Strain Gauge R? Strain Gauge Balance R? R? R? R? Wheatstone Bridge Output V_ IN R_ IN AD623 Wheatstone Bridge Figure 3: Amplified Wheatstone Bridge Ref V? Amplified Output Signal To LabView DAQ
The Correct Answer and Explanation is:
The amplified Wheatstone bridge circuit in the schematic is designed to measure small resistance changes, typically from strain gauges, and amplify the signal for further processing. This setup consists of four resistors forming the Wheatstone bridge, an instrumentation amplifier (AD623), and a connection to a data acquisition system.
Correct Answer: The Wheatstone bridge operates by detecting variations in resistance due to mechanical strain in the strain gauges. The bridge produces a differential voltage that is then fed into the AD623 amplifier. The gain resistor (R_G) determines the amplification factor. The amplified signal is sent to the LabView DAQ system for analysis.
Explanation The Wheatstone bridge is widely used in precision measurement applications, particularly for strain gauge systems. Its design consists of four resistors connected in a diamond configuration. Two of these resistors are strain gauges that undergo resistance changes in response to mechanical deformation. When strain is applied, the resistance values of the gauges shift, leading to an imbalance in the bridge. This imbalance generates a small differential voltage at the output terminals.
The operational amplifier AD623 is integrated into the circuit to enhance the weak signal from the Wheatstone bridge. This instrumentation amplifier is chosen due to its high input impedance and ability to provide adjustable gain via an external resistor (R_G). The input terminals of the AD623 receive the differential voltage from the Wheatstone bridge, amplify it according to the selected gain, and generate a more substantial output signal.
The amplified signal is then directed to a data acquisition system (DAQ), such as LabView, which records and processes the electrical data. This system enables real-time monitoring of strain variations, making the setup ideal for structural analysis, biomedical applications, and industrial monitoring. The use of an amplified Wheatstone bridge improves sensitivity and measurement accuracy, allowing detection of minute strain-induced resistance changes effectively.
