The diagrams show a structure that is used to generate electricity from wave power.
A comparison of systems that can be used to produce electricity by wave power is shown in the diagrams. In general, both systems use same equipments such as chamber, column, and turbine. These same structures are able to generate electricity by using air pressure which blow from under and above the turbine.
To begin with, in picture A, the chamber is located beside cliff or sea wall. Then, when wave of seawater are pushed to the chamber, it will be directed to the turbine. There is a rise volume of water in chamber which is able to increase the pressure of air. Flow of air and its pressure can rotate turbine in column clockwise and after that electricity is generated.
On the other hand, on another picture, the flow of air comes above the turbine. It is because reducing energy of wave after water turn out the chamber creates small pressure of air in the chamber. Therefore, air from outside chamber is flowing to the column and rotates turbine. Lastly, that rotation produces the electricity.