37 Installation, maintenance, cleaning, fixing, refitting and conversion by technicians of electric and electronic circuits and circuit boards, semi-conductors, semi-conductor elements, semiconductor elements, etched, engraved, pressed, die-cut, printed circuits and electronic assemblies and electric and electronic components, electric and electronic component connections, electric and electronic component carriers electric conductors, electrical measuring devices and monitoring devices, batteries, electric, accumulators, electric, solar collectors for electricity generation, solar modules for electricity generation, solar batteries, solar accumulators, chargers, accessories and spare parts for all of the aforesaid articles, measuring, signalling, inspecting, life-saving and teaching apparatus and instruments, apparatus and instruments for conducting, switching, transforming, accumulating, regulating or controlling electricity