Phy12l E306 ISI-Paper

Profound analysis of voltage, current and resistance in series and in parallel circuits using the principles of Ohms LawM.G. Reyes1, J.G. Ilejay1, P. Valdez3, A. Verdillo2, M.G. Macarubbo4, G. Cua11 School of Electrical, Electronics and Computer Engineering2 School of Civil, Environmental and Geological Engineering3 School of Chemical Engineering and Chemistry4 School of Manufacturing Engineering

AbstractStudying the basics of electronics are very important to almost all field in the industry especially now that we are at a modern age. This experiment revolves around the simple concept of electronics, involving voltage, current and resistance. The relationship between the three is governed by the formula V=IR, from the Ohms law. The objective is to determine the total current flowing through a series and parallel circuit, the voltage across each resistors, and the current flowing through a series and parallel circuit. It also aims to investigate the relationship between voltages across each resistor and the total voltage and the relationship between current flowing through each resistor and total current. To obtain the objectives, we used resistance boxes, 1.2 batteries, connecting wires, VOM, and ammeter; we create a set up that portrays the two parts of the experiment. In the first part, the circuit created was connected in series and in the second part it is connected in parallel. After the experiment was done, the values of voltages for the parallel circuit across each resistance were recorded as 6.17V; the current flowing were 0.02A for the first and second resistance, 0.04A for the third resistance. Thus, proving that if the circuit is in series the current would be constant, otherwise, if it is in parallel the voltage would be constant. Sources of error like inaccurate readings from VOM, mistakenly placed wires and a not so constant temperature were considered in analyzing the data gathered.

I. IntroductionThe use of electronics is ubiquitous, we use various devices that applies electronics to accomplish specific tasks in our lives. There are many components of an electronic circuit, but the three fundamental components are the resistor, voltage, and current. The two simplest ways to connect these components are through series and parallel. Components connected in series are connected along a single path, so the same current flows through all of the components. Components connected in parallel are connected with multiple pathways so the same voltage is applied to each component. [1] The relationship that exists between current, resistance, and voltage is governed by the Ohms Law. Ohms Law states that the potential difference across a particular sample of material is proportional to the current provided that the temperature and other properties of the material remain constant. [2] When resistors are connected in series, only one current flows making the current constant for all the resistor in the circuit. When resistors are in parallel, the voltage across each individual resistor is equal to the voltage across the battery. [3]In this this experiment, we determine the total current flowing through a series and parallel circuit, the voltage across each resistors, and the current flowing through a series and parallel circuit. We also investigate the relationship between voltages across each resistor and the total voltage and the relationship between current flowing through each resistor and total current.II. MethodologyThe materials needed in order to obtain the objectives of these experiment were resistance boxes, 1.2 batteries, connecting wires, VOM, and ammeter. For the first part of the experiment the resistors were connected in series. We then connected the five batteries as shown in figure 306-1. Using three resistors, the circuit was built by connecting the wires. The VOM was connected across the resistors one at a time to measure the voltages: It must be noted that in measuring voltage turn the selector knob so that it points to the desired range of voltage. The VOM was connected to the circuit at points: A, B, C, D. It must also be noted that in measuring the current turn the selector knob so that it points to the desired range of current. The equivalent resistance must be determined. Lastly, the value of the total current flowing through the circuit and the current flowing through each resistor and voltages across each resistor using equivalent resistance and the measured voltage ( across the batteries will be computed using Ohms Law and rules for series circuit. Same procedures would be followed for the part two of the experiment, in which the resistors were connected in parallel. The batteries were connected differently and it is illustrated in figure 306-2. Figure 306-2 Actual image of Parallel Circuit Set-upFigure 306-1 Actual image of Series Circuit Set-up

III. Results and DiscussionResistance 1 (R1), 100

Resistance 2 (R2), 100


Total Resistance (RT), 300

Total Voltage (VEA), V6.28

TABLE 306-1: SERIES CIRCUIT

ExperimentalComputed

Voltage Across Resistance 1, V2.062.0933



Current Flowing through Resistance 1, A0.020.0209



Total Current, A0.020.0209

Percentage Difference4.56%

The table above shows the values of the resistance that weve used in the experiment. Table 306-1 shows the summary of data that weve collected in our experiment. The second column is for the experimental value while the third column is for the computed value. The two values will be used in checking the validity of the experiment. If the values produce in the second column were close to the values in the third column, which means there is small percent difference, we could say that our experiment agrees with the theory. The results of the experiment agrees with the theory. As we can see on the table 306-1, the current is the same for the entire circuit which follows that when resistors are connected in series, only one current flows making the current constant for all the resistor in the circuit. When resistors are connected in series their combined resistance is equal to the individual resistances added together.[4] But we could also observe that the voltage in table 306-1 doesnt change, the reason for that is just because the values that we set for all the resistance are the same. We set the value 100 ohms for each resistance producing 2.06 V, but if we try to change the value of the resistance we could see that the voltage will change but the current will remain the same. We compared the results in our experiment to the actual values, the actual value come from the computation using the formula V=IR. The percent error is 4.56% which is acceptable. The causes of this error will be discussed on the latter part of the paper.Resistance 1 (R1), 500



Total Resistance (RT), 78.95

Total Voltage (VEA), V6.17

TABLE 306-2: PARALLEL CIRCUIT

ExperimentalComputed







Total Current, A0.080.0782

Percentage Difference0.37%

In table 306-2, we could observe that the voltage is constant for the whole circuit, it is governed by the principle that when resistors are in parallel, the voltage across each individual resistor is equal to the voltage across the battery. The value that we got for the voltages of each resistance appeared to be the same, 6.17V while the current flowing through each resistance were 0.02A for the first and second resistor and 0.04 for the third resistor. Comparing again the results that the Volt-Ohm meter displayed and the actual values that we computed, we could say that principle is valid since the percent error that we got is just 0.37%.The results of this experiment was also compared to various previous experiments that governs the principle of Ohms Law. The experiment of Heaston produces data that was complementary with our results. They also connected the circuits in parallel and in series, but the difference was they used other materials like light bulb and digital multimeters. [6] The voltage across their resistors was also constant when they connected the circuit in parallel and when they connected their circuit in series, the current became the constant.

The results of the experiment also tell us that resistance, current and voltage has a relationship depending on what type of circuit is it either parallel or series circuit. But we could also see that the resistance is directly proportional to the voltage but inversely proportional to the resistance. A comparison of the current produced depending on the type of connection was shown in figure 306-3. The blue line is the graph for the current in series circuit, the graph was just a straight line because just like what is said earlier, it is constant; the orange line if for the parallel circuit, the graph shows that the current is increasing every resistance.For some materials, the resistance is constant no matter how much voltage is applied across it. These materials are said to obey Ohm's Law. Since the resistance (R) is constant, a plot of voltage (V) vs. current (i) yields a straight line for these materials.[5]The sources of errors in this experiment includes the inaccurate readings from the VOM. The resistance also was only set by us, so there is a possibility that there would be some discrepancies affected by the value that is set. At the recommended resistance values, there will still be a small amount of measurement error due to the impact of the meter, but not enough to cause serious disagreement with calculated values. [7] The wires could also be mistakenly placed because we just followed the figure that is in our laboratory manual, and the figure is quite unclear. From the principle of Ohms law it was stated that temperature and other properties of the material must remain constant, so the inconsistent temperature might also affected the results of our experiment. Figure 306-3 Graph of the Current of the Series Circuit and Parallel Circuit

IV. ConclusionsIn a series circuit, each device is connected in a manner such that there is only one pathway by which charge can traverse the external circuit while a parallel circuit, each device is placed in its own separate branch.After the experiment was done all the objectives were met. We are able to determine the total current flowing through a series and parallel circuit, the total current that we got for the part one of the experiment is 0.02A and for the part two we got 0.02A. We deduce that in a series circuit the total current is also equivalent to the individual current applied in each resistance, while in a series circuit the total current is equivalent to the sum of all the current per resistance. The voltage across the battery and the voltage across each resistor is the same if the circuit is in parallel but if the circuit is in series, the sum of the voltage for each resistor is the voltage across the battery. This experiment is also valid because when we compared the data that weve gathered here to the actual value, the percent errors were less than five percent. That implies that our experiment agrees with the original theory, which is the Ohms Law. Thus, after all those information were inferred, we can conclude that the behavior of the parameters, current and voltage, in series and parallel circuits are exactly opposite with one another.For recommendations in conducting the experiment, it is important to check if the connections of wires are correct. To check that, we could apply the concepts in the theory. The sources of errors would be lessen if that would be done. AcknowledgementsI would like to express my sincere appreciation and gratitude to my instructor in physics laboratory, Prof. Michael Andrei Paguio, for his exceptional help during the performance of this experiment. I would also like to thank my professor in physics lecture, Engr. Resmond Reao for teaching me the concept about parallel and series circuit. To the lab assistants, Mang Gerry and Mang Jose, thank you for providing us knowledge on how to use the laboratory apparatuses and for letting us lend those. Last but not the least; I would like to thank God, my Creator, for guiding and providing me with enough knowledge and wisdom in order to understand the concepts of circuits, to conduct the experiment, and to make this scientific paper. To God be the glory.

References[1] Soclof, S., (January 21 2008). How Circuits Work. Retrieved from http://science.howstuffworks.com/environmental/energy/circuit5.htm[2] Young, H. & Freedman, R., (2011). University Physics. Australia, NWS: Pearson. [3] Parks, J., (August 2007). Ohms Law III -- Resistors in Series and Parallel. Retrieved from http://www.phys.utk.edu/labs/ohms%20law%20series%20parallel%20resistors.pdf[4] cdac.olabs.co.in,. (2011). Verification of Ohm's Law. Retrieved 2 July 2015, from cdac.olabs.co.in/?sub=74&brch=9&sim=75&cnt=2[5] (2013). Ohm's Law. Retrieved from http://www.physics.smu.edu/~scalise/emmanual/ohm/lab.html[6] Heaston, W., Ohms Law Experiment. Physics221. [7] EETech Media. (2010). Basic Concepts and Test Equipment. Retrieved from http://www.allaboutcircuits.com/textbook/experiments/chpt-2/ohms-law/

Phy12l E306 ISI-Paper

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