Concept Questions: 2-11 (10pts) : Developed initially by Samuel Christie in 1833 as an accurate ohmmeter for measuring resistance, the Wheatstone bridge subsequently was popularized by Sir Charles Wheatstone, who used it in a variety of practical applications. Today, the Wheatstone circuit is integral to numerous sensing devices, including strain –bridge gauges, force and torque sensors, and inertial gyros. 2-12 (10pts) : The absence of current flow between nodes 1 and 2, called the balances condition, implies that V1 = V2. Rx = (R2/R1) * R3 Balanced Condition 2-16 (10pts) : They are placed at the base of cantilevers and other deflecting structures to amplify the signal. We can do so electronically by feeding Vout into a high-gain amplifier, or we can amplify the mechanical pressure itself before applying it to the piezoresistor. The latter approach can be realized by constructing the piezoresistor into a cantilever structure. Deflection of the cantilever tip induces stress at the base of the cantilever near the attachment point. If properly designed, the cantilever can amplify the applied stress by several orders of magnitude. Exercises: 2-11 (15pts) : 2-12 (15pts) : Problems: 2.60 (20pts) : 2.62 (20pts) :
Concept Questions: 2-11 (10pts) : Developed initially by Samuel Christie in 1833 as an accurate ohmmeter for measuring resistance, the Wheatstone bridge subsequently was popularized by Sir Charles Wheatstone, who used it in a variety of practical applications. Today, the Wheatstone –bridge circuit is integral to numerous sensing devices, including strain gauges, force and torque sensors, and inertial gyros. 2-12 (10pts) : The absence of current flow between nodes 1 and 2, called the balances condition, implies that V1 = V2. Rx = (R2/R1) * R3 Balanced Condition 2-16 (10pts) : They are placed at the base of cantilevers and other deflecting structures to amplify the signal. We can do so electronically by feeding Vout into a high-gain amplifier, or we can amplify the mechanical pressure itself before applying it to the piezoresistor. The latter approach can be realized by constructing the piezoresistor into a cantilever structure. Deflection of the cantilever tip induces stress at the base of the cantilever near the attachment point. If properly designed, the cantilever can amplify the applied stress by several orders of magnitude. Exercises: 2-11 (15pts) : 2-12 (15pts) : Problems: 2.60 (20pts) : 2.62 (20pts) :
Homework%206_1105_solutions.docx