A Wheatstone bridge is used to achieve a very high precision measurement of electrical resistance. This precision is so great that it surpasses that of ohmmeters, voltmeters, and ammeters. A galvanometer is also used with a Wheatstone Bridge. A galvanometer is a meter that is very sensitive to extremely small units. A diagram of the Wheatstone Bridge is shown below.
In this experiment, we used an unknown resistance equation to find Rx (the unknown). The equation that was used for finding the unknown resistance in this circuit was Rx (L1/L2) Rs. Length one and length two were found by balancing the bridge. It was known that the bridge was balanced when the slide was positioned where no current would flow through the galvanometer. A resistor with a known resistance was used for Rs. There is a precision of about 0.4% because the bridge was able to be balanced with an accuracy of 1mm.
