Precision Resistors

Precision Resistors

Fixed resistors have two primary uses in strain gage circuits: shunt calibration of strain-measuring instrumentation, and bridge completion. For shunt calibration, a fixed resistor is temporarily shunted across a bridge arm to produce a known resistance change in the bridge circuit. The resulting instrument indication is then compared to the calculated strain corresponding to the resistance change. For bridgecompletion applications, a fixed resistor may be used in the adjacent arm of the bridge to complete the external halfbridge circuit when a single strain gage is connected in a quarter-bridge arrangement. In each of these applications, the accuracy of the strain measurement is affected, directly or indirectly, by the accuracy and stability of the fixed resistor(s) used in the circuit. It is important, therefore, that only precision, highstability resistors be selected for these purposes.