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Phys 102 Kikchoff’s Current and Loop Laws Manju Sogi & Alma Fuentes Abstract This experiment will introduce Kirchhoff’s circuit laws and will be applied to elementary multi-loop circuits, while comparing measured branch current with predicted currents. Equipment Breadboard Resistor 10< R < 100 Ohms Old fashioned ammeter Batteries Procedure 1. Choose three resistors and named them R1, R2, R3, record their values. 2. Build the following circuit. 3. Record the voltage across each circuit and current across each branch. 4. Build the circuit number 2. 5. Measure the voltage across each circuit and current in each branch. Data Circuit 1 Circuit 2 V1 V2 V3 Volts 0.369 6.44 5.58 Volts 1.89 0 4.98 I1 I2 I3 mAmps 1.98 7.9 9.9 mAmps 5.98 0 5.98 Ohms 180 820 560 Ohms 180 120 560 820 R1 R2 R3 R4 Calculations Circuit 1 Theoretical I1= I2+I3 V1-I1R1-I2R2-V2-V3=0 V3+V2+I2R2-I3R3=0 mAmps I1=2.2 I2 = -7.8 I3 = 10 Circuit 2 I2 = 0 I1= I3 V1-R1I1-I1R4-V2-V3=0 6-180I1-I1820-3-9=0 I1= 6 mAmps I3= 6 mAmps I2 = 0 mAmps Error Analysis The purpose of this lab was to obtain results for inaccurate equipment and make conclusions based on those measurements. The use of the old fashioned ammeter is difficult to use and therefore causing errors to be taken account. The use of the breadboard and wires also contain errors that need to be taken into account. % Error = [Theoretical – Experimental] X (100) Theoretical Circuit 1 I 1 % Error = 2.2-1.98 X 100 = 10 % 2.2 I2 = 1.28% I3 = 1.01 % Circuit 2 I 1 % Error = 6-5.98 X 100 6 = .33 % I2 = 0 % I3 = .33% Conclusion In this experiment, we learned to apply Kirchhoff’s circuit laws to some elementary types of multi-loop circuits, as well as comparing our measured branch currents with the theoretical. Per data and after doing calculations we had .33% error in the second circuit for the first current and the third current which was a small error percentage. However for the second current we had a 0% error because our measured current was the same as the theoretical. The error percentage could be attributed that the positive and negative wires had a small give or take amount within the bread board circuit thus our data had a percentage error. Furthermore, error in data could’ve been due to flaws in equipment or inaccuracy due to human error while reading the voltmeter. In theory, we should’ve measured the theoretical values as stated above but weren’t able to achieve due to error possibilities in equipment or the human eye as mentioned above. Grade = 100