I have to do an Ohmimetro to a college assignment, but I don't know how discover the measure error of my circuit. When we buy a multimeter, the equipment has a measure error calculated by the manufacturer, how do they calculate it?
1
-
1\$\begingroup\$ In addition to your existing answers, you can get NIST Traceable Certifications for multimeters, as well. NIST maintains a set of standards. You can directly contract them, if you like. Or, you can get companies who do contract NIST periodically to keep their own equipment calibrated against drift, who can then offer such services. In all cases you will have a full certification at whatever measurement points were calibrated and will have to estimate errors in between. \$\endgroup\$– jonkCommented Apr 2, 2017 at 21:38
Add a comment
|
2 Answers
\$\begingroup\$
\$\endgroup\$
They calculate it by knowing the tolerances of all the components they used, and knowing how much each component influences the overall measurement. Then they pad that with a fudge factor to account for how the component values will change as they age between calibrations.
It isn't a simple proposition, and sometimes it's more expedient to do a Monte-Carlo simulation of the circuit that randomizes the component values and do a statistical measurement of the results.
answered Apr 2, 2017 at 14:49
\$\begingroup\$
\$\endgroup\$
1
Error of the design or error of the built circuit?
These are different things. Error of the design can be calculated as indicated in @DavidTweed's answer.
Error of the build, you need to calibrate it against a series of known resistances or using a combination of loads with an accurate voltmeter and ammeter. However, you also have to factor in temperature.
This should yield a series of graphs indicating accuracy vs resistance at set ambient temperatures.
-
\$\begingroup\$ Thank you to everybody for the answers. Where can I find detailed these topics? Is there any book or website? \$\endgroup\$– VictorOFCommented Apr 2, 2017 at 22:58