Objectives

• To study current flow in series and parallel circuits.
• To study voltages in series and parallel circuits.
• Use Ohm’s law to calculate equivalent resistance of series and parallel circuits.

Introduction

Components in an electrical circuit are in series when they are connected one after the other, so that the same current flows through both of them. Components are in parallel when they are in alternate branches of a circuit. Series and parallel circuits function differently. You may have noticed the differences in electrical circuits you use. When using some decorative holiday light circuits, if one lamp burns out, the whole string of lamps goes off. These lamps are in series. When a light bulb burns out in your house, the other lights stay on. Household wiring is normally in parallel.

You can monitor these circuits using a Current and Voltage meters to see how they operate. One goal of this experiment is to study circuits made up of two resistors in series or parallel. You can then use Ohm’s law to determine the equivalent resistance of the two resistors.

Ohm's law relates quantities of voltage and current by resistance:  V(volts) = I(amps)×R(ohms)
where voltage is the potential difference (electric pressure) between two locations and current is the amount of charge flowing between those two locations. Resistance relates current and voltage, thought of as the resistance to flow of electricity.