Physics Lab Report #5 - The Wheatstone Bridge PDF

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The Wheatstone Bridge...

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Physics Lab Report The Wheatstone Bridge Method Prof. Tsiklauri Carlos Vides PHY 225 Lab #5

1. Objective - To experimentally determine unknown resistances by means of a Wheatstone bridge. -To measure resistance by means of the Slide Wire Wheatstone Bridge.

2. Procedure First we connected the Wheatstone bridge circuit by using the diagram in the book. Then we activated the circuit and balanced it by moving the slide-wire contact tool. We obtained our measurements of L2 and L1 and recorded it on our table. When the bridge was balanced, the current through our galvanometer was zero, and we looked for our measured resistance with the simple equation: Rs L 2 = R x L1

Tools Wheatstone Bridge Galvanometer Connecting Wires D.C. Power Supply 2 Resistors

3. Data and Calculations

Table 1 Rs (#) 1 2 3 Average

L1 (m) .51 .454 .38 .448

Measured Resistance ( Ω ) 492.86

L2 (m) .49 .546 .62 .552

R( Ω ) 500 400 300 400

Theoretical Resistance ( Ω ) 500

Percent Error (%) 492.86−500 ∨×100 500 1.4 %

Table 2 Rs (#) 1 2 3 Average

L1 (m) .64 .58 .51 .577

Measured Resistance ( Ω ) 293.24

L2 (m) .36 .42 .49 .423

R( Ω ) 500 400 300 400

Theoretical Resistance ( Ω ) 300

Percent Error (%) 293.24 −300 ∨× 100 300 2.25 %

4. Discussions and Conclusions This lab effectively showed how the Wheatstone bridge provides a mechanism to calculate an unknown resistance using the known relationships given through the resistivity correlation to length. It demonstrated how to set-up a Wheatstone bridge and how to manipulate a Wheatstone bridge in laboratory setting. In addition, the lab provided a demonstration of the mentioned relationship above. Although significant error existed in this lab, the results still reflect the relationships governing the Wheatstone bridge sufficiently for understanding in an experimental contextual environment...