Mechatronic Systems Engineering 2201A/B Lecture Notes - Lecture 15: Strain Gauge, Charles Wheatstone, Electrical Network
12 Jan 2020
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Wheatstone bridge: electrical circuit which is used to measure small changes in electrical resistance. Wheatstone bridge consists of a voltage source vex and two parallel voltage divider circuits which consist of resistances r1, r2 and r3, r4, respectively. In this case the bridge is called balanced. If resistance in any arm of the bridge is changed, the output voltage vo becomes nonzero. The output voltage vo can be derived using kirchhoff"s law: Suppose r0 is the nominal resistance of the strain gauge, r0 = r1 = r2 = r3, and rg = r0 + r. As is very small as compared to r0 (which is the case for strain gauges), can be. Recall that , where is the strain and is the gauge factor dropped from the denominator to obtain:
