Quantity indicators; phototelegraphy apparatus; signal lights; electro-dynamic apparatus for the remote control of signals; loudspeakers; voltage stabilizers for electrical measure; electric measuring instruments; electric wires; resistance wires; printed circuits; electric coils; variometers; electric converters; ferrite cores for electric converters; electric light dimmers; electric switches; current rectifiers; lighting ballasts; voltage stabilizing power supply; current rectifying apparatus; lightning arresters; electroplating machines; electronic burglar alarms; battery chargers; electric door closers