A keyboard has a base 10 having a membrane structure in which foil layers having contact points are separated. The top one is moved when a domed section 5 on a flexible membrane 2 is displaced by key 8 operation. The underside of the keys are formed to receive the ends of a linkage mechanism 6,7. The end of one link 7B is fixed while the other is free to move in a slot 8B. The lower ends of the links similarly have one fixed and one movable support point 6D,7C in the housing. As the key returns to the at rest position the end of the movement has increased friction.
