__________ circuit is most commonly used to measure strain with the help of a strain gauge.

ANS:B - Voltage balancing potentiometric

The circuit most commonly used to measure strain with the help of a strain gauge is the Voltage balancing potentiometric circuit. Explanation:

• Strain gauges are devices used to measure the strain (deformation) of an object under applied force.
• Strain gauges operate on the principle that the electrical resistance of a conductor changes when it is subjected to mechanical strain.
• In a voltage balancing potentiometric circuit, the strain gauge is connected in a Wheatstone bridge configuration along with precision resistors.
• The Wheatstone bridge is supplied with a constant voltage, and the output voltage across the bridge is measured.
• As the strain gauge undergoes mechanical deformation due to applied strain, its resistance changes, causing an imbalance in the Wheatstone bridge.
• The output voltage of the Wheatstone bridge is proportional to the strain-induced resistance change of the strain gauge.
• By measuring the output voltage and knowing the characteristics of the strain gauge and Wheatstone bridge, the applied strain can be determined accurately.
• This method offers high sensitivity and accuracy in strain measurement and is widely used in various applications such as structural monitoring, material testing, and industrial instrumentation.