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Ammeter And Voltmeter Measurement Mechanism Is Basically The Same
Jul 07, 2017

  Ammeter and voltmeter measurement mechanism is basically the same, but the connection in the measurement line is different. Therefore, voltmeter in the selection and use of ammeter and voltmeter should pay attention to the following points.

  1, type of choice. When the measurement is DC, should be selected DC table, that is, magnetic measurement system of the instrument. When the measurement is AC, pay attention to its waveform and frequency. If the sine wave, just measure the rms value can be converted to other values (such as the maximum, the average, etc.), using any kind of AC table can be; voltmeter if non-sine wave, it is necessary to distinguish what is measured Value, effective value can be selected magnetic or ferromagnetic electric system measuring instrument of the instrument, the average value of the rectifier system is used to measure the instrument. Electric measuring instruments are often used for precision measurement of AC current and voltage.

  2, the choice of accuracy. The higher the accuracy of the instrument, the more expensive, maintenance is more difficult. Moreover, if other conditions with improper, and then high degree of accuracy of the instrument, it may not be able to get accurate measurement results. Therefore, in the selection of accurate accuracy of the instrument can meet the measurement requirements of the circumstances, do not use high-precision instrument. Usually 0.1 and 0.2 meter as a standard table selection; 0.5 and 1.0 level instrument used as a laboratory measurement; 1.5 below the instrument is generally used as engineering measurement selection.

  3, the range of choice. To give full play to the role of instrument accuracy, but also must be measured according to the size of a reasonable choice of instrument limit, such as improper selection, the measurement error will be great. Generally, the instrument is more than 1/2 ~ 2/3 of the maximum range of the instrument, and can not exceed its maximum range.

  4, the choice of resistance. Select the instrument, it should be based on the size of the measured impedance to select the instrument's internal resistance, otherwise it will bring a larger measurement error. Due to the size of the resistance to reflect the power consumption of the instrument itself, so the measurement of current, should use the internal resistance as small as possible ammeter; measured voltage, should use the internal resistance as large as possible voltmeter.