In this final paper, we have explained the transformation of the chemical energy into electricity by means of fuel cells. Theoretical part of the final work describes the fuel cells, their application and the principle of operation are described. Fuel cells are still relatively young technology with great potential and great limitations. Ecologically pure energy with a very wide area of ​​application, with high energy utilization, which uses fuel that can be produced from many sources, offers many possibilities. The cost of materials required for fuel cell generation and fuel-producing and storage-related problems that may be dangerous, and the lack of high-capacity infrastructure, limit fuel cells to the use of fuel cells. In the practical part of the final work, 4 experiments were performed. In the first experiment, it was observed that oxygen influences the fuel cell's strength and it is also observed that hydrogen consumption depends on the current of consumers. It is concluded that the consumption of hydrogen increases proportionally with the increase in the current of consumers, and by adding oxygen increases the voltage. In the second experiment, the current - voltage characteristics and P / I characteristics of the fuel cell were determined. Increasing the current of the fuel cell voltage decreased proportionally. In the third test, the computer is fuel cell efficiency. Hydrogen consumption is growing proportionally to the power of the consumer. In the fourth experiment, the effect of the chimney in fuel cells was observed. The effect of the chimney is the movement of gas due to the buoyancy of the Arhimed Law. Growth occurs due to differences in air density, which is due to differences in temperature or humidity. The difference in air density causes the difference in the pressure that makes the effect of the chimney. Due to the effect of the chimney, higher voltage and current occur.