Components of an electrical circuit or electronic circuit can be connected in many different ways. The two simplest of these are called series and parallel and occur very frequently. Components connected in series are connected along a single path, so the same current flows through all of the components. Components connected in parallel are connected so the same voltage is applied to each component.

## What is a Series Circuit?Edit

A circuit composed solely of components connected in series is known as a series circuit.

The current in a series circuit goes through every component in the circuit.

In a series circuit, the current through each of the components is the same, and the voltage across the circuit is the sum of the voltages across each component. There is only one path in a series circuit in which the current can flow.

In a series circuit, every device must function for the circuit to be complete. One bulb burning out in a series circuit breaks the circuit.

The total resistance of resistors in series is equal to the sum of the individual resistances.

If the batteries are connected in series, the voltage of the Assembled battery Pack(We will call it ABP later) will be the sum of the individual batteries voltages. For example, a 12 volt car ABP contains six 2-volt batteries connected in series. Some vehicles, such as trucks, have two 12 volt batteries in series to feed the 24 volt system.

## What is a Parallel Circuit?Edit

A circuit connected completely in parallel is known as a parallel circuit.

In a parallel circuit, the voltage across each of the components is the same, and the total current is the sum of the currents through each component.

In parallel circuits, each light has its own circuit, so all but one light could be burned out, and the last one will still function.

If two or more components are connected in parallel they have the same potential difference (voltage) across their ends. The potential differences across the components are the same in magnitude, and they also have identical polarities. The same voltage is applicable to all circuit components connected in parallel. The total current is the sum of the currents through the individual components.

In a parallel circuit the voltage is the same for all elements.

The total resistance will always be less than the value of the smallest resistance.

If batteries are connected in parallel, the ABP's voltage will be the same as the batteries voltage but the current supplied by each battery will be a fraction of the total current. For example, if a ABP contains four batteries connected in parallel and delivers a current of 1 ampere, the current supplied by each battery will be 0.25 ampere. Parallel-connected batteries were widely used to power the valve filaments in portable radios but they are now rare. Some solar electric systems have batteries in parallel to increase the storage capacity; a close approximation of total amp-hours is the sum of all batteries in parallel.

## Real World Situation

Lights used light up in the advertisement poster boards are placed in series circuits. The doubled long electric lights used in office buildings and schools are parallel circuits. Devices like wireless keyboard, flashlight, and TV monitor use multiple batteries are usually of series circuits. Switches of electric lights are series circuits. Series and parallel circuits are important because they allow us design circuits for different scenarios and conditions.

## Word Problems

### Problem 1Edit

There are two parallel circuits. The first one with one resistor and the second one with two resistors, assuming all resistors has the same resistance. Which circuit has more total resistance? Depends on the value of individual resistance Circuit 1: R (Total) = R1/R1 Circuit 2: R (Total) = R1^2/R1+R1 If R1 = 1, R = 1^2/1+1 = 1/2 If R1 = 2, R = 2^2/2+2 = 1 If R1 = 3, R =3^2/3+3 = 3/2 Therefore, If R1<2, then Total resistance of Circuit 2 < Total resistance of Circuit 1 If R1=2, then Total resistance of Circuit 2 = Total resistance of Circuit 1 If R1>2, then Total resistance of Circuit 2 > Total resistance of Circuit 1

### Problem 2Edit

There are two series circuits. The first one with one resistor and the second one with two resistors, assuming all resistors has the same resistance. Which circuit has more total resistance? The second circuit, because individual resistances are the same, Circuit 1: R (Total) = R1 Circuit 2: R (Total) = R1 + R1 Therefore the second circuit will have more total resistance.

## Topic Reflection

The learning and understanding of this topic have improved my perception of the natural world in many ways. Electricity is used everywhere by everyone in this world and circuits are the basics of electricity in usage. I love technology and all the smartphones, tablets and computers are powered by electricity and consisted of electric circuits. Series and parallel circuits are found everywhere in these devices and their design affect the outcome of the devices' performance.