National Physical Laboratory

Calibration of Resistance Bridges

NPL is now able to offer calibration of resistance bridges of all types. Resistance bridges are crucial to measuring platinum resistance thermometers with very low uncertainties – but they often operate for many years without having their own performance checked.

Isotech automatic resistance bridge calibrator (Image provided by Isothermal Technology Ltd)
Isotech automatic resistance bridge calibrator
(Image provided by Isothermal Technology Ltd)

Resistance bridges generally perform a measurement of the ratio of the resistance of a thermometer and a reference standard. This process assumes that the linearity of the electrical response is constant over the full range of resistances which may be used. This is not always the case, and must be monitored, if the measurement uncertainty is to be correctly accounted for.

Using a resistance bridge calibrator (RBC), the ratio indicated by the bridge can be validated at 35 distinct ratios to yield a check on the linearity of the bridge. By reversing the terminals, validation at a further 35 complementary ratios can be provided, giving a total of 70 distinct ratios, as well as a full calibration with an uncertainty of the order of tens of parts per billion of bridge ratio. Direct reading bridges can also be calibrated.

If you are interested in more details, or wish to ask for a quote, please get in touch.

Contact

Customer Services tel: +44 20 8943 6315
E-mail: temperature_enquiries@npl.co.uk

Last Updated: 9 Dec 2016
Created: 7 Jun 2016

Registration

Please note that the information will not be divulged to third parties, or used without your permission

Login