6-Kirchhoff's Rules PHY 202

Kirchhoff’s Rules – PHY 202 Introduction The purpose of this experiment is to confirm the validity of Kirchhoff’s Rules in the analysis of DC circuits. Theory Many practical circuits consist of more than one loop of current and cannot be reduced to simple series-parallel resistor network combinations. These multi-loop circuits can be analyzed using the Kirchhoff’s Rules. Kirchhoff’s Rules state that: • • The sum of the currents flowing into any junction is zero. The sum of the potential drops around any single loop is zero. Remember that you need to generate a number of independent equations equal to the number of unknown parameters you want to determine. Also, make sure you use the correct polarity (sign) for currents and voltage drops. Practical details about how to correctly apply Kirchhoff’s Rules can be found in the class presentations and in the textbook (chapter 26). Procedure Open the PhET simulation Circuit Construction Kit DC and select Lab: https://phet.colorado.edu/sims/html/circuit-construction-kit-dc/latest/circuitconstruction-kit-dc_en.html a) Using the PhET simulation, build the circuit shown below. b) Use a simulation ammeter to determine the magnitude and direction of the currents I1, I2 and I3. (Note: if the current flows in the same direction as that pointed by the arrow assign a positive sign, otherwise assign a negative sign). c) Use Kirchhoff’s Rules to find the currents I1, I2 and I3, analytically. d) Enter your findings in the following tables (include magnitude and sign): Simulation Values (A) Analytical Values (A) I1 I2 I3 Analysis a) Do the simulation and analytical current values agree? Explain. For your lab report include: a) A screen capture showing the circuit you built using the simulation. b) Your Kirchhoff’s Rules analytical calculations. c) The table shown in the handout with the corresponding values. d) The answers to the analysis questions.