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What does it mean for a DMM to have 3.5 digits? How much more accurate is a 5.5 digit multimeter versus a 4.75 digit meter? Many people assume that more digits mean more accuracy. However, these numbers express the precision of the meter, not its accuracy! In this video, learn about a DMM's accuracy, what does "half a digit" mean.
People use "accuracy" and "precision" interchangeably. They do have specific meanings, specifically with test equipment. Accuracy is how well an instrument can measure a signal, while precision is how well it can display it. Typically accuracy is affected by how much noise the equipment adds to the measurement. Precision is obvious with digital displays because it involves the number of digits. This difference is essential when looking at multimeters. Many DMMs proudly talk about how many digits they have or how many counts they display. However, these specs do not always reflect the accuracy of the DMM. Accuracy depends on the analog components like the filters and dividers that sit in front of the analog-to-digital converter.
Supplemental Content:
- Workbench Wednesday 11: Instrument Basics:Digital Multimeters
- Choosing a budget Digital Multimeter (DMM)
Bill of Material:
| Product Name | Manufacturer | Quantity | Buy KitBuy Kit |
|---|---|---|---|
| MP730028 US Bench DMM, 5.5 Digits | Multicomp Pro | 1 | Buy NowBuy Now |
| Handheld DMM 3.5 Digits (72-7780) | Tenma | 1 | Buy NowBuy Now |
| MP7300256 Handheld DMM 3.75 Digits with Bluetooth | Multicomp Pro | 1 | Buy NowBuy Now |
