1203 words - 5 pages

Title: Resistors in Series and ParallelDate: 17/7/05Aim:The aim of this experiment is to compare the predicted and actual resistance in a circuit of resistor combinations in series and in parallel.Background:A resistor is an electrical component/device that has electrical resistance. Resistors can be used in electric circuits for protection of components, voltage division or current control. In an ideal resistor the resistance remains constant regardless of the applied voltage or current, or the rate of change in the current (Resistor, 2005, Wikipedia).Electrical resistance is a measure of the ability of an object to oppose the passage of an electric current. The electrical resistance of an electrical component can be found by using Ohm's law. Ohm's law states that the potential difference (voltage) between the ends of a conductor (e.g. a resistor) and the current flowing through the conductor are proportional at a given temperature (Storen & Martine, 2000, p221-226). This law can be written as: R=V .IThe SI unit used for electrical resistance is an ohm. An electrical device that has an electrical resistance of 1 ohm will cause a current of 1 amp to flow through it if a voltage of 1V is passed through it.From previous scientific research it has been determined that the general law for resistors in series is: Rseries = R1 + R2 + R3+RnIt has also been determined that the general law for resistors in parallel isRparallel =Hypothesis:From the formulas stated in the Background of this report it can be seen that the total resistance of resistors in series can be found by adding together the individual resistances of each component. It can also be seen that the total resistance of resistors in parallel can be found by adding together the individual reciprocals of each component's resistance and then taking the reciprocal.Predictions:By knowing the individual resistor values we can accurately determine the total resistance of resistor combinations. Please refer to the Results section of experiment for more detail.Materials:-Seven resistors-12v power pack-Multimeter-2 alligator clips-Small lengths of thin copper wire-Circuit test (bread) boardMethod:1.The circuit shown in Diagram 1 (see Results) was set up using the appropriate electrical components.2.The 12v power supply was turned on and set to 6v.3.The amperage, voltage and resistance of the three resistor combinations (see results) within the circuit were found, as well as the total amounts for the whole circuit by using the multimeter.4.The voltage and amperage of each resistor was then found by using the multimeter.Results and Calculations:Diagram 1: Circuit SetupTable 1: Resistor ValuesAll actual resistances obtained were within the relevant upper and lower tolerance values stated above except for the resistance obtained for R4.Prediction calculations:Total Resistance (Equivalent to Resistor Combination 3) (See Image 1)R total lower:= 1847.3 ohmsR total upper:= 2319.20 ohms(The actual value...

Get inspired and start your paper now!