Abstract: The electrical power harvesting from environmental energy such as thermal , light, wind, vibration permits low-power devices, few of which are conventionally powered by batteries. Low-power devices are used in variety range of industrial applications. Battery replacement or recharging is generally unattractive inside the devices because cost and difficulty of getting access to the built in embedded devices. Solar energy is most widespread form of energy and Photovoltaic (PV) technology is thus very useful in energy harvesting. The choice of appropriate PV module like size and conditioning circuit for output power is essential for effective operation. To improve efficiency commonly used technique is maximum power point tracking (MPPT) and good response is obtained for changing irradiation. At low light levels in indoor systems control and tracking circuitry itself may consume most part of the generated power which is not feasible. This paper shows the circuit which can work in indoor and outdoor applications but without having controller in it.

Keywords: PV panel, MPPT.