The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 19, 1991
Filed:
Jan. 31, 1989
Soichiro Yasunaga, Kawasaki, JP;
Riken Denshi Co., Ltd., Kawasaki, JP;
Abstract
A potentiometer used with a voltmeter has an impedance transformer to which a voltage to be measured is applied, a bank of resistors acting collectively as a variable resistor and having switches connected in parallel across the respective resistors of the bank, a switch control circuit, and a multiplier-setting circuit, all connected in series. The resistors have resistances r, 2r, 4r, 8r, . . . , 2.sup.n-1 r or 10.sup.0 (r, 2r, 4r, 8r), 10.sup.1 (r, 2r, 4r, 8r), . . . , 10.sup.n-1 (r, 2r, 4r, 8r), where r is a minimum, or unit, resistance value. The unit resistance value r multiplied by a multiplier N of two or more digits is equal to the resistance value of the variable resistor bank. This multiplier N expressed in decimal notation is set by means of a multiplier-setting circuit, which causes the switch control circuit to selectively open the switches, thereby adjusting the resistance value of the variable resistor bank according to the value of N so that the output voltage of the bank equals the full-scale voltage of the voltmeter, at which condition the value of N coincides with the magnitude of the voltage to be measured, provided the latter is not less than the full-scale voltage of the voltmeter, in which event an error indication is given.