Voltage measuring instrument with multiple range

Abstract

A multi-range voltage measuring instrument includes a first stepping panel composed of a measuring panel having 21x100 ohm and bracket panel I' and I'' without resistance, a second stepping panel comprising a measuring panel formed of a resistance ring of 9x90 ohm and two 10 ohm resistances, a bracket panel formed by a 10x5 ohm, a third stepping panel comprising of a measuring panel of 10x10 ohm and a substitution panel. Each contact of the forth stepping panel is connected with the corresponding contact of the measuring panel of the third stepping panel, and the measuring panels are connected by conductors without on-off switch, which is capable of ignoring variation and thermal potential effect when measuring by voltage measuring instrument. The voltage measuring instrument with the maximum measuring voltage of 2.31V and the minimum resolution of 0.1 muV is provided with four ranges of x10, x1, x0.1, x0.01.

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, large electric brushes are generally used to increase the contact area, and silver-copper composite materials are used; application number 200510062369.6 discloses a new method for solving the deterioration of 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 stepping disc ...

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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