output voltage but not proportionate.
2) More is the Stress applied, more is the output voltage.


Download the entire project CLICK HERE