... early 1980.1)Items——membrane switch, keypad, membrane keypad, keyboard switch, switch panel, membrane panel, membrane overlay, membrane ... ——35V DC, 100mA, 1Wb) Contact resistance——10 - 500Ωc) Insulation resistance——100mΩ at 100V DCd) Dielectric withstand——250V ... Operating temperature—— -40°C ~ +80°Cl) Storage temperature—— -40°C ~ +85°Cm) Humidity——90% - 95% (40°C) for 240hrs9)Thickness——between ...