Vernier Tech Info Library TIL #1230

Question

What is the accuracy of a DVP-BTA voltage probe?

Answer

It is always a bit tricky to state an accuracy figure, since it depends on what the sensor is connected to and how it has been calibrated.

Assuming you are using DVP-BTA connected to a LabPro or LabQuest, the first number to look at is resolution, which is the smallest increment in voltage that can be measured. For DVP-BTA, this is 0.003 volts. The accuracy depends on how the sensor was calibrated and, to some small extent, the LabPro used.

As part of our manufacturing process, the DVP-BTAs are made with precision resistors and instrumentation amplifiers, so they are quite standardized and checked against a known set of voltages. If the voltage is off by 0.1 volts or more, it is rejected. There is no calibration done because this particular sensor does not have a way to "store" the calibration. (Most of our sensors do have on-sensor storage of calibration).

You can calibrate the sensor, and save the calibration on your computer or LabQuest to improve the accuracy. Just do a standard calibration two-point calibration using shorted leads as 0 volts and a known voltage (measured with a good voltmeter) as another.

As shipped, with no local calibration, the accuracy is something like 0.1 volts, but by calibrating, you can make the accuracy very close to 0.01 volts.

Created by: dvernier on October 22 2003
Last updated by: jhopkins on July 14 2009