Many handheld digital multimeters today or DMMs feature a three and a half digit displays, and three numeric characters on the right corner show values between zero and nine. Nonetheless, the leading digit, referred to as the half digit, could only be either one or zero.
Such types of digital multimeters can show numbers from zero up to 1,999. That’s the reason why they are often referred to as 2,000-count digital multimeters.
The Meaning of 6000 Counts on a Multimeter
To make everything short, 6000 counts on your digital multimeter indicate the reading capacity when you measure a 4-volt source. In that scenario, it’s the three decimal places in every measurement.
Please bear in mind that quality high-resolution handheld DMMs normally have a two thousand counts, four-and-a-half-digit display. That allows them to show values between zero and 19999. On top of that, 4000 count multimeters often have a four and three-quarters digit display, not to mention it can show values from zero to 39999.
Connecting the gap between those two are the three and three-quarters-digit display or the 4000 count digital multimeters. Remember that a number of digital multimeters will leave the leading digit black when it’s zero.
In most circumstances, the bigger the number of the counts, the greater and higher the resolution will be. Further, the higher a digital multimeter’s resolution, the higher the accuracy will be as well. Other design aspects come into action concerning the accuracy of the digital multimeter.
That involves the accuracy of the analog to digital converter, stability of internal references, component tolerance, and noise level. Hence, please do not think that a four and a half digital multimeter is ten times more accurate compared to its three and a half digit counterparts.
What’s more, digital multimeters always have automatic polarity detection. That is why they can show negative values agreeing to the range of its positive values. For instance, a three-and-a-half-digit digital multimeter will display values from zero to 1999 and values from -1999 to zero.
Understanding More about Counts on a Digital Multimeter
Imagine if a digital multimeter’s display is 2000 counts. It can show digits from 0000 to 1999 counts like a 3 ½ digit multimeter. When the display of your multimeter is 20,000 counts, it can show digits from 00000 to 1999 counts, like 4 ½ digit multimeter.
Hence, counts and digits are two unique ways to show the same thing. Counts disregard any polarity signs and decimal points.
Do Counts Influences the Accuracy of a Digital Multimeter?
Keep in mind that the count influences the accuracy of your multimeter. In case you didn’t know yet, one “count” is categorized as a unit change in the last digit of the multimeter display.
For instance, let’s say you need to measure a DC voltage: 5 volts with a digital multimeter. Measure the accuracy by referring to the DC voltage specification of your digital multimeter.
According to the datasheet, the accuracy of the 5V DC voltage is “0.02% of reading + 4 counts.”
= 0.02% of reading + 4 x resolution
= 0.02% x 5.0000V + 4 x 0.0001 V
= 0.0014 V
Total accuracy is 5.0000±0.0014 V
Introducing Digits and Resolution
Now that you finally understood what count is and what 6000 counts mean in a digital multimeter, it will help if you also learn more about digits and resolution. These two are also related to counts.
The resolution of your digital multimeter depends on the maximum number of ADC counts that happens during a complete conversion. For instance, a 2000-count multimeter along with a 3 ½ digit display has a theoretical resolution of .05%. Nonetheless, a practical resolution will also consider the number of least significant counts, more like the accuracy rating.
Normally, the DC voltage measurements take advantage of the ADC’s full-count capability, as the signal condition that uses resistive filters and dividers is not difficult. Other functions might be limited range-wise or may require signal conditioning, limiting the ADC’s input range. That then leads to a lower resolution.
On the other hand, the display digit talks about the level of resolution your digital multimeter can measure. It’s normal to notice a handheld digital multimeter with display digits of 4 ½ digits and 3 ½ digits. Also, bench digital multimeters are more likely to give display digits of 8 ½ digits, 7 ½ digits, 6 ½ digits, and 5 ½ digits.
Handheld multimeters are typically utilized for basic troubleshooting and preventive maintenance activities, which don’t need high measurement resolution. A lot of benchtops have 6 ½ and 5 ½ digits, which are suitable enough for most applications.
It’s worth mentioning as well that the 8 ½ and 7 ½ digits benchtop multimeters are considered high-performance tools, which are usually utilized for high precision applications and as reference standards for metrology laboratories.
Bear in mind that a half digit could only be a one or zero. Hence, a 3-and-a-half-digit digital multimeter provides or minus 2000 counts. On the other hand, a four and a half digit DMM provides plus or minus 20,000 counts and so on.
You see, the number of digits directly converts to the number of counts. Counts and digits offer you a basic idea of the resolution of your digital multimeter. They are not directly connected to accuracy. It’s a typical misunderstanding that counts and digits are the accuracies of a digital multimeter.
So, the next time you notice a 6 ½ digit digital multimeter, you can easily determine it to be an actual measurement range of positive or minus 1999999 or 2,000,000 resolution counts. Moreover, the one-half digit mainly refers to the most important digit but can only be either a one or a zero.
You have also learned that accuracy is how great the measurements are. For instance, how close the computed value is to the real value. Remember that resolution is the level of detail, which is measurable or the number of relevant digits on a digital multimeter.
We hope you find this guide useful and educational at the same time. Share your thoughts by leaving your comments!