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AIM: To get familiar with basic circiuts, resistors and their
colour codes as well as the instruments in the lab and there uses.
PROCEDURE 1: Using 5 different resistors, the colour codes were read and the results were recorded. Using the same 5 resistors, the results were checked using an ohmmeter scale that was taken using the multimeter the results were again recorded. The results were then placed in a table and compared.
RESISTOR NO. NOMINAL VALUE MEASURED VALUE PERCENTAGE
1 18000 +/-10% 17760 -1.3%
2 3300 +/- 10% 3660 +10.9%
3 1000 +/- 10% 1038 +3.8%
4 4700 +/- 10% 5060 +7.6%
5 2200 +/- 10% bad resistor
CONCLUSION 1: There was a difference between the nominal value and the measured value. All except resistor 2 and resistor 5 (which was bad) were within the tolerance band.
PROCEDURE 2: The power supply was set to give 3 volts. The multimeter with a voltage scale was then used to measure the exact voltage that power supply was supplying.
RESULTS: The multimeter read about 4-4.5 volts. And it was difficult to adjust the power supply to get the exact value of 3V on the multimeter.
CONCLUSION 2: The power supply scale is much less accurate than the multimeter scale.
PROCEDURE 3: A circuit was set up as in the diagram on the question paper attached. Using the 4 good resistors, each resistor was placed in the circuit separately. The current through each resistor was measured and recorded while using a 5V power supply. The resistance was then calculated using the formula: R=V/I.
RESISTOR NO. VOLTAGE
InVolts CURRENT RESISTANCE
1 5 0.28mA 17857.14
2 5 1.36mA 3676.47
3 5 4.76mA 1050.42
4 5 0.98mA 51020.04
RESISTOR NO. NOMINAL VALUE MEASURED VALUE CALCULATED
1 18000 +/-10% 17760 17857.14
2 3300 +/- 10% 3660 3676.47
3 1000 +/- 10% 1038 1050.42
4 4700 +/- 10% 5060 51020.04
CONCLUSION 3: All the values were within the tolerance band given except resistor 2 which was slightly over. The most accurate method would be using the ohmmeter because when using the calculating method the value of the voltage will not be accurate because of the power supply’s scale.
CONCLUSION 3 CONT’D: Also both the values for the current and the voltage will have will have to be accurate while in the ohmmeter it is only one value.
The fastest method would be reading the color codes but that is not really accurate, the resistor could even be bad an you would not know.
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Electromagnetism, Force, Electricity, Electronic test equipment, Measuring instruments, Electrical components, Electric heating, Resistor, Multimeter, Ohmmeter, Electrical resistance and conductance, Ohm
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