tel  +39 011 220 31 20  fax  +39 011 220 32 12 MATERIALS AND FINISHES OF THE KEYBOARDS Insulators: POLYESTER FILM : all parts of 1T - 3T keyboards. ACRYLIC ADHESIVE: for coupling the parts of all keboard's model. EPOXIGLASS LAMINATE: circuit plate of keyboards 2T - 4T. GLASS: circuit plate of keyboards 2T. PHENOLIC LAMINATE: circuit plates 2T - 4T. POLYCARBONATE FILM: graphic layers of all keyboards (optionally polyester). 10µm EPOXY INSULATING VARNISH: protective coating of tracks, all models. Conductors: 10µm SILVER BASE VARNISH: the silk screend tracks of types 1T - 2T. 35µm LAMINATE COPPER: the tracks of keyboards 3T - 4T. 100µm STAINLESS STEEL BAND: contact snap domes. Finishings: 10µm GRAPHITE BASE VARNISH: conductive coating on tracks 1T - 2T (optional). GOLD PLATING 0.5µm cobalt-gold on 4µm nickel (optional) or 15µm TIN PLATING (standard) on tracks 3T - 4T.     ELECTRICAL AND MECHANICAL SPECIFICATIONS Silk screened circuit keyboards Silver tracks are 10µm thick and 1mm wide (average). Contact resistance 0,1 ohms. Track resistance (1 mm wide) 0,5 ohms x cm. Example: pin to pin key circuit = 20 cm R = 10,1 ohm Current ratings (the values are calculated with a 0.5volt falldown, measured pin to pin of an average key's circuit): keyboard surface 1 key's circuit average lenght pin to pin 1 key's circuit aver. resistance pin to pin operating current square dm cm ohm mA 1 30 15 33 2 34 17 29 4 40 20 25 10 84 42 11 Minumum insulation voltage between near tracks (polyester base): > 800Vac 50Hz Minimum insulation resistance between near tracks (polyester base): >1010ohm Actuation force: 100/ 500gr Switching travel: 0,2 / 0,6 mm Contact bounce: <10milliseconds Operating temperature: -25° / +70°C Life expectancy (current rating = 0.1 max value) >106 operations    Printed circuit keyboards Copper tracks are 35µm thick + 5µm 99% Sn + 1% Ag standard finishing and 1mm wide (average) Contact resistance 6 mohms. Tracks resistance (1 mm wide) 10 mohms x cm. Example: pin to pin key's circuit lenght = 20 cm R = 206mohms Current ratings (the values are calculated with a 0.5volts falldown measured pin to pin of an average key's circuit): keyboard surface 1 key's circuit average length pin to pin 1 key's circuit aver. resistance pin to pin operating current square dm cm mohm mA 1 10 106 4700 2 14 146 3400 4 20 206 2400 10 32 326 1500 Minimum nsulation voltage between near tracks (FR4 epoxyglass base): >900Vac 50Hz Minimum insulation resistance between near tracks (FR4 epoxyglass base): >20 x 109ohm Actuation force: 100/ 500gr Switch spacing: 0,2 / 0,6 mm Contact bounce: <10milliseconds Operating temperature: -25° / +70°C Life expectancy (current rating = 0.1 max value) >2x106 operations