Question 6.1
What is the item shown by the arrow (Figure 1)?
Figure 1:
b) What is the principle of operation of this device?
c) Name the associated electrical circuit configuration.
College Answer
Answer: Pressure transducer
b) What is the principle of operation of this device?
Transduces pressure (via strain) to electrical resistance
c) Name the associated electrical circuit configuration.
Answer: Wheatstone bridge
Discussion
Yes, this is a Wheatstone bridge pressure transducer. The device works by transducing strain into electrical resistance. Typically, it is an arrangement of resistors where the resistance of all but one is known; the remaining resistor acts as the strain gauge. As pressure on the gauge changes, so does its resistance, and this causes a change in the current which flows though the Wheatstone bridge. Thus, pressure can be inferred from the changes in current.
This device is treated with more respect and admiration in a Required reading summary.
References
For a casual acquaintance with electrical circuits, this Wikipedia entry is enough.
For the masochist, this FRCA study document will fill in all the blanks.
Myers, Kenneth. "The investigation of peripheral arterial disease by strain gauge plethysmography." Angiology 15.7 (1964): 293-304.
Lambert, Edward H., and Earl H. Wood. "The use of a resistance wire, strain gauge manometer to measure intraarterial pressure." Experimental Biology and Medicine 64.2 (1947): 186-190.