A method and an arrangement of tracking a selected power point of a photovoltaic system is disclosed, in which method an operation point of the photovoltaic system is changed based on the change of operation point and a change of power generated by the photovoltaic system. The medical device can include a hollow tube with a main channel and a separate channel, a cap with an inflation port and a hollow flexible stem fluidly connecting the inflation port and the separate channel. A locking hole is formed through the moving plate. The sides of the base body and the counter body, facing the flexible ribbon cables, are provided with complementary recesses or projections by which means the flexible ribbon cables can be guided to form a cable grip. The organic thin film layer is then exposed to a plasma. A second inductive coil fixedly mounted in spaced relationship to the first inductive coil.