parallel and series resistors in a circuit. Light bulbs in both series and parallel were also examined. As well as understanding the relationship between resistance,current and voltage in a circuit and how it relates to Ohm’s Law. This will be tested by using four different circuits connected in series and parallel combinations and tested theoretically and experimentally. The current and the voltage will be measured which will then be used to calculate the experimental resistance. The behavior of the light bulbs in both series and parallel will be examined as well. After conducting the experiment the percentage differences were found to be 0.43%, 4.8%, 2.8% and 1.8%, these results are low which is important since the errors in the experiment are supposed to be low. It is important to understand resistance, current and voltage and how it is shown in both parallel and series resistors in a circuit which makes this lab important. Introduction In this experiment the objective is to understand series and parallel circuits, learn how to calculate the equivalent resistance and then construct them in this lab. To understand the relationship between resistance, current and voltage you have to understand Ohm’s Law1 given mathematically as: V=IR(1)where V stands for voltage, I stands for current and R stands for resistance. There will be four circuits whose resistance will be determined experimentally and theoretically. There are differentways a circuit with a power supply can be arranged such as parallel, series and combinations of the two. In a series circuit there is a single path the current can flow meaning all parts of a series circuit have the same current. In a parallel circuit, each device has its own connection to the power supply and the current divides with some flowing through each parallel branch.