| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable resistance device whose resistance value can be changed continuously over a wide range and which is operated readily, and also to provide its operating method. SOLUTION: The resistance value of a continuous variable resistance 2 is adjusted by the voltage Vc of a variable voltage source 22 by using both a stepped variable resistance 1 and the continuous variable resistance 2 at the same time. If the voltage Vc deviates from the range of fixed voltage Vcmax-s to fixed voltage Vcmin+s, it is detected by comparators 31, 32. Choppers 33, 34 generate pulse and thereby a count value of a counter 35 is counted up or down. Accordingly, a switch in "on" among switches S1 to S(n+1) of the stepped variable resistance 1 is switched. After all the resistances pass a desired value, the voltage Vc is set in the range of a fixed voltage Vcmas-s to fixed voltage Vcmin+s, and all the resistances are adjusted to a desired value. COPYRIGHT: (C)2006,JPO&NCIPI
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