DC Circuits Lab Report, Essays (university) of Physics

Download DC Circuits Lab Report and more Essays (university) Physics in PDF only on Docsity! David Suzuki Jenna Lidua February 19, 2019 DC Circuits Lab Report OBJECTIVES The objective of this lab is to construct our very own ohmmeter that reads out a voltage and confirm Kirchhoff Rules law by measuring voltage in parallel and in series. NOTES: 𝑅𝑥 = 𝑉0 𝑘 ( 1 𝐺 ) − 𝑅𝑘 We will be using this equation to determine the resistance of the unknown resistor. This equation is written in slope form (y=mx+b) in which 𝑉0 𝑘 is the m or the slope, 1 𝐺 is the x and 𝑅𝑘 is the constant since that is the resistor, we constantly used to determine the resistance of all resistors. 𝛿𝑍 = 𝛿𝐺 𝐺2 This is the error propagation equation for when we are calculating 1 𝐺 . Since the galvanometer has an error, we must assume when calculating that there is an error equal to G, thus this simple calculation can account for the uncertainty. ∑ 𝑉𝑘 𝑘 = 𝑉1 + 𝑉2 + 𝑉3 + ⋯ + 𝑒𝑡𝑐 For the second part of the lab, we will be verifying Kirchhoff rule, by seeing whether the sum of the voltage in a circuit is conserved. Thus, the summation of all voltages must equal to 0. ∑ 𝐼𝑘 𝑘 = 𝐼1 + 𝐼2 + 𝐼3 + ⋯ + 𝑒𝑡𝑐 We will also verify the second part of Kirchhoff law by calculating that the total current in any node or connection point must be zero. PROCEUDRES: Ohmmeter (PART 1) 1. Select a resistor out of a total of six different resistors that will have the highest deflection reading 2. To verify that the resistor can be accounted as the constant, plug it into your circuit and verify that the deflection is between 3 and 4 3. Construct your Ohmmeter by following the diagram provided and ensure that the current is flowing through the circuit. Verify by seeing if adding another resistor makes the galvanometer move 4. Calibrate the ohmmeter by obtaining five different resistors and Recording what G is after inserting it into the circuit 5. Calculate for 1/G and plot data into SciDAVis with Rx in y axis and 1/G in x axis 6. The resulting slope will be used to calculate the resistance of the Unknown resistor that will be given upon calibrating the ohmmeter. Be sure to record G of unknown resistor and calculate 1/G as it is vital when finding the unknown Rx PROCEDURES: Kirchhoff’s Rules (PART 2) 1. Obtain a prebuilt circuit board 2. Using the banana cables, complete the setup by connecting all the resistors and nodes 3. First verify the voltage rule 4. Measure the voltage difference between the resistors and calculate that the result is equal to zero by using the ammeter in parallel form to prevent the ammeter from frying 5. Take data for all three voltage differences 6. Second verify the current rule by plugging the ammeter and verifying that the current traveling through the circuit sums to zero. Ensure that it is in series when completing this step DATA INPUT: (Ohmmeter) 𝑉0 = 1.5𝑉 𝑅𝑘 = 2.98Ω 𝑅𝑥 (Ω) G (meter deflection) 1 𝐺 1.496 ± 0.0005 3.1 ± 0.1 0.322 ± 0.004 7.45 ± 0.005 1.35 ± 0.1 0.74 ± 0.009 6.71 ± 0.005 1.4 ± 0.1 0.714 ± 0.001 2.394 ± 0.0005 2.6 ± 0.1 0.384 ± 0.003 5.02 ± 0.005 1.75 ± 0.1 0.571 ± 0.001 Unknown Resistor: G = 1.8 1/G = 0.556 ± 0.001