Figure 99 comprises four schematic line drawings labelled 'PV cell', 'module of cells', 'array of modules' and 'complete system'. They should be considered in the following order. A PV cell is represented by a solid rectangular object comprising three layers. The central layer is much thicker than the top and bottom layers. There is additional detail on the top of the object. The module of cells is represented by a rectangle containing 8 squares arranged in a pattern of 4 rows and 2 columns. By implication, these squares are PV cells. Two vertical lines, labelled '12V d.c. output', protrude from the top of the module. The array of modules is a perspective drawing of 6 modules arranged in an array with 2 rows and 3 columns. The modules are inclined at an angle of about 30 degrees to the horizontal. The complete system is represented by a hierarchy diagram comprising 3 rows. The top row comprises 4 modules. Below the modules there is a rectangle labelled 'power conditioning' and below that another rectangle labelled 'load'. A vertical line goes down from the bottom of each module of cells. These 4 lines are all the same length. They turn horizontal to meet together in the middle of this diagram directly above the power conditioning rectangle. They then turn vertically down as a single line connecting to the top of the power conditioning rectangle. A line from the bottom of the power conditioning rectangle connects to the top of load rectangle.