Analog meters are so called because they do not measure the electrical characteristics directly. They do their measuring indirectly by measuring the effect of what is being measured. The effect and the amount of the effect are considered analogous to the original characteristic being measured. Usually, the current is the first characteristic tested and the effects of the current, either magnetic or thermal, are converted to movement with a deflected pointer. The greater the current being measured, the greater is the magnetic or thermal effect, and the greater the pointer deflection. The movement or distance of the pointer action, then, is analogous to the amount of current being measured.
Analog pointer meters have some built-in characteristic difficulties. These difficulties require the user to closely scrutinize and analyze the pointer reading. The numerals on the scale are usually small because of space problems. Most meters have some built-in inaccuracies, but the reading inaccuracies of the pointer and scale compound those inaccuracies. In some cases, the inaccuracies can be tolerated, but in other cases, they cannot.
Digital meters give direct readouts with the actual numerals. The numerals are large and easier to read. They are numerically specific and do not require scrutiny or interpretation to determine the reading. The built-in level of accuracy of the digital meter is not degraded by any reading or interpretation inaccuracies.
The three major test and measurement characteristics: current, voltage, and resistance, are related to each other by Ohm’s law, as taught in basic electricity. This simplifies meter design somewhat since the meter can set up circuits so that one characteristic can be used to determine the other characteristics to be measured. For example, the current can be used to indicate voltage or resistance, and vice versa. Since resistance (R) = voltage (V) divided by current (I) (R = V/ 1), if the meter uses a standard, known voltage source, then the amount of current that flows will indicate the amount of resistance that allowed that current. On the other hand, since V = IR, if the meter uses a standard, known resistance in its circuit, then the amount of current that flows will indicate the amount of voltage that caused that current flow.
Analog, or pointer meter movements rely on the effects of current flow, not only to measure current but to measure voltage and resistance using Ohm’s law. However, other meters that use built-in amplifiers usually respond to voltage as the basic measurement characteristic, again, using Ohm’s law to calculate current and resistance. This applies to both analog and digital meters with built-in amplifiers.
References
https://www.eetimes.com/author.asp?section_id=216&doc_id=1324246
https://www.circuitspecialists.com/blog/analog-and-digital-panel-meters-considerations-2/