Problem 10E The electrical network shown in the accompanying figure is called a Wheatstone bridge. In this bridge, R2 and R4 are known resistances and R3 is a known resistance that can be varied. The resistance R1 is unknown and is to be determined by using the bridge. The resistance R5 represents the internal resistance of a voltmeter attached between nodes B and D. The bridge is said to be balanced when R3 is adjusted so that there is no current flowing in the branch between B and D. Show that, when the bridge is balanced, R1R4 = R2 R1. (In particular, the unknown resistance R1 can be found from R1 = R2R3/R4 when the bridge is balanced.)
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Textbook Solutions for Introduction to Linear Algebra
Question
The electrical network shown in the accompanying figure is called a Wheatstone bridge. In this bridge, R2 and R4 are known resistances and R3 is a known resistance that can be varied. The resistance R1 is unknown and is to be determined by using the bridge. The resistance R5 represents the internal resistance of a voltmeter attached between nodes B and D. The bridge is said to be balanced when R3 is adjusted so that there is no current flowing in the branch between B and D. Show that, when the bridge is balanced, R1R4 = R2 R1. (In particular, the unknown resistance R1 can be found from R1 = R2R3/R4 when the bridge is balanced.)
Solution
The first step in solving 1.4 problem number 10 trying to solve the problem we have to refer to the textbook question: The electrical network shown in the accompanying figure is called a Wheatstone bridge. In this bridge, R2 and R4 are known resistances and R3 is a known resistance that can be varied. The resistance R1 is unknown and is to be determined by using the bridge. The resistance R5 represents the internal resistance of a voltmeter attached between nodes B and D. The bridge is said to be balanced when R3 is adjusted so that there is no current flowing in the branch between B and D. Show that, when the bridge is balanced, R1R4 = R2 R1. (In particular, the unknown resistance R1 can be found from R1 = R2R3/R4 when the bridge is balanced.)
From the textbook chapter Applications (Optional) you will find a few key concepts needed to solve this.
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