How to read an analog ammeter or voltmeter
- Find full scale: the last figure, or the terminal the lead is on if the meter has two.
- Work out one small division: the gap between two numbered marks divided by the divisions between them.
- Count divisions from the nearest numbered mark and read to the nearest half division.
- Check the zero first. If the pointer does not rest on 0, take the zero error off: corrected reading = reading − zero error.
- Look straight down at the needle, so it hides its reflection in the mirror strip.
An example
In set KR7222 the lead is on the 15 V terminal of a 3 V and 15 V voltmeter. Thirty small divisions span 0 to 15 V, so one division is 0.5 V, and the needle is on 13 V. In the second question a 0 to 5 A ammeter rests at −0.1 A with the switch open and reads 0.9 A with it closed: 0.9 − (−0.1) = 1 A. Open set KR7222
Multimeter scales, the ohms scale and range picking are on the analog multimeter reading practice page.
Questions
How do you find the value of one small division?
Take two numbered marks next to each other, subtract, and divide by the number of small divisions between them. From 0.2 A to 0.4 A with 10 divisions between, one division is 0.02 A. Read to the nearest half division.
What is zero error on an ammeter or voltmeter?
With no current, the pointer should rest on 0. If it rests on another mark, that is the zero error. To the right of 0 it is positive, to the left negative. Take it off every reading: corrected reading = reading − zero error.
How do I correct a negative zero error?
Subtract it, minding the sign. A pointer resting at −0.1 A that then reads 0.9 A gives 0.9 − (−0.1) = 1.0 A. A negative zero error makes every reading too low, so the correction adds.
How do you read a meter with two ranges?
Check which terminal the lead is on. On a voltmeter with 3 V and 15 V terminals, the 15 V terminal means the needle at the right-hand end is 15 V, so read the 0 to 15 figures and ignore the other row.
What is parallax error and how do you avoid it?
Parallax is reading the needle from the side, so it seems to point at the wrong mark. Look straight down. On a meter with a mirror strip, move your head until the needle hides its own reflection.
Sources, read October 26, 2026: DGT Electrician curriculum, NSQF level 5, revised 2017 (PDF): MC ammeters 0 to 500 mA and 0 to 5 A; NIMI Electrician trade practical, semester 1 (PDF): the value of each major and minor division, and avoiding parallax with the mirror. The meters drawn here are our own practice faces.