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Megohmmeter accuracy

time:2020/6/4   source:华天电力  reading:341 time

It is important to use megometers to provide correct measurements. Knowing what these measures mean is even more important. Accuracy and precision ensure that the measurements you make will be useful; Higher accuracy leads to easier repeatability, and higher accuracy means your readings will be closer to perfection.


What is the accuracy of the digital megohm meter?


Accuracy is the maximum allowable error in a given operating condition, expressed as a percentage of how close the displayed measurement is to the actual (standard) value of the measured signal, and the accuracy needs to be compared with accepted industry standards.


The accuracy of a particular digital megohm meter is important, depending on the application. For example, most AC power lines range in voltage from ± 5% to more. An example of this change is voltage measurements made in a standard 115V AC socket. If only a digital megometer is used to check whether the socket is energized, a digital megometer with a measurement accuracy of ± 3% is suitable.


Some applications, such as automotive, medical aviation, or dedicated industrial equipment calibration, may require higher accuracy, ranging from 98.0 V to 102.0V on digital megabytes with an accuracy reading of 100.0 V ± 2%. This may be fine for some applications, but it is not acceptable for more sensitive electronic devices.


Precision can also include the number of specified digits (counts) added to the base precision level. For example, an accuracy of ± (2% + 2) means that a 100.0V reading on a Megabyte can range from 97.8V to 102.2V. Many applications can be realized by using digital megohm meters with higher accuracy.


Fluke handheld digital megohm meter has a basic DC accuracy range of 0.5% to 0.025%.


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How accurate is the digital megohm meter?


Precision is the ability of exponential megohm meters to provide the same measurements over and over again.


A common example used to explain accuracy is the arrangement of holes on a range target. This example assumes that a rifle aims at the center of the target and fires from the same position each time.


If the hole is tightly packed but outside the bullseye, the rifle (or shooter) may be considered accurate but not accurate.


The rifle is accurate and precise if the hole is tightly tucked into the bull's eye. If the holes are randomly distributed over the entire target, it is neither accurate nor precise (nor repeatable).


In some cases, accuracy or repeatability is more important than accuracy. If measurements are repeatable, error patterns can be identified and compensated for.


What does measuring resolution mean?


Resolution is the smallest increment a tool can detect and display.


For the non-electrical example, consider two rulers. The resolution of the 1/16-inch shadowmark is higher than that of the quarter-inch shadowmark.


Imagine a simple test of a 1.5V household battery. If the resolution of a digital megometer is 1 mV in the 3 V range, you may see a 1 mV change when reading the voltage. Users can see changes as small as one thousandth of a volt, or as small as 0.001 over a 3 V range.


The resolution may be listed as the maximum resolution in the meter's specification, which is the minimum identifiable in the meter's minimum range setting.


For example, a maximum resolution of 100 mV (0.1 V) means that when the megometer range is set to measure the highest possible voltage, the voltage will display to the nearest tenth of a volt.


As long as the measured value is within the set range, the resolution can be improved by reducing the range setting of the digital megohm.


What is the range of a megometer?


The range and resolution of a digital megohm are related and are sometimes specified in the specification of a digital megohm.


Many megometers provide an automatic range feature that automatically selects the appropriate range for the range to be measured. This provides both a meaningful reading and the best resolution for the measurement.


If the measured value is higher than the set range, the Megabyte displays OL (overload), obtaining the most accurate measurement at the lowest possible range setting without overloading the Megabyte.


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