Page 1Page 2Page 3Page 4Page 5Page 6Page 7Page 8Ohm’s LawObjective:Firstly, to determine the mathematical relationship between current, potential difference, andresistance. After this, a comparison will be made of the potential vs current behavior of a resistorand a light bulb..Apparatus: 1 Lab Pro Device1 Ti Graphing Calculator with DATAMATE program installed1 Adjustable DC power supply1 Vernier Circuit Board1 Current and Charge Voltage system1 Voltimeter1 WireMethod:The fundamental relationship among the three important electrical quantities current, voltage,and resistance was discovered by Georg Simon Ohm. The relationship and the unit of electricalresistance were both named for him to commemorate this contribution to physics. One statementof Ohm’s law is that the current through a resistor is proportional to the potential differenceacross the resistor. Ohm’s Law is commonly stated mathematically as V=I*R. In thisexperiment you will test the correctness of this law in several different circuits using a CurrentProbe and a Voltage Probe. These electrical quantities can be difficult to understand, because they cannot be observeddirectly. To clarify these terms, some people make the comparison between electrical circuits andwater flowing in pipes. Here is a chart of the three electrical units we will study in this experiment.Figure 1: Image taken from the12volt.com websiteElectrical Quantity Description Unit Water AnalogyVoltage or PotentialDifferenceA measure of the Energydifference per unit chargebetween two points in acircuit.Volt (V) Water PressureCurrentA measure of the flow ofcharge in a circuit.Ampere (A) Amount of waterflowingResistanceA measure of howdifficult it is for current toflow in a circuit.Ohm (W) A measure of howdifficult it is for waterto flow through a pipe.Resistors are labeled with a rated resistance and a percentage tolerance, which specifies howmuch the value of resistance may vary from the rated value. The rated resistance value is usuallyindicated with a color code. Most ordinary carbon-composition resistors are labeled with four colorbands, as shown below in Figure 1.The color codes used for carbon resistors are listed in Table 1 on the next page. The first twobands are read as a two-digit number. The third is read as a power-of-ten multiplier of thatnumber. The fourth is the tolerance rating. Tolerance is a percent rating, showing how much theactual resistance could vary from the labeled value The resistance value of a resistor can becalculated according to Eqn. 1 below:Resistance value = (2-digit # from first 2 bands) * 10Eqn. (1)(3rd band digit)Figure 2 Table 1:Color Numberfor band 1-3Band #4 ToleranceRatingBlack 0 ---Brown 1 ± 1%Red 2 ± 2%Orange 3 ---Yellow 4---Green 5± 0.5%Blue 6± 0.25%Violet7± 0.1%Gray 8± 0.05%White 9---Gold 0.1±5%Silver 0.01±10%Setup:1. Connect the Current & Voltage Probe System to the LabPro interface:a. Connect DIN 1 on the Dual Channel Amplifier to Channel 1 of the LabPro or CBL 2 interface. b. Connect DIN 2 to Channel 2. Then connect a Current Probe to PROBE 1 on the Dual Channel Amplifierand a Voltage Probe to PROBE 2. 2. Use the black link cable to connect the LabPro interface to the TI Graphing Calculator. Firmly press in the cableends. 3. Turn on the calculator and start the DATAMATE program.Note: If the DATAMATE program is not stored in the calculator, follow the directions in Appendix D-DataMateGuidebook to transfer the program from the LabPro to your calculator.4. If CH 1 displays the Current Sensor and CH 2 displays the Voltage Sensor, proceed directly to Step 5. If it doesnot, set up your sensors manually. To do this:a. Select SETUP from the main screen.b. Press ENTER to select CH 1.c. Select C V SYSTEM from SELECT SENSOR. d. Select CV CURRENT (A) from C V SYSTEM.e. Press DOWN to select CH2 and press ENTER .f. Select C V SYSTEM from SELECT SENSOR. g. Select CV VOLTAGE (V) from CV SYSTEM.h. Select OK once to return to the main screen.5. Connect the circuit shown in Figure 2:a. With the power supply turned off, connect the power supply to the input terminal posts on the Vernier CircuitBoard. Note that switch 1 (SW1 SPDT), which is connected to the input terminal posts, is off when in the“up” position. Keep the switch in the off position when you are not taking measurements. b. Use wires to connect the DC voltmeter directly to the output terminal posts of the Power Supply. Take careto connect the positive post to the appropriate input terminal post of the DC voltmeter, depending on thevoltage level needed. You will use the reading on the DC voltmeter when adjusting the Power Supplyvoltage. c. Connect a 10-S resistor, wires, the current sensor, and the voltage sensor as shown in Figure 1. Take carethat the positive lead from the power supply and the red terminal from the Current & Voltage Probe areconnected as shown in Figure 2. Note: Attach the red connectors electrically closer to the positive side of the power supply. Have your instructor check the arrangement of the wires before proceeding.6. Now, you will need to zero both probes with no current flowing and with no voltageapplied (power supply off).a. Select SETUP from the main screen.b. Select ZERO from the setup screen.c. Select ALL CHANNELS from SELECT CHANNEL.d. Press ENTER to zero the sensors.7. *NOTE: The maximum voltage which can be applied to the input terminals of the circuitboard is 10 VDC. The resettable fuse on the circuit board will be tripped at 0.8A . Thecurrent and voltage readings are shown on the main screen, updated about once a second.Turn the control on the DC power supply to 0 V and then turn on the power supply.Slowly increase the potential to 5 V. Monitor the readings on your calculator and describewhat happens to the current through the resistor as the potential difference across theresistor changes. If the potential doubles, what happens to the current? What type ofrelationship do you believe exists between potential difference and current?Procedure:1. Set the data collection mode so that the interface will record the potential and current only attimes you specify:a. Select SETUP from the main screen.b. Press UP to select MODE and press ENTER. c. Select SELECTED EVENTS from the SELECT MODE menu. d. Select OK to return to the main screen.2. Record the value of the resistor in the Data Table.3. To collect your first point of current and potential data,a. Select START from the main