Activity 2: Resistor colour code / multi-meter readings



Sec 4 AST, ST, EST/Electricity/ Resistance Name:________________________________Factor affecting the resistance of a conductive wireA) Resistance versus the thickness (Gauge) of a conductive wire.Material:Nichrome wire #26, #22 and #182 Alligator wiresAmmeter (Reading on the power pack)Voltmeter (Reading on the power pack)Procedure:Set power pack to 3VUse 80cm long of the selected wire gauge (#26, #22 or #18)Connect the terminal of the power pack to the wireRead and record the Voltage (V) and Current (I) in ampere (Amp)Calculate the resistance in ohm using the formula: R= V/IMake a graph showing the relationship between the Resistance and the Gauge (thickness) of the Nichrome wire.*Note: The higher the Gauge number the thinner the wire.Results:_______________________(title)V(volts)I (Amp)R (Ω)Nichrome #26? = 0.4mmNichrome #22? : 0.65mmNichrome #18? : 1.02mmB) Resistance versus length of a conductive wireMaterial:Power pack with Volt and Current reading. Nichrome wire #182 alligator wires Nichrome wire gauge #18 Graph: Resistance(Ω) versus Length(m) Procedure:Set the voltage to 1.5VConnect the Nichrome wire to the power packRecord the Current reading for length 0.80m, 0.40m and 0.20mResults: Resistance/length: Nichrome wire #18V(volts)I (Amp)R (Ω)80cm40cm20cmGraph: Resistance(Ω) versus Length(m).C) Does the material a wire is made of affect its resistance?Material:2 wires (Copper and Nichrome) Gauge#26 2 Alligator wiresAmmeter (Reading on the power pack)Voltmeter (Reading on the power pack)Procedure:Set power pack to 1.5VUse 80cm long of the selected wire gaugeConnect the terminal of the power pack to the wireRead and record the Voltage (V) and Current (I) in ampereCalculate the resistance in ohm using the formula: R= V/IResults:____________________________________________(title)Length (cm)Volts (V)I (Amp)Resistance (Ω) Copper wire#26Nichrome wire #26Conclusion:How is the resistance of a wire affected by the three factors investigated?Activity 2: Resistor colour code / multi-meter readings36353751583690Info:1)Hold the resistor with the tolerance (gold or silver) at the right.2)the color line just before the tolerance is the multiplier.3)the color lines before the multiplier are the digits (left to right).00Info:1)Hold the resistor with the tolerance (gold or silver) at the right.2)the color line just before the tolerance is the multiplier.3)the color lines before the multiplier are the digits (left to right).DigitsMultiplierTolerance1-brown1-Black1%-Brown2-Red10-brown2%-Red3-Orange100-Red4-Yellow1000-Orange5%-Gold5-Green10 000-Yellow10%-Silver6-Blue100 000-Green7-Violet1 000 000-Blue8-Grey9-White0.1-gold10-Black0.01-SilverAct # 1 : Use the color code to determine the resistance of 3 resistors.2027466023400BandResistor # 1st2nd3rd4th5th6thValue(?)Act#2 -resistance value using the multimeterDetermine the value of the resistor of the 3 resistors using the multimeter.Table of results:Resistor#rangeReadingResistance (?)Conclusion/discussion How does the resistance determine with the resistor color-coding chart compare with the resistor resistance value measured by the multi-meter? Are the measured resistance within the specified tolerance value? Info:Equation representing the dependency of the resistance (R) of a cylindrically shaped conductor (e.g., a wire) upon the variables that affect it is:253873080010L represents the length of the wire (in meters), A represents the cross-sectional area of the wire (in meters2), and ρ represents the resistivity of the material (in ohm?meter)00L represents the length of the wire (in meters), A represents the cross-sectional area of the wire (in meters2), and ρ represents the resistivity of the material (in ohm?meter)R= ρ LAMaterialResistivity (ohm?meter)Silver1.59 x 10-8Copper1.7 x 10-8Iron10 x 10-8Nichrome150 x 10-8Glass1010 - 1014Hard Rubber1013Resistivity in (ohm?meter) for a few materials Measuring the resistance with a digital multi-meter.59372511811000303249081780The multi-meter you are using is a battery-operated digital type that reads out in digits on an LCD (liquid crystal display) screen. The meter is read using the appropriate scale: DC volts (DC V), AC volts (AC V), Ohms(?), or DC amperes or amps (DC A or 10 A). Other special scales available on this multi-meter are not used in these experiments. The meter is supplied with a black test lead with a probe and a red test lead with a probe. The red test lead probe is plugged into the “V? MA” jack on the meter, and the black test lead is plugged into the “COM” jack. The10 A jack is used with the red test lead to measure up to 10 A current.00The multi-meter you are using is a battery-operated digital type that reads out in digits on an LCD (liquid crystal display) screen. The meter is read using the appropriate scale: DC volts (DC V), AC volts (AC V), Ohms(?), or DC amperes or amps (DC A or 10 A). Other special scales available on this multi-meter are not used in these experiments. The meter is supplied with a black test lead with a probe and a red test lead with a probe. The red test lead probe is plugged into the “V? MA” jack on the meter, and the black test lead is plugged into the “COM” jack. The10 A jack is used with the red test lead to measure up to 10 A current.60325044450034925029570002000k 57785063754000116547511874500Black lead Red lead ( V, ?, MA)Note: Use the resistor #3 as an example. Take the resistor #3Set the dial for the Resistance reading ? Choose the largest scale: 2000K (2 000 000 ? )Place the resistor on the little foam mat.Place the probes (red and black) on each of the resistor’s terminals You should get a reading:1Scale: 2000K: Only a 1 on the left: the circuit is open: No readingSolution: check the connections (if still no reading, the resistor is more than 2000000?) 000Scale 2000K You get a reading, however the first, second or all digits are 0’sGet a more precise reading by selecting the next smaller scale (200K)00.3Scale 200K: You get a reading, however the first, second or all digit are 0’sGet a more precise reading by selecting the next smaller scale (20K)0.27Scale 20K You get a reading, however the first, second or all digit are 0’sGet a more precise reading by selecting the next smaller scale (2000 ?).273Scale 2000 Reading: 273 ? The resistance is 1Scale 200 : Only a 1 on the left: No reading : the scale chosen is too low. This scale (200 ?) measures resistance up to 200 ?. ................
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