Series Circuit

Series Circuit

In a series circuit each electrical circuit component is joined end-to-end in such a manner that there is only one possible path of current flow.

An electric circuit is the path of electric current, composed of conductors and conducting devices, including a source of electromotive force, such as a battery, that drives the current around the circuit. There are two basic types of connections in electric circuits: parallel and series. A series circuit is a circuit that contains components connected in series. That is, the devices or elements of the circuit are arranged in such a way that the entire current passes through each device without division or branching into parallel circuits.

A series circuit is one in which the current flows through the devices one after another. The total resistance in the circuit is equal to the sum of the resistance of each individual device (R = R + R + R +...) and current that flows through each device is the same as the total current in the circuit. The voltage drop across the circuit must equal the total voltage supplied by the electromotive force device (i.e., the battery).

In many circuits, fuses are used in series with other devices in the circuit for safety purposes. A fuse has a small metallic strip through which the current passes. If the current is too large, the strip melts and the circuit is opened. Another device, the circuit breaker, is also employed to do the same job. In a circuit breaker the current passes through a bimetallic strip. If the current is too high, the bimetallic strip bends and causes a switch to open the circuit. In this state no current passes until the switch is set and the bimetallic strip has cooled. The circuit breaker system is often employed since it can be reset and does not need to be replaced when the current exceeds the recommended magnitude.

Because there is only one path for the charges to move along in a series circuit, each component terminal end is connected to another componentüs terminal end. Thus, if the positive terminal end of one component is connected to the negative terminal end of another component, then there is no connection to another component at that same terminal. In this way the charges must move in sequence, from one component to the next. If one component in the circuit is broken, no charge will move through the circuit because it only has one path to travel. In a string of lights connected in series, when one bulb burns out the entire string goes dark because the circuit is broken and there is no other path for the current to follow.