White Paper: Introduction to Strain and Strain Measurement

Strain Gauge & Load Cell Input Transmitters

This paper covers the topic of strain gauge & load cell input transmitters and strain and load measurement as related to Acromag strain modules and transmitters, but may be extended to other strain gauge or load cell instruments.

Strain gauges change resistance in proportion to applied forces that result from loading, torque, pressure, acceleration, and vibration. Because their change in resistance to force is very small, they often connect in a Wheatstone Bridge of four elements. You can wire a bridge with one active strain gauge and 3 resistors (quarter bridge), two active strain gauges and two resistors (half-bridge), or 4 active strain gauges (full-bridge). The number of active gauges in a bridge and how they are oriented relative to applied force will determine the bridge type, its application, and relative strain computation.