What are the methods of reducing the measurement error of the pointer multimeter?

Last Update Time: 2019-02-13 13:21:56

For the limited measuring precision of the pointer multimeter, the detection error is related to the parameters, detection methods and operating conditions of the pointer multimeter, especially the parameters, sensitivity and voltage of the pointer multimeter have great influence on the detection error. When using pointer positive multimeter to detect data, the detection error should be reduced as much as possible.

 

 1. Understanding and reducing the sensitivity of the detection error caused by the sensitivity of the pointer multimeter.

Sensitivity of the pointer multimeter means that the pointer deflects to the full scale when the voltage is detected by the pointer multimeter, the current value of the detected circuit.

 

1)Method of reducing errors caused by sensitivity.

[example 1-1] an pointer multimeter is on a 100V range, If the current value of the indicator is 50μA, the internal resistor of the meter is r = 100V/50μA = 2MΩ. The main meaning is that the DC voltage block of the multimeter is 2MΩper 1V voltage.

Therefore, the higher the sensitivity of the pointer multimeter, the smaller the shunt current and the smaller the influence on the detected circuit. Therefore, the multimeter with high sensitivity should be used in order to reduce the fixed error.

 

2) the method of understanding the sensitivity of multimeter.

On the dial of the pointer multimeter, the nominal value of the sensitivity of the meter is generally marked. For example, the sensitivity of the AC voltage block and the DC 2.5kV block of the MF500 type pointer multimeter is 4 000Ω/V, and the rest of the DC block is 20000Ω/V. Thus the corresponding total resistor values of each voltage block can be calculated in order to understand the influence of the multimeter on the detected circuit.

 

2. Methods for understanding and reducing the detection errors of pointer multimeters caused by voltage drop.

The voltage drop in the detection of an pointer multimeter refers to the voltage drop produced when the DC current of the pointer multimeter is blocked in the full range detection.

First, the specific value of the voltage drop.

For a certain type of pointer multimeter, the value of voltage is usually a certain value. The voltage of different type of pointer multimeter is not different. For example, the voltage of MF500 multimeter and MF30 multimeter is about 0.75 V.

Second, the method of reducing the error caused by voltage.

In order to reduce the detection error caused by voltage, it is necessary to select the correct measuring range in addition to the high sensitivity pointer multimeter in parameter detection. For example, choosing a high voltage shield has less influence on the detected circuit than using a low voltage shield, and selecting a large current shield has less effect on the detection of a small current shield than selecting a small current shield.

 

3. methods to reduce errors in DC voltage detection.

 First, the method of reducing the error in DC voltage detection. When the DC voltage is detected by using an exponential multimeter, the internal resistor should be measured at a position far larger than the value of the resistor of the detected circuit, otherwise the detection error will be larger.

 Second, principle analysis. This is mainly because the total internal resistor of the DC voltage block of the pointer multimeter varies with the voltage range, the resistance of the low voltage shift is smaller, and the resistance of the high voltage shift is larger.

 

 

This article is from Allicdata Electronics Limited. Reprinted need to indicate the source.