A voltmeter is given a measurement limit of 30V, an accuracy class of 0.5.

A voltmeter is given a measurement limit of 30V, an accuracy class of 0.5. Determine: the relative error for a point 5V 10V 30V, the largest absolute error of the device.

For a given voltmeter, the largest absolute error is determined by multiplying the upper measurement limit by the accuracy class divided by 100. That is,

30 * 0.5 / 100 = 0.15 V.

The relative error limit at the 5 V point is determined by dividing the largest absolute error multiplied by 100 by 5 V:

0.15 * 100/5 = 3%.

Similarly, the limits of the relative error at points 10 V and 30 V:

0.15 * 100/10 = 1.5%,

0.15 * 100/30 = 0.5%.