Quarter-Bridge I - Measurement Computing IOtech 6224 User Manual

Quarter-Bridge I

Quarter-bridge type I measures either axial or bending strain.
Quarter-bridge type I has the following characteristics:
A single active strain-gauge element is mounted in the principle direction of axial or bending strain.
A passive quarter-bridge completion resistor (dummy resistor) is required in addition to half-bridge completion.
Temperature variation in specimen decreases the accuracy of the measurements.
Sensitivity at 1000
The following symbols apply to the above circuit diagram and to the equations provided in the supplemental information.
R1 and R2 are the half-bridge completion resistors.
R3 is the quarter-bridge completion resistor (dummy resistor).
R4 is the active strain-gauge element measuring tensile strain (+ ).
Supplemental Information
Data from strain channels (Quarter-Bridge I) is converted to strain units using the following equation:
4 V r
6
10
GF 1 2 V r
6224 User's Manual
is ~ 0.5 mV / V input.
out EX
R L
1
R g
Strain and Pressure/Force 7-3