| 摘要 |
PROBLEM TO BE SOLVED: To provide a constant current device for achieving current value setting with wide variable width and high precision. SOLUTION: This constant current device is provided with a series/parallel circuit where n pieces of series circuits having switches S and resistances R connected in series are connected in parallel; a voltage/current converting element F1 serially connected to the series/parallel circuit; and an operating amplifier OP1 with one input terminal connected to the common connection point of the series/parallel circuit and the voltage/current conversion element F1 and the other input terminal for inputting a control signal, wherein the output terminal is connected to the input terminal of the voltage/current conversion element F1. Thus, it is possible to solve the problem by a constant current device in which the rate of the resistance value of each resistance of the series circuit is 1:1/2:1/4 to 1/2<SP>n-1</SP>. COPYRIGHT: (C)2007,JPO&INPIT
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