Students will become familiar with dc potentiometers circuits and ohms law. What errors may happen during the experiment of ohms law. Wires have resistance that depend on wire size, length, and type of material. This chapter is largely a tutorial on handling experimental errors of measurement. Lab 3 dc circuits and ohms law introduction during the nineteenth century so many advances were made in understanding the electrical nature of matter that it has been called the age of electricity. The website is a dedicated resource for ohms law, calculation tools, applications and theoretical calculations on ohms law. Aim of experiment the main purpose of this laboratory experiment is. As you may have noticed, ohms law is an equation in the form of a straight line. Calculations verification of ohms law report the theoretical calculations are achieved from the original formula, v ir. Then, solve the system to obtain a theoretical value for each current.
The current measurement in the fluke manual has an error of 1 %. Since, temperature is a factor affecting resistance, a drawback of the procedure is. The measurements were made by highschool students in a laboratory session under guidance. As you may have noticed, ohm s law is an equation in the form of a straight line. The current that flows through most substances is directly proportional to the voltage v applied to it. An ohms law experiment for this experiment, we want to use a 9 volt battery to power an led.
Nov 14, 2014 the experiment on the hookes law will help to determine the behaviour of three different elastic materials, and help to investigate the differences of their behaviour around their elastic regions. Ohms law states that the total current in a circuit i is equal to the total impressed voltage e divided by the total series resistance r. While ohms law for a part of a circuit offers no help in experiment, it also has. In this lab, you will use a variable power supply to subject a resistor of known resistance to a variety of voltages. The current flowing through the resistor is directly proportional to the voltage applied across it. Always use pretested precision resistors with extremely low tolerance, gold band or stated tolerance andor precision potentiometers for variable resistances, unless it is used for determining the unknown variable resistance. Experiment investigate the validity of ohm s law aim. This is a very simple experiment enabling to focus on the philosophy of experimentation, error analysis. Ohm discovered a linear relationship between voltage and current in many circuit elements. Exploring ohms law in parallel and series circuits weconsider thatall resistance loads were similar in thecircuits, can obtain total current in the parallel circuit is 9 times higher than the electric current in the series. Power supply for this experiment current controls need to be turned completely counterclockwise we will later adjust the current to 1a. Construct a circuit using resistors, wires and a breadboard from a circuit diagram. In addition, a dc voltmeter and a dc ammeter must be used properly in order to correctly measure the current and voltage present in the two circuits that are to be built.
Since, temperature is a factor affecting resistance, a. Leds are fragile and can only have a certain amount of current flowing through them before they burn out. Hookes law experiment hookes law experiment and analysis. The student must be able to do a regression analysis that is appropriate to the experiment. In addition, a dc voltmeter and a dc ammeter must be used properly in order to correctly measure the current and voltage present in the two circuits that are.
By knowing this simple law, you understand the concept that is the basis for the analysis of any electrical circuit. Seminar assignments ohms law abstract and discussion. V i r where v is voltage volts,i is current amps, andr is the resistance of the circuit element that we now measure in the unit of ohms. A weakness in my experiment is my graph of the results. Experimental errors and error analysis wolfram language.
Two resistors will be used with resistances varying by nearly three orders of magnitude. To study ohm s law for dc circuits, to learn basic construction and measurement of electric. The aim of experiment is to investigate the relationship between voltage and current for both a light bulb filament and an exposed filament. The german physicist georg simon ohm 17871854 was the first to demonstrate experimentally that the current in a metal wire is directly proportional to the voltage applied. P power is the amount of current times the voltage. Click the box next to the current data for r2 and click. As always, you can find a summary online at hyperphysics1. This lab activity will challenge you to verify ohms law in a variety of. Comparison of the results with experiment and with a simplified analysis using torricellis law is made. Kirchoffs laws deal with the voltage and current in the circuit. In the next experiment well try a familiar experiment to measure g and do the calculations using the rules weve just discussed. Use the scopes builtin analysis tools to determine the voltage and current for the tenohm resistor. One such advance was made by a german physicist named georg simon ohm. Much of the material has been extensively tested with science undergraduates at a variety of levels at the university of toronto.
Ohm s law states that the resistance r is related to the voltage v and the current i across the resistor according to the following equation. This lab activity will challenge you to verify ohm s law in a variety of. I had a quick look but i dont understand experiment 3. Resistance, ohms law, and i v curves lab report studocu. Imagine that we are trying to determine an unknown resistance using this law and are using the philips meter to measure the voltage. Record your results in your data table, and be sure to show a sample calculation. The letter p represents power in ohms law formula while watts is the unit of measurement. Verification of ohms law qassim university college of engineering phys. For this experiment, we will be studying a material known to obey ohm s law. To verify ohms law, which defines the relationship between voltage, current and resistance in a series circuit. Ohms law states that the resistance r is related to the voltage v and the current i across the resistor according to the following equation. Recapitulating basic measurement and error analysis skills. Experiment investigate the validity of ohms law aim.
Wires add series resistance to circuits, just as good and bad connections add also. Students will also be introduced to the resistor color code and refresh their graphing skills. Sep 15, 2012 for the first experiment, lets consider the measurement at the bottom of the table. Experiment 2 ohms law print 1 copy of the report page to start your lab report print 2 copies of the data page file object. Ohms law lab report with graph, observations and verification. Ohms law is an empirical formula which relates the voltage drop across a resistor to the current through. If youre looking to study further into more complex applications of ohms law and the design of electrical circuits, be sure to check out the following hands on activities. Physics 263 sample lab report the attached lab report is an. The overall experiment went well, and it succeeded the purpose of the trial which was how changing the voltage could affect the amount of current flowing in a series circuit while being able to prove ohms law. For the final part of the experiment, close out of the ohms law file, and open the second ohms law file. The experiment on the hookes law will help to determine the behaviour of three different elastic materials, and help to investigate the differences of their behaviour around their elastic regions. For the first circuit, use equations 1 and 2 to write a system of linear equations that may be solved for the current in each branch of the circuit. Ohms law is the fundamental law of electrical engineering.
This article presents the complete ohms law lab report. Here r is the reciprocal slope of your graph, and has units of ohms volts amperes. Imagine that we are trying to determine an unknown resistance using this law and are. If youre looking to study further into more complex applications of ohm s law and the design of electrical circuits, be sure to check out the following hands on activities. Be sure to leave the legend displayed on your graph. The purpose of this measurement is to verify ohms law vir for. To study ohms law for dc circuits, to learn basic construction and measurement of electric. Ohm performed repeated experiments on a resistor, applied different voltages, measured current and found relationship between these quantities. Experiment 3 ohms law, measurement of voltage, current.
Experiment 2 ohm s law print 1 copy of the report page to start your lab report print 2 copies of the data page file object. Your objective will be to test ohms law, which asserts that the resulting current through the resistor as well as the rest of the circuit is proportional to the applied voltage. For this experiment current controls need to be turned completely counterclockwise we will later adjust the current to 1a. Ohms law for electrical resistance, v ir, states the relationship between current, voltage, and electrical resistance. Seminar assignments ohms law abstract and discussion studocu. Theoryohms law states that in a resistive circuit, when the resistance is kept constant, the current through theresistor is directly proportional to the voltage across the resistor.
Experimental verification of kirchhoffs voltage law and kirchhoffs current law abstract we have experimentally tested kirchhoffs voltage law and kirchhoffs current law by measuring the sum of the voltage drops around several closed paths, and the sum of the currents at several nodes, in two resistive circuits. Electronic devices and to see whether they satisfy ohm s law. Measurement and error analysis homework reading prior to lab. You can also verify them from the basic ohms law calculator. The circuit appears to show two resistors in series but where they calculate r value from mathematical formula it assumes they are in parallel. Lets start off by understanding the types of errors. Theoryohms law states that in a resistive circuit, when the resistance is kept constant, the current through theresistor is directly.
Ohms law iiiresistors in series and parallel however, all wires that make connections and the connections themselves qualify as series resistance. Electronic devices and to see whether they satisfy ohms law. Print 1 copy of the report page to start your lab report. The measurements were made by highschool students in a. Experiment 3 ohms law, measurement of voltage, current and.
Use the scopes builtin analysis tools to determine the voltage and current for the ten. The summary report includes a short discussion of the results after processing the data gathered. Set up currant and voltage ranges in the graph by using ohms law. There are many ways to write up a lab report, none of them superior to. Using the currents obtained in step 1 of the analysis.
Verification of ohms law, kirchoffs voltage law and. The objective of this lab is to apply ohms law to both series and parallel dc circuits. Go to graph mode by dragging and dropping the graph from the left panel. Ohms law by the end of this experiment, the student must come up with a summary report for the experiment. An ohm s law experiment for this experiment, we want to use a 9 volt battery to power an led. Nov 14, 2010 the aim of experiment is to investigate the relationship between voltage and current for both a light bulb filament and an exposed filament. One of the fundamental rules for electrical engineers is ohms law, named for georg simon ohm 17891854. Experimental verification of kirchhoffs voltage law and. Calculate the current from a constant 5 volt input by using equation 1. The watt w is a measurement of power in an electrical circuit. He finally published the law in 1827 and generalized his observations in single statement.
Choose voltage in vertical axis and current in horizontal axis. When the green power button is pushed in, the power supply is on. If a voltmeter is used to measure the voltage v across an unknown resistance r, and an ammeter is used to measure the current i through the same unknown resistance, then r would be given by r vi. Ohms law is named after george simon ohm a german physicist. Make sure the labpro interface is plugged into the usb port of the computer, its power supply is plugged in, and the interface is turned on. Enter the data from table 2 into excel, and plot it with current on the xaxis and voltage on the yaxis. Objectiveto experimentally verify ohms law through measurement and to confirm findings by comparingmeasured values with prediction. The units youll use today are kilohms milliamperes k. Students will be expected to give details of equipment used, assembly of equipment, data collection, data manipulation including graphs where relevant. Appendix b, appendix c dmm objective the objective of this lab is to determine the resistance of several resistors by applying ohms law. Pdf difficulties in learning ohms law suggest a need to refocus it from the law for a part of the circuit to the law for the whole. Ohms law and kirchoffs laws were found to be valid after comparing the results from all three tests. The procedure involves using a light bulb, which when an electric current passes through it begins to heat up. It relates the current flowing through any resistor to the voltage applied to its ends.
To collect the data, experiment needs to be performed using three different types of materials,material 1, material 2 and material 3. Analysis for most single solid materials at constant temperature, the relation between current and voltage is linear, making it useful to define resistance and ohms law. Voltage controls completely clockwise notice that there is a. Voltage controls completely clockwise notice that there is a coarse and fine adjustment for both current and voltage. Whole books can and have been written on this topic but here we distill the topic down to the essentials. Students will also be expected to know the conclusion or result of an experiment and appropriate precautions. The real practically calculated red color vs the theoretical values blue are plotted on the graph. Youll also learn to obtain quite accurate readings. For each trial, calculate the percent of difference between the calculated and measured current in the circuit. The objective of this lab is to apply ohm s law to both series and parallel dc circuits. If the connections are soldered, then coldsolder joints can be a contributing factor to errors or poor connections in general. The attached lab report is an example of what is considered an appropriate lab report in this course.
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