The same multimeter is capable of displaying up to However, if you require more resolution in your results, eg. A 20, count will work here. Do not get confused between a larger count for display resolution, and the accuracy of the multimeter. They are two different characteristics. One gives the measurement accuracy of the multimeter see Understanding Terms - Accuracy for more info.
The other count is the ability to display this accuracy to the user. If the specification of the multimeter gives digits rather that count, it will be the number of digits that can be displayed from plus the most significant digit, which cannot be displayed right through to 9.
The fraction is used to describe how high the most significant digit in each range can go. This actual figure will change between manufacturers. For example. Note that this is the same as a count.
Common question! So, with a count the circuitry in each range gets to its limit at and has to change range. Sometimes it is important to know when the multimeter actually changes range.
If you are measuring a quantity that requires a certain amount of significant figures, but what you are measuring is on the border of when the multimeter changes range, then the resolution required could down grade by a factor of 10 right near the point of measurement and you lose the required lowest significant figure.
Thus, this multimeter may actually not be suitable. Again, it is important to understand what you are testing, and the range you will be testing in. Close search. Multimeters Clamp Meters expand. Understanding Terms - Count, Range and Resolution. However, DMM accuracy also depends on other design factors, such as Analogue to Digital Converter ADC accuracy, component tolerances, noise level, and the stability of internal references.
In addition, since DMMs have automatic polarity detection, they display negative values equal in range to the positive values. Alternatively, how close the measurement is to the actual or reference value of the signal being measured. Accuracy may be represented as a percentage as well as digits. Accuracy is generally compared to an accepted industry standard.
Component aging, battery condition, temperature and warm-up time may all affect repeatability. The smallest increment an instrument can detect and display such as hundredths, thousandths, millionths.
The upper and lower limits an instrument can measure a value or signal such as amps, volts and ohms. The larger number of counts should translate into higher resolution and generally a higher accuracy. Enquiries : www. Follow us on linkedin. Editor Gregg Cocking Email: sparks crown. Advertising Manager Carin Hannay Email: carinh crown.
About Us Advertise Contact. The display digits refer to the level of resolution that the DMM can measure. Resolution is the level of detail that is quantifiable on a DMM. Handheld DMMs are normally used for simple troubleshooting and preventive maintenance work that does not require high measurement resolution. Why is it important to understand the half digit and what does the total number of digits represent? Well yes, it is certainly important as the number of digits is almost always the first spec you will notice about a DMM.
Table 2 shows you how the DMM display digits correspond to the resolution counts. If you have a 3 and a half digit DMM, the half digit is the most significant digit. The half digit can only be a 0 or 1. So a 3 and a half digit DMM offers plus or minus 2, counts.
A 4 and a half digit DMM offers plus or minus 20, counts and so on. The number of digits directly translate to the number of counts. Digits and counts give us an idea of the resolution of a DMM. They are not directly related to accuracy. It is a common misconception that digits and counts are the accuracies of a DMM. Accuracy and resolution are one of the key specifications to consider when choosing the right digital multimeter DMM for your measurements.
Figure 3 shows how accuracy relates to the resolution on a measurement scale.
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