# Ohm's Law Lab Case

Essay by   •  February 21, 2015  •  Essay  •  417 Words (2 Pages)  •  1,743 Views

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The purpose of this lab was to examine Ohm's Law to determine the resistance of a resistor and to distinguish whether or not a device was ohmic. Series and parallel configurations of resistors were analyzed and simplified. Ohm's Law states that the current through a resistor is directly proportion to the voltage and inversely proportion to the resistance. In the first part of the experiment using a measured resistance of 220 ohms, voltage was gradually increased and current for each voltage increment was recorded. Voltages 5.235 through 14.737V resulted in currents of 23.8 - 68.9mA. In part 2, the manufacture's listed resistance used was 1.8 kOhms. The measured resistance using an ohmmeter was also 1.8 kOhms. The Voltage ranged from 1.97V - 14.95V. The current was 1.09 mA - 8.35mA. This was a linear relationship which was ohmic. The resistor in the circuit was replaced with a lightbulb. The voltage ranged from 0.64V - 7.933V and the current ranged from 0.738A - 2.7A. This was not ohmic and did not display an inverse or linear relationship. In part 3, two different resistors were chosen with R1 listing 1.5 kOhms and R2 2.7 kOhms. The measured resistance was the same for each. R1 and R2 in a series measured resistance was 4.72 kOhms and the calculated resistance was 4.21 kOhms. The percent error was 12%. In part 4, the same resistors were used from part 3 and placed in parallel configuration. The measured resistance in R1 and R2 in parallels was 1.134 kOhms and the calculated resistance was 4.21 kOhms. The percent error was 73%. In part 5, R1, R2, and R3 had a listed resistance of 1.5, 2.7, and 2.2 kOhms, respectively. The measured resistances were the same for each. The experiment showed that when voltage increased, current increased and when voltage decreases, current flow decreases. The results also showed that when the resistance increased in the circuit the current flow decreased. This agrees with Ohm's law, which states, "The amount of current flowing in a circuit made of pure resistances is directly proportional to the electromotive forces impressed on the circuit and inversely proportional to the total resistance of a circuit." Possible sources of error could come from the wire connectors not connecting properly due to not being tight enough. The springs on the grips could have lost some tension therefore not gripping the resistors properly possible losing volts. A way to improve the experiment would be using equipment

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