Circuit and method for measuring resistance of variable resistor

A resistance and variable technology, applied in the direction of measuring resistance/reactance/impedance, measuring electrical variables, measuring devices, etc., can solve the problems of low real-time requirements, low precision requirements, short capacitor charging and discharging time, etc. Contradictory effect of measurement accuracy and measurement time
CN104897964AInactive Publication Date: 2015-09-09有朋有为科技(深圳)有限公司
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
有朋有为科技(深圳)有限公司
Publication Date
2015-09-09
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention aims to provide a circuit and a method for measuring resistance of a variable resistor. The circuit comprises single-chip microcomputers, a capacitor, a to-be-tested variable resistor Rx and a standard resistor R1. One end of the capacitor C is connected with the single-chip microcomputer GP0, and the other end of the capacitor C is connected with the ground. One end of the standard resistor R1 is connected with one end of the capacitor C, and the other end of the standard resistor R1 is connected with the single-chip microcomputer GP1. One end of the to-be-tested variable resistor Rx is connected with the single-chip microcomputer GP2, and the other end of the to-be-tested variable resistor Rx is connected with the other end of the standard resistor R1. The other end of the to-be-tested variable resistor Rx is connected with the other end of the standard resistor R1. According to the invention, a charging time T1 of a charge and discharge loop of the standard resistor R1 and the capacitor C and a charging time T2 of a charge and discharge loop between the serially-connected to-be-tested variable resistor Rx and the standard resistor R1 and the capacitor C are measured, and the resistance of the to-be-tested variable resistor Rx is calculated through a mode of Rx=R1*(T2-T1) / T1. The method provided by the invention solves the contradiction between measurement precision and measurement time in the circuit for measuring the resistance of a variable resistor by measuring the charge and discharge time of a capacitor in the prior art, and can obtain a good measurement result for a small variable resistor.
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Description

technical field

[0001] The invention relates to the field of electronic circuit measurement, in particular to a circuit and method for measuring the resistance value of a variable resistor. Background technique

[0002] The RC charging and discharging circuit is a commonly used basic circuit. According to Kirchhoff's law and advanced mathematics, when the power supply E charges the capacitor C through the resistor R, the voltage Vt on the capacitor C at any time can be calculated by the formula Vt = V0 + (Ve –V0)*[1 – exp(-t / RC)] is obtained. Where Ve is the voltage of the power supply E, and V0 is the initial voltage before the charging of the capacitor C starts. When the initial voltage of the capacitor C is 0, that is, when V0=0, the above formula can be simplified as: Vt = Ve *[1 – exp( -t / RC)] (1).

[0003] Chinese Utility Model Patent No. 201320780623.6 discloses a circuit that uses the above principle to measure the resistance of a variable resistor. The circuit dia...

Claims

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