This master’s thesis deals with the problem of thin film solar cells, their parameters and measuring. The introductory chapter describes the properties of individual thin-film technology, summarizes their advantages against the crystalline silicon cell. Another chapter is exclusively focused on thin-film cells based on amorphous silicon. There is described the manufacturing processes of amorphous cells and modifications performed during the manufacturing. One part of master’s thesis is dedicated to the description of basic electrical quantities and PV cell degradation mechanisms that negatively affect these electrical properties. It is explained in detail the most important degradation phenomenon called Steabler - Wronski effect. The master’s thesis describes standards regarding testing amorphous cells as well as method, how to achieve their performance stability. The practical part is focused on the testing of several single-layer amorphous cells that were exposed to degradation and regeneration effects. One part of the thesis is studying of a new method of testing of amorphous cell, where is necessary to determine whether it is the degradation or regeneration process. Measured values obtained from several types of measurements were compared, evaluated and displayed in the graphs. The recommendation for future testing of amorphous article is stated in the final chapter.