Micro-electric potential measurement instrument

Abstract

The invention discloses a micro-electric potential measurement instrument provided with four stepping plates and used for DC (Direct Current) voltage measurement. The micro-electric potential measurement instrument has two measuring ranges; each stepping plate is composed of a measuring plate and a replacing plate having the same structure as the measuring plate; a resistor is welded between contacts of both the measuring plate and the replacing plate on the first stepping plate, and no resistor exists on the rest stepping plates. According to the micro-electric potential measurement instrument, resistance of leads inside the micro-electric potential measurement instrument, contact resistance and variation of a switch, and an influence from thermoelectric potential to the instrument can be ignored.

Description

technical field [0001] The invention relates to an instrument for measuring DC voltage. Background technique [0002] At present, for a micropotential measuring instrument with four stepping disks, the intermediate disk generally uses a switch for the connection between the four stepping disks, which will cause a change in contact resistance and limit the resolution. In order to overcome this problem, large electric brushes are generally used to increase the contact area, and silver-copper composite materials are used; application number 200810120441. method, its four stepping discs are composed of measuring discs and substituting discs, excluding auxiliary discs, each measuring disc and substituting discs have resistance, and the measuring discs and substituting discs on its four stepping discs are Changing the disc constitutes a bridge circuit in the circuit. Its biggest problem is that the error is not independent. Once the indication value of a certain point of the meas...

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Problems solved by technology

[0002] At present, for the micropotential measuring instrument with four stepping disks, in the connection between the four stepping disks, the intermediate disk generally adopts switch switching, which will cause the deterioration of the contact resistance and limit the resolution.

In order to overcome this problem, large electric brushes are generally used to increase the contact area, and silver-copper composite materials are used; application number 200810120441. method, its four stepping discs are composed of measuring discs and substituting discs, without auxiliary discs, each measuring disc and substituting discs have resistances, and the measuring discs and substituting discs on its four stepping discs are Changing discs constitutes a bridge circuit in the circuit. Its biggest problem is that the errors are not independent. Once the indication value of a certain point of the measuring disc is out of tolerance, it is impossible to determine which resistance is caused by the out-of-tolerance, which brings inconvenience to identification and maintenance.

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