Desk-top calculator keyboard switch

A key input assembly for use in miniature electronic apparatus comprising:

• first contact means formed of an electrically conductive material containing carbon particles, said first contact means including a plurality of contacts arranged separately from each other so as to form a matrix;
• second contact means including a first electrically conductive layer formed of conductive paint containing silver particles, a second conductive layer of electrically conductive material containing carbon particles overlying portions of a surface of said first layer for making electrical contact with said first contact means, and an insulating layer for covering those portions of the surface of said first layer which are not overlaid with said second layer;
• and
• means for making an electrical contact between said first and second contact means;
• the portions of said first layer which are overlaid with said second layer of said second contact means being formed as pairs of contacts, the remaining portions of said first layer, which are covered with said insulating layer, including wiring conductors associated with the pair of contacts.