| 摘要 |
PURPOSE:To obtain a small-sized and unified matrix switch input discriminating circuit, by providing necessary numbers of row and column signal sense circuits, and constituting said circuit by connecting a group of selecting element circuits selectively with one circuit in each group of sense circuits through a diode. CONSTITUTION:A row signal sense circuit group 17 which has a pnp transistor (TR) 5 and a detecting resistance 3 connected to a power source at one terminal and to the base resistance 16 of the TR5 and the row line input terminal 1 of a matrix switch at the other terminal, and a column signal sense circuit group 19 which has an npn TR12 and a detecting resistance 11 grounded at one terminal and connected to the base resistance 18 of the TR12 and a column line input terminal 2 at the other terminal are provided. Then, a selecting element circuit group is coupled selectively with one of the circuits 17 and 19 through a diode, and a discrimination signal for a connection between a row and a column line connection terminal corresponding to a selective connection of the matrix switch is outputted. |
