Experiment EC4: Wheatstone BridgeIn this experiment you will accomplish the following tasks:1) Use a Wheatstone bridge with a DC power source to determine the resistance of an unknown resistor.2) Use a Wheatstone bridge with an AC power source to determine the resistance of an unknown resistor.3) Use a Wheatstone capacitance bridge with an AC power source to determine the capacitance of an unknown capacitor.Consider this circuit. The upper branch is in parallel with the lower branch. This means that the potential difference across the upper branch is equal to that of the lower branch.13 11232122 xxVV IRIRVV IRIRIf we vary R1, R2and R3such that the potential difference betweenpoints A and B = 0, the bridge is balanced and the following equations hold:13 11232122 xxVV IRIRVV IRIRSolving this system of equations for Rxgives231xRRRRSince the resistance of a uniform wire is proportional to its length, we can use a long wire for R1 and R2. We vary the value of R1and R2by changing the location of contact B.231xlRRllRBecausewe can replace R2/R1with l2/l1 givingImportant!Before connecting either power supply (DC or Function Generator)use the DMM to adjust the output voltage to be between 2.0 and 2.5Volts. This is to protect the power supplies from overcurrent.When measuring DC volts, the DMM should be set to read DC volts(solid straight line over dashed straight line next to letter V.)When measuring AC volts, it should be set to AC Volts (~ next to the letter V).Point B should be approximately 50 cm. Adjust R3to get a minimumvoltage reading on the DMM. Finally, adjust the position of point Bto get the DMM reading as close to 0 on the 200 mV scale as possible.The bridge is now balanced.V-1Assemble the circuit shown using RAas the unknown resistor. The DC power supply should be set to approximately 2.5 volts. The DMM should be set to DC voltsFor all four unknown resistors, do the following:After the bridge has been balanced, record l1, l2, R3.Estimate and record the uncertainty in length, l.Finally, disconnect the unknown resistor from the circuit and then measure and record the resistance Rmusing the DMM.VI-1 of the reportTabulate the data from V-1 including the following:For each unknown resistor, tabulate l1, l2, R3and RmDetermine and report Rx±Rxfor all four resistorsCompare the resistance determined from the Wheatstone bridge to the resistance using the DMM.Use the same technique as in V-1 to balance the bridge. The DMM should be set to read AC volts instead of DC volts.V-2Turn off the DC power supply and disconnect it from the circuit.Replace the DC power supply with the function generator. The frequency should be approximately 1 kHz, the amplitude should be set to approximately 2.5 V. The output should be set to a sine wave (the LED above the sine wave button will be lit)For all four unknown resistors, do the following:After the bridge has been balanced, record l1, l2, R3.Estimate and record the uncertainty in length, l.Finally, disconnect the unknown resistor from the circuit and then measure and record the resistance Rmusing the DMM.VI-2 of the reportTabulate the data from V-1 including the following:For each unknown resistor, tabulate l1, l2, R3and RmDetermine and report Rx±Rxfor all four resistorsCompare the resistance determined from the Wheatstone bridge to the resistance using the DMM. Compare the values determined by using an AC power source to those determined by using a DC power source.V-3You will now use an arrangement of capacitors as a Wheatstonebridge to determine an unknown capacitance.This circuit functions in much the same way that the wire bridge circuit did. C1and C2take the place of l1and l2. C3is adjusted to balance the bridgeFor both of the unknown capacitors CAand CB:Assemble the circuit shown on the previous slide. The DMM should be connected to points A and B, set to read AC volts. C1and C2are identical capacitors at the bottom of the circuit unknowns box. Adjust C3until the DVM reading is at a minimum. This is asclose to balanced as you can get with this equipment.Finally, disconnect the capacitors and use the DMM to directly measure the capacitance Cmof both capacitors.VI-3 of the reportTabulate the data from V-3 including the following:For each unknown capacitor, tabulate C3and CmDetermine and report Cx±Cxfor both capacitors.Compare the capacitance determined from the Wheatstone bridge to the capacitance using the