Parallel circuits for beginners (2024)

Electronic circuits are divided into two types based on the combination of circuits: parallel circuits and series circuits.

When all components are connected using a parallel combination called a parallel circuit. In a parallel circuit, components are arranged so that there are multiple pathways for the flow of electric current or in a parallel circuit two components share two common nodes. The parallel circuit is also called a current divider because the voltage is equal across each element, but the current is not equal.

This article will go into great detail about parallel circuits, their structure, and characteristics.

Table of Contents

Parallel circuits

In electronic circuits, the components are arranged in different combinations, the parallel combination is one of them.

The circuit is called a parallel circuit when components are connected in parallel combination. If components share two common nodes, they are parallel.

The node is nothing just an electrical junction between two or more components. Let’s see an example.

In the above circuit, components are connected in parallel as they share two or more nodes. You can also see there is more than one path for the current to flow.

The current from the positive terminal of the battery will flow to R1, R2, R3, and R4. So there are four paths for the current to flow.

We can say,

The circuit having a different path for current to flow is called a parallel circuit. The voltage remains the same and the current varies in parallel circuits.

In other words, in a parallel circuit, each connected component has its separate branch, and all the branches are connected to the same voltage points.

In the below circuit, you can see all the components are connected to one voltage source and there are different paths for current flow.

The current starts flowing from the positive terminal of the battery, when it arrives at the node, a current chooses which branch to travel through and gets back to the negative terminal of the battery.

Characteristics

Understanding the fundamentals of electronics and designing a circuit requires an understanding of the essential traits of parallel circuits.

Let’s discuss the characteristics of parallel circuits.

1. Constant voltage

One defining feature of a parallel circuit is that the voltage across each component remains constant. This feature is because of the same voltage source with which each branch is connected.

Whether it’s resistors, capacitors, or other devices, they all experience the same voltage in a parallel configuration. When there are ‘n’ number of components in the circuit, the voltage is equal.

V_S = V_1 = V_2………….= V_n

Where VS is the applied voltage and, V_1, V_2, and V_n are the voltages across different components.

2. Variable current

While the voltage remains the same, the current in the parallel circuit varies. Since each branch functions independently, different currents can flow through various channels.

If you see the above circuit, there are different branches and current is flowing through it.

One of the main benefits of parallel circuits is their flexibility, which permits the independent operation of individual components.

Let’s say there are ‘n’ number of resistors and they are connected in parallel combination. The total current across the circuit is given by

I_T= I_1 + I_2 +……………….+ I_n

So here I_T represents the total current and, I_1, I_2, and I_n are the currents flowing in each resistor.

3. Equivalent resistance

The equivalent resistance, or total resistance (Req), of a parallel circuit, is less than the smallest individual resistance in the circuit.

The total or equivalent resistance Req of a parallel circuit is found using the reciprocal of the sum of the reciprocals of the individual resistances.

So to calculate the equivalent resistance of parallel connection we have a formula,

1/R_eq= 1/R_1 + 1/R_2 + 1/R_3

If the n number of resistors are connecting then,

1/R_eq= 1/R_1 + 1/R_2 +………….. + 1/R_n

Examples

Up till now, you have understood what is a parallel circuit and how it works. Now it’s time to know how can be the current in the circuit calculated.

Let’s use examples for better understanding.

Example no. 1

Consider the circuit that has two resistors that are connected in parallel across a 10V voltage source.

The voltage across each resistor is the same in the parallel circuit so

V_S = V_1 =V_2 =10

To find the total current in the circuit, we have to find the equivalent resistance. The equivalent resistance of parallel circuits is equal to

1/R_eq = 1/R_1 + 1/R_2

1/R_eq = 1/10Ω + 1/20Ω

1/R_eq = 0.1Ω + 0.05Ω

1/R_eq = 0.15Ω

R_eq = 1/0.15Ω

R_eq = 6.7Ω

Now using Ohm’s law total current in the circuit is equal to

I_T =V_S/R_eq

I_T = 10/6.7

I_T = 1.5A

The current in each resistor is

I_1 = V_S/R_1

I_1 = 10/10

I_1 = 1A

Current in resistor two,

I_2 = VS/R2

I_2 = 10/20

I_2 = 0.5A

Now if you add both currents it will be equal to the total current. This is how we find the total current and current flowing in each resistor in the parallel combination.

Example no. 2

Let’s consider another circuit with a parallel connection of resistors.

In the above circuit, we have four resistors that are connected in parallel with the voltage source of 24V.

Let’s find the total current of the circuit that is flowing. For this, we have to find equivalent resistance.

1/R_eq = 1/R_1 + 1/R_2 + 1/R_3 + 1/R_4

1/R_eq = 1/10 + 1/20 + 1/30 +1/40

1/R_eq = 0.1 + 0.05 + 0.033 + 0.025

1/R_eq = 1/0.208

R_eq= 4.8Ω

Now the total current in the circuit is…

IT=VS/Req

IT=24/4.8

IT=5A

We can also find current in each resistor and the sum of all current across the resistor will be equal to the total current. The current across resistor one is

I_1 = V_S/R_1

I_1 = 24/10

I_1 = 2.4A

Current in resistor two,

I_2 = V_S/R_2

I_2 = 24/20

I_2 = 1.2A

You can calculate the current for the remaining two resistors in the same way. That’s how we find current in parallel circuits.

Advantages

Here are some advantages of parallel circuits.

As the voltage across all components are same, it is essential for devices requiring a specific operating voltage.
If one component fails, the rest of the circuit continues to function normally.
Parallel circuits are suitable for complex systems requiring the independent operation of different components.
Adding more branches decreases the overall resistance, allowing more current to flow without increasing the voltage.
Less energy is lost as heat in the parallel circuit due to lower resistance.

Disadvantages

Along with advantages, there are also some disadvantages of parallel circuits. Let’s see what are the disadvantages.

Parallel circuits are more complex to design and maintain as they require more wires for connections.
A short circuit in one branch can lead to high current flow, damaging components or causing the circuit to fail.
In large-scale applications, it can be costly.

Conclusion

Parallel circuits play a crucial role in the world of electronics, offering a versatile and efficient way to organize and power various components.

The circuit in which components are connected in parallel is called a parallel circuit.

In parallel circuits, there are various paths for current flow. In other words, if components share two common nodes they are in parallel.

The voltage in a parallel circuit is the same across each component and the current flowing through each component varies.

In a parallel circuit, the total resistance, or equivalent resistance, is less than the circuit’s smallest individual resistance.

This was all about the parallel circuits, I hope it will be helpful.

Thank you and have a blessed life.