Editing Datanetics DC-50 series (section)

===Contact assembly===
The contact assembly in DC-50 is a sealed metal–plastic sandwich. The contact assembly is based on [[Datanetics elastic diaphragm array]], but is not a true membrane system as the contacts are strips of metal instead of traces printed onto plastic. The contacts are nonetheless the thickness of membrane sheets. The layers of the assembly are as follows:

#Stainless steel backing plate, 0.09 mm thick, with a transparent blue coating applied
#Cadmium copper alloy stationary switch contact, a strip of metal 1.37 mm wide and 0.06 mm thick; the ends are stamped with a curved cross section and tinned to form the switch terminals
#Mylar spacer membrane, 0.13 mm thick
#Movable switch contact, identical to the stationary contact but facing the opposite direction
#Mylar protective cover, 0.07 mm thick

The 1972 press release gives Kapton as the diaphragm material, while the 1974 brochure cites Mylar. The press release also gives the lifetime as 50 million, unlike the 100 million given in the brochure. Kapton appears to be the brown material used in some of the prototype contact assemblies, with Mylar being the colourless transparent material.

[[File:Datanetics DC-50 contact assembly.svg|centre]]