Voltage measuring device

Abstract

The invention relates to a voltage measuring device. According to the voltage measuring device, a first stepping panel is constituted by a measuring panel and two bracket panels without welding resistors; a second stepping panel consists of a measuring panel and a bracket panel, the measuring panel is constituted by an annular resistor network of 9*9 omega and two 1-omega resistors, and the bracket panel is constituted by ten 0.5-omega resistors; a third stepping panel is constituted by a measuring panel of 10*1 omega and a replacing panel; all contact points of a fourth stepping panel are connected with corresponding contact points on the measuring panel of the third stepping panel an 800-omega resistor, a 7200-omega resistor and a resistor measuring network are in parallel connection with one another in a circuit for range switching, and the minimal resolution ratio reaches 1 [mu]V; the measuring panels are connected with one another through wires. According to the voltage measuring device, switching is realized not through a switch, so that when the voltage measuring device is used for measuring, the influence of variation and thermoelectric potential can be avoided.

Description

technical field [0001] The invention relates to an instrument for measuring DC voltage. Background technique [0002] At present, for a potentiometer with four measuring discs, the connection between the four measuring discs is generally switched by a switch in the middle disc, which will cause a change in contact resistance and limit the resolution. In order to overcome this problem, a large electric brush is generally used to increase the contact area, and a silver-copper composite material is used; the application number 200510062260.2 discloses a new method for solving the deterioration of the switch contact resistance by a potentiometer with four measuring discs. The first and second stepping discs are composed of a measuring disc and a replacement disc. The resistance values ​​on the measuring disc and the substituting disc are the same. Every time a resistance is added to the measuring disc, the substituting disc will reduce the same resistance. 3. The fourth steppin...

AI Technical Summary

Problems solved by technology

The four measuring discs are connected between the two measuring terminals, so that the brush on the stepping disc switch is excluded from the measuring circuit, and there is no switching between the resistances on the four measuring discs, so there is no variation; Since the potentiometer step disc switch rotates at an angle of 15° for each step, 24 contacts can be distributed on each layer. There are resistances on each layer, and the inner layer’s resistance is out of tolerance, which will cause inconvenience to maintenance. The fourth stepping plate has half layers of measuring plate, replacement plate and auxiliary plate. The stepping plate switch also needs two layers inside and outside, and the inner layer also has resistance. Maintenance is also inconvenient

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