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Resistors are used in various genuine life applications to carry out tasks that include: restricting the current that goes through a section of a circuit, presenting a voltage drop in a circuit, producing heat and the defense of elements of a circuit. It is crucial to compute the resistance of resistors so that the electrical circuits produced utilizing them will carry out in the manner that their producer wanted them to. If the wrong resistance/resistor is used then delicate parts that need just a fairly percentage of current may be ruined.

All resistors have a level of tolerance. This is to enable for flaws in the manufactured things. It was determined through experimentation that all of the resistors that were used in this experiment were within their tolerance variety with the exception of R4 (See Table 1). This resistor had a nominal value of 1600 ohms and a tolerance of +/ -5%. This means that this resistor ought to have had a value within the range of 1520-1680 ohms, however the actual resistance was discovered to be 1798 ohms.

It is possible that this might have been because of a manufacturing fault or a labelling error.

The overall anticipated resistance was figured out by utilizing the series and parallel resistor laws and the resistance values of the different parts of the circuit. The tolerance variety for the circuit was predicted to be in between 1847.3-2319.2 ohms. Through experimentation the real total resistance for the circuit was 2216.62 ohms, this worth was within the forecasted variety.

- The actual resistance value of part 1 was 263.26 ohms; this was within the anticipated variety (271.36-245.51 ohms).
- The actual resistance worth of part 2 was 1764.26 ohms; this was within the forecasted range (1664.24-1846.36 ohms).
- The real resistance value of component 3 was 2216.62 ohms; this was within the forecasted variety (2319.20 and 1847.3 ohms).
- The real resistance of the resistors was found by utilizing a multimeter. Some organized mistake may have taken place in this experiment if the multimeter was not adjusted correctly throughout screening.

Temperature fluctuations may have caused inconsistencies in this experiment. The reason why resistance occurs is that a metal consists of lattice of atoms that each has a shell of electrons. The metal is a conductor because the electrons are free to dissociate from their parent atoms and travel through the lattice. When a voltage is applied the electrons drift from one side of the metal to the other. In real material imperfections scatter the electrons resulting in resistance. Temperature is able to affect resistance because temperature causes the atoms to vibrate more strongly creating even more collisions and further increasing the resistance.

The aim of the experiment was to compare the predicted and actual resistance in the circuit of resistor combinations in series and parallel. The results of this experiment found that the series and parallel resistor laws were reasonably good indicators of the “real world” values of resistance for circuits that contained resistors in series and parallel. One example of this was that the total resistance of the circuit made was found to be 2216.62 ohms which was within the predicted range (this predicted range was calculated by using the upper and lower tolerance values for the resistors used in the circuit. From the data obtained it can therefore be seen that all three resistor laws stated in the Background section of this report are quite useful in calculating theoretical values for the resistance of circuits in series and parallel that are close to the “real world” values.

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- Storen, A and Martine, R. (2000) Nelson Physics VCE Units 3 and 4. Nelson Publishing: Sydney. (pp 221-226)