Piezoelectric is a device which works based on piezoelectric effect and generates electricity by converting mechanical, used in small power engineering. The piezoelectric was discovered in the late 19th century and became widely used in electronics and radio engineering. The phenomenon consists in the appearance of a potential difference on the electrodes, if you make the effort to the piezo.
The piezoelectric materials have two ways of energy conversion, therefore, there are two types of devices:
1. The piezoradiator they transform directly, the mechanical energy is converted into electricity.
2. The piezo motors – they are all going in the opposite direction.
When there was a piezoradiators developers began to think about where you can actively use these devices. There were options conversion of noise from the street, load which creates living beings in motion, movement of wind and waves. To date, there are few examples of using piezoradiators. In the capital of Japan at one of the metro stations is set piezoradiator. The flow of passengers is ensured by a constant pressure, as a result of electricity, which produces enough to ensure the operation of the turnstiles. In the UK at one of the discos the pressure that is created by the movement of visitors, nourishes lighting. Also have become commonplace piezosurgery. In Israel, scientists are developing a project to produce electric energy highway. By calculations it turns out that 1 kilometer of road can generate up to 5mW.
What happens in piezoelectric during the generation of electricity? The piezoelectric element has an asymmetrical crystal lattice when subjected to a shifting of atoms. This displacement of the atoms and creates an electric field, resulting in the electrodes a potential difference. The main difference from the capacitors that retain a charge, a piezoelectric element stores the charges as long as it affects the load. As soon as the mechanical action stops, saves the charges disappear. Therefore, the piezoelectric elements produce small current strength, and the element itself has a large internal resistance. Piezomaterial have many characteristics, but to evaluate the efficiency of generation of electricity is one important characteristic is the piezoelectric modulus. The size of this module varies from 200 to 500 PC in Newton. The modulus value depends entirely on the properties of the piezo and not depend on the dimensions of the piezoelectric element. Therefore, the increase in its size will not lead to more efficient operations. Piezosurgery generate electricity to 2.2 MW, but the discharge lasts only 0.08 nanosecond.
Given the short duration of the discharge, piezoradiators suitable for small scale power generation. Here you need low power, such devices well meet the small needs. It could be small appliances, video surveillance systems, diagnostic equipment and mobile phones.
