Disadvantages Of Electrical Technology

ABSTRACT
This chapter presents a literature view about vibrational energy harvesters which will and will have a great scope in electrical technology concerned to the production of the electrical output by using light (which usually deals with the Photodiodes, Light Dependent Resistor (LDR) and various other equipment’s), Electromagnet and human body. Now a days there are various equipment’s which can convert any other form of energy in the electric energy, but they have some of the disadvantages that their production cost is high, requires high maintenance and supervision. This disadvantages can be somewhat overcome by producing electric energy by human generation, electromagnets and by light. This book deals with the various generations level

The humanbody provides multiple sources of energy that can be harvested.The necessity of providing energy to wearable computing devices made theconversion of human motion into useful electrical energy. For example, in gyms, there are some equipment’s, such as exercising bicyclesthat have their instrument panel powered by the user who is exercising. For example, the energy from human motion is already used to power wrist watches [3]. Energy harvesting of electromagnetic radiations is also possible with thehuman body.A very important class of applications, in a human energy harvesting environment,is the implantable biosensor. There are some requirements for these sensorsystems, which are the reduced size, the complete absence of user observation,once the applications have been deployed into the body. All of these requirements come from the factthat the applications are to be deployed inside the human body.An increased challenge exists, when using the human-originated energy sources. When compared tosources originated in an industrial or outdoor environment, a single human bodyprovides a reduced amount of power. The best placeto put a sensor powered by mechanical means would be in a limb, because this zoneis prone to have a greater mechanical activity. The power generated from a vibration Harvesters in a human application is presented,

This temperature is due tothe metabolism, which has a power 58.15 W/m2 over the body surface. A normaladult, with an average surface area of 1.7 m2, in thermal comfort and regularmetabolism, has a heat loss of approximately 100 W. However, the metabolism canprovide a value as low as 46 W/m2, while sleeping, or as high as 550 W/m2, whenrunning at 15 km/h. During a common workday, sitting at an office, this value canbe 70 W/m2, corresponding to a power dissipation of 119 W and a burn of about10.3 MJ during a day [5]. The thermal gradient is established between the bodytemperature and air around the body. Even if the generated energy is not enough tosupply a sensor node on a permanent basis, the usual strategy is to accumulate theharvested energy, so that a transmission is enabled from time to time, powering thetransmitter with the energy that has been harvested and stored, in the meantime.In general, as documented in [4], one has power densities of about 300 and20 μW/cm3, representing the limits for kinetic and thermal devices, respectively, whilethe user is running. The values of 30 and 10 μW/cm3 are the power density limits if theuser is walking. The present challenge, which is still under active research, is the means to obtain the correct adaptability for the harvester, in order to match the electric and the thermal impedances, if the body of the user is undergoing a running or a walking regime. Some specific applications