Microsoft_PowerPoint___EC4intro - EC4 Wheatstone Bridge In this lab you will accomplish the following tasks 1 Become familiar with the use of the

# Microsoft_PowerPoint___EC4intro - EC4 Wheatstone Bridge In...

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EC4 Wheatstone Bridge In this lab you will accomplish the following tasks: 1. Become familiar with the use of the Wheatstone bridge 2. Use the DC Wheatstone bridge to measure a resistance 3. Use the AC Wheatstone bridge to measure a resistance 4. Use the AC Wheatstone bridge to measure a capacitance (page 1)
E R 3 G I R 1 R 2 R X A B D C The arrangement of four resistors shown in the figure is known as the “Wheatstone bridge” We monitor the current I through branch DC of the bridge using the galvanometer G. ( A very sensitive ammeter is known as a “galvanometer” ) By varying R 1 , R 2 , and R 3 we can make the potential at point C be equal to the potential at point D i.e. V C = V D . When this condition is satisfied then the current I = 0 and thus the reading the of galvanometer is zero. We say that “the bridge is balanced”. When I = 0 the four resistors satisfy the equation: R X R 1 = R 2 R 3 If we solve this equation for R X we get: 2 3 1 X R R R R = (page 2)
Sections V-1, V-2