The usage of renewable energy has been developing dramatically due to the concern about lack of fossil fuel energy. This can be clearly observed in the government budgets in R D. Solar energy by its special characteristics such as its availability in the whole world, play major rule among the renewable energy sources. In this thesis, solar cell is considered more as the electrical source and less as the physical relations which describe inherent characteristic. To begin with, the evolution history of solar cell is discussed. An overview of solar cell characteristics is presented and maximum power point tracking (MPPT) methods are described. Then, a circuit-oriented model for solar cell is suggested which is suitable for simulation purposes. The general P O algorithm is investigated comprehensively and the different methods of employing this algorithm for DSP are simulated. After that, a simple method and an upgraded method are suggested to be implemented with microprocessors which improve the speed and accuracy of the previous methods. At the end, by reviewing inexpensive analog approaches, the various analog implementations of MPPT algorithms are simulated. For efficiency improvement, soft switching interface converters are adapted to MPPT and one of these algorithms is implemented on a ZCT buck converter. The presented experimental results justify the theoretical analysis. Key Words Solar Cell, Maximum Power Point Tracking, Perturb Observe, Soft Switching