Glossary · Sensors and measurement
Strain gauge
Also known as: Strain gage, DMS
German: Dehnungsmessstreifen
In measurement technology, a strain gauge is a sensing element whose electrical resistance changes when it is stretched or compressed; bonded to a component, it measures the strain of the surface, usually in a Wheatstone bridge circuit.
- Sensors
In one sentence
A strain gauge changes its electrical resistance when stretched or compressed and measures surface strain, the basis of many force sensors.
Example
Strain gauges bonded to the frame of a press measure its deflection so the controller can monitor the pressing force.
How it applies
- Engineering: Strain gauges are the sensing element of most load cells, force and torque sensors and many pressure sensors. The small resistance changes require bridge circuits, excitation and amplification.
- Installation: Bonding strain gauges directly to machine parts requires surface preparation, suitable adhesive and protection; the quality of installation determines the quality of the measurement.
- Temperature: Temperature changes cause apparent strain. Bridge configurations and matched gauges compensate for this.
- Documentation: Record gauge type, gauge factor, bridge configuration and amplifier settings. For bonded measuring points, document position and orientation with photos or drawings.
Strain gauge vs. load cell
A strain gauge is a sensing element. A Load cell is a complete, calibrated sensor that uses strain gauges on a designed elastic body.