9 Optical instruments and apparatuses, namely, optical receivers, optical transceivers, optical data links for use in solar energy plants; optical lenses for solar energy plants, in particular for photovoltaic installations; apparatus and instruments for conducting, switching, transforming, accumulating, regulating and controlling electricity, namely, electrical switches, electrical transformers, as well as electronic and electric parts and accessories thereof, namely, amplifiers, anodes, branch boxes, electric cables, junction sleeves for electric cables, capacitors, circuit breakers, circuit closers, electric conductors, electricity conduits, electric connections, connectors for electric circuits, electric contacts, control panels, converters, couplings, current rectifiers, electromagnetic coils, inductors, inverters, reducers, relays, sockets, plugs and other contacts for electric connections, switchboxes, electric switches, transformers, electronic transistors and wires, sold as a unit; construction elements of solar energy plants, namely, photovoltaic solar modules and solar collectors for the production of electric power; construction elements of solar energy plants, namely, solar modules and solar collectors for generating electricity; photovoltaic installation apparatus, namely, solar modules for generating electricity; solar batteries; regulating and safety accessories for solar installation systems, namely, solar thermal and electric receivers for photovoltaic installations; devices for electronic regulating and controlling of electric current, as well as electrical monitors for monitoring electric current and electric signals in solar installations, specifically, photovoltaic installations; diagnostic devices in the nature of electric sensors for solar installations, in particular for photovoltaic installations; inverters for isolated operation and parallel mains operation; electronic network feed-in devices, namely, network routers; battery chargers, electronic battery charge controllers, electronic accumulators, filling-level water meters and filling-level remote level indicators for tanks and tank farms; software for the calculation, design, simulation, valuation and control of solar-thermal and photovoltaic installations