96 ________________  Corresponding author: K.Vishwanath  E-mail address: akvn87@gmail.com  Doi: http://dx.doi.org/10.11127/ijammc.2014.08.07 Copyright@GRIET Publications. All rights reserved. Advanced Materials Manufacturing & Characterization Vol4 Issue 2 (2014) Advanced Materials Manufacturing & Characterization journal home page: www.ijammc-griet.com Review And Scope Of Scavenging micro Energy using Piezoelectric materials K. Vishwanath Allamraju 1 ,K. Srikanth 2 1 .Research scholar, Mechanical Engineering Department, NIT Warangal, India 2 .Assistant Professor, Mechanical Engineering Department, NIT Warangal, India A R T I C L E I N F O Article history: Received: 26-06-2014 Accepted: 28-07-2014 Keywords: Piezo electricity, Energy Harvesting, Vibration PZT material A B S T R A C T This paper reviews the energy harvesting for micro level devices such as mobile phones, low powered signal lights and energy storage batteries by using Lead Zirconite Titanite (PZT) with the help of vibration on cantilever beams and batteries. Recent advances on micro power portable devices require limitless battery life for improving performance. A lot of energy is being wasted which is around us and also research has been conducted to develop energy harvesting devices by using PZT materials. This paper gives innovative ideas to develop energy harvesting devices for future scientific community. Introduction The term energy harvester is defined as the generator device undergoing either vibrations or pressure due to a specific form of excitation or force. Energy harvesting from ambient waste energy for the purpose of running low powered electronics has emerged during the last decade as an enabling technology for wireless applications [1]. With recent advances in wireless technology the energy harvesting is highlighted as an alternative of conventional batteries. There are two types of energy harvesting. One is macro level energy harvesting and another one is micro level energy harvesting. Wind energy, solar energy and tidal energy comes under macro level energy harvesting because they produce power in KW or MW but whereas power will be generated with the help of PZT’s is in mW or µW by using either by mechanical stress strain or vibrations therefore it is called micro level energy harvesting. In this paper the energy harvesting is limited to Micro level energy harvesting. Since piezoelectric material is used for converting mechanical energy into electrical energy it is great power source for developing micro level energy harvesting devices and wireless sensor network systems. Piezo electricity is a form of coupling between the mechanical and the electrical behaviors of ceramics and crystals belonging to certain classes. These materials exhibit the piezoelectric effect, which is historically divided into two phenomena as the direct and the converse piezoelectric effects. When a piezoelectric material is mechanically strained, electric polarization that is proportional to the applied strain is produced. This is called the direct piezoelectric effect and it was discovered by the Curie brothers in 1880.When the same material is subjected to an electric polarization, it becomes strained and the amount of strain is proportional to the polarizing field. This is called the converse piezoelectric effect or inverse piezoelectric effect. The constitutive equations for a piezoelectric material are given by [2][3]. It can be seen that the first equation is the Hooke’s Law when electric field is zero and the second is Gauss’s law of Electricity when stress is zero.           Where, δ - Mechanical strain σ – Mechanical Stress Y – Modulus of Elasticity (Young’s Modulus) d- Piezoelectric strain coefficient E – Is the electric field D – Electric Charge Displacement ε – Dielectric constant of piezoelectric material