Analogue meter reading practice

1. Check the units and the range printed on the dial, such as 0-1 A or 0-10 V.
2. Work out what each division is worth: the gap between two numbered marks, divided by the number of divisions between them.
3. Read the needle against the scale, to the nearest half division if it lies between marks.
4. Correct for any zero error, and write down the units.

For example, on a 0-1 A scale there are 5 divisions between each 0.1 A mark, so each division is 0.02 A. A needle halfway between the 0.30 A and 0.32 A divisions reads 0.31 A.

Look straight at the needle. Viewed from the side, it appears against the wrong part of the scale, an error called parallax. Many meters have a mirror strip along the scale: when the needle hides its own reflection, you are looking from directly in front.

Before connecting the meter, check that the needle rests exactly on zero. If it doesn't, that is a zero error: subtract it if the needle sits above zero, and add its size if it sits below. The uncertainty of a single reading is usually taken as half a division.

• Assuming each division is 0.1 without checking, which is wrong for most ranges.
• Reading from the scale of the wrong range on a meter with several.
• Miscounting the divisions from the last numbered mark.
• Forgetting the zero error, or applying it the wrong way round.