Calibration of bridge standards for use in strain-gage measurements

This article describes the method used for accuracy tests made on the BN 100 Bridge Calibration Unit.

Within the field of stress analysis the signal provided by the measuring element, usually a strain gage bridge, is normally at a low level not exceeding a few millivolts. This signal must therefore be amplified with a calibrated amplifier before it can be recorded. A common method of calibrating the amplifier system prior to using it for measurement is to substitute the strain gage bridge with a bridge standard which supplies an accurate signal. Obviously the accuracy of the bridge standard itself is a critical feature in the whole process.