THE STRAIN GAUGE
The strain gauge has been in use for many years and is the fundamental sensing element for many types of sensors, including pressure sensors, load cells, torque sensors, position sensors, etc. The majority of strain gauges are foil types, available in a wide choice of shapes and sizes to suit a variety of applications.
They consist of a pattern of resistive foil which is mounted on a backing material. They operate on the principle that as the foil is subjected to stress, the resistance of the foil changes in a defined way.
The strain gauge is connected into a Wheatstone Bridge circuit with a combination of four active gauges (full bridge), two gauges (half bridge), or, less commonly, a single gauge (quarter bridge). In the half and quarter circuits, the bridge is completed with precision resistors.
The complete Wheatstone Bridge is excited with a stabilised DC supply and with additional conditioning electronics, can be zeroed at the null point of measurement. As stress is applied to the bonded strain gauge, a resistive changes takes place and unbalances the Wheatstone Bridge. This results in a signal output, related to the stress value.
As the signal value is small, (typically a few millivolts) the signal
conditioning electronics provides amplification to increase the signal level to 5 to 10 volts, a suitable level for application to external data collection systems such as recorders or PC Data Acquistion and Analysis Systems.
Some of the many Gauge Patterns available.
Most manufacturers of strain gauges offer extensive ranges of differing patterns to suit a wide variety of applications in research and industrial projects.
They also supply all the necessary accessories including preparation materials, bonding adhesives, connections tags, cable, etc.
The bonding of strain gauges is a skill and training courses are offered by some suppliers. Click here for our TRAINING page...
There are also companies which offer bonding and calibration services, either as an in-house or on-site service.
More PRODUCT FEATURES to come... Pressure Sensors, Load Cells, Vibration Sensors, Torque Sensors, Data Acquisition, etc.
The British Society for Strain Measurement
This page is sponsored by
TML STRAIN GAUGES
Large choice of high accuracy assured types and patterns for use in transducers, stress analysis, materials and structural testing.
Bonding adhesives, coatings, terminal strips and lead wires.
Many items from stock...
Call for your FREE copy of the latest Strain Gauge catalogue and guide.
Tel: +44(0)1527 853267
for the measurement and control of
PRESSURE - PROXIMITY - DISPLACEMENT - STRESS/STRAIN - NOISE - VIBRATION - LOAD/FORCE
For more information,
visit our website at
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email your details to
Other Strain Gauge suppliers...
SMD - TMS - Sensors UK Ltd. - StrainSense Ltd. -
VIshay Measurements Group
Strain Gauge Bonding Services...
The Strain Gauging Company - PCM Ltd.
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