Method for forming switching circuit of keyboard without generating phantom phenomenon

摘要

A method for forming a keyboard switching circuit without generating phantom phenomenon is disclosed. The method includes the steps of (1) forming a matrix of nodes with input/output terminals of the keyboard circuit; (2) selecting nodes from the matrix to define a reference diagonal line which divides the matrix into upper and lower portions; (3) selectively selecting nodes of the matrix in the upper and/or lower portions to define diagonal lines parallel to the reference line, the diagonal lines being located at different distance from the reference lines and the nodes of the diagonal lines forming no rectangle with each other; and (4) setting switches in the selected nodes. Since no rectangle can be formed among the switches, no reverse current may be caused by simultaneous actuation of three switches of a rectangle and thus effectively eliminating phantom phenomenon.