**6. Conclusions**

The microscope illuminated by solar cell. Some medical devices operated by using solar energy, which this energy produces a DC current. These devices modulated by canceling step down transformer and rectifier, and offered appropriate DC current by sizing photovoltaic cell and a charging battery or used inverter to convert DC current to AC current. Solar cell is more expensive than electricity power, but it can use in areas where there are no electricity power.

In comparison to other energy sources such as coal, natural gas, nuclear, wind, and hydro-electric, solar energy is one of the least cost effective. For the most part, the exorbitant cost of solar energy is due to the high cost of manufacturing high quality solar panel material that has high energy conversion efficiency. Today, most cheaply made solar cells have an energy efficiency of about 14% while the higher quality materials achieve efficiencies of about 20–25% solar energy is still relatively expensive to a consumer.
