1/2 Bridge
Measurements
In a
1
⁄
2
bridge arrangement, there are two active elements (gages) within the
Wheatstone Bridge circuit (Figure 4-9). The
1
⁄
2
bridge arrangement has
twice the sensitivity as the
1
⁄
4
bridge arrangement and the additional strain
gage compensates for temperature induced apparent strain. The
1
⁄
2
bridge
strain measurements available based on gage positioning on the specimen
are described in the following sections.
Bending 1/2 Bridge
(HBENding)
The maximum sensitivity achieved with a
1
⁄
2
bridge arrangement is when
the strain gages are mounted to the specimen as indicated in Figure 4-10.
When the beam is strained, strain gage Rg1 will be strained in tension and
strain gage Rg2 will be strained in compression. When both gages are
strained the same amount simultaneously, the output of the bridge
(sensitivity) is doubled. Since the gages represent adjacent legs in the
Wheatstone Bridge circuit, any temperature induced strain is cancelled.
Figure 4-9. 1/2 Bridge Arrangement
Figure 4-10. Bending 1/2 Bridge
Chapter 4
Understanding the Strain Gage Multiplexers 59
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