An Introduction to the Resolution of the Digital Multimeter
Resolution refers to how well a watch measures. Knowing the resolution of a watch tells you whether you can see small changes in the signal being measured. For example, if a digital multimeter has a resolution of 1mV in the 4V range, then when measuring a 1V signal, you can see a tiny change of 1mV (1/1000th of a volt).
If you're measuring less than 1/4 inch (or 1 mm), you definitely don't want to use a ruler that measures inches (or centimeters). If the temperature is 98.6°F, it is useless to measure it with a thermometer that only has whole-number markings. You will need a thermometer with a resolution of 0.1°F.
The number of digits and words are used to describe the resolution of the table. Digital multimeters are classified by the number of digits and words they can display.
A 3-and-a-half-digit table can display three full digits from 0 to 9, and one half-digit (only 1 or no display). A 3.5-digit digital meter can achieve a resolution of 1999 words. A 4.5-digit digital meter can achieve a resolution of 19,999 words.
It is better to describe the resolution of digital tables with words than with bits. The resolution of three-and-a-half-digit digital tables has been increased to 3200 or 4000 words.
The 3200-word digital meter provides better resolution for certain measurements. For example, with a 1999-word meter, you cannot display 0.1V when measuring a voltage greater than 200V. However, a 3200-word digital meter can still display 0.1V when measuring a voltage of 320 volts. When the measured voltage is higher than 320V and the resolution of 0.1V is to be achieved, a more expensive 20,000-word digital meter must be used.
