A comprehensive kit for investigating the properties of silicon photo-voltaic (solar) cells as a source of useful power, in an interesting and practical manner. The kit comprises eight individual 0.4V 100 mA cells. These may be accommodated in the base 'tray' which provides physical support and facilitates interconnection of the cells using the connector strips provided. The cells may be linked in a variety of series, parallel or series/parallel combinations to give the desired output characteristics. Also included is a low consumption electric motor with mounting components, connecting leads and a small fan to illustrate practical use to which the system can be put. The kit is supplied with a comprehensive instruction booklet which gives background technical information on solar cells, advice on interconnecting the cells for the different types of application and suggested uses to which a small solar battery can be put. Dimensions of base tray: 110mm x 95mm.