At the base of any electrical engineering student or anyone in the electronics field is a thorough understanding of electric circuits. At the foundation of all electric circuits are series and parallel circuits.
Circuits are at the heart of our modern life, powering everything from our smartphones to the light bulb in our study lamps. Whether you’re an engineering student or just curious about how electricity flows, understanding series and parallel circuits is foundational. In this article, we’ll dive into how series and parallel circuits function, explore their differences, and solve some example problems. By the end, you’ll have a clearer understanding of the basics and function of these two types of circuits and hopefully, will kickstart your journey into electronics.
Before we get started, this article will require at least a basic knowledge of some electrical components. If you don’t have that, rest easy, just quickly check out our article on the basic electrical components and get back to this.
Now that you have that, Let’s get into it!
What Are Series and Parallel Circuits?
Series Circuits
In a series circuit, components like resistors, capacitors, or light bulbs are connected end-to-end in a single loop. This means that electricity flows through one component before moving to the next, sort of like cars moving on a one-lane road.
There are a few characteristics that series circuits posses. These are:
Same Current: The current (I) flowing through every component is the same in a series circuit.
Voltage Split: The total voltage (V) across the circuit is split among the components based on their resistance.
Single Path: If one component fails, the entire circuit breaks because as we said, its a one-way flow.
Remember your primary school days where you connect a battery, switch, and a bulb (sometimes several bulbs) in a loop. if a single bulb is removed from this circuit, it breaks. This is a prime example of a series circuit.
Now that we understand that, let’s look at a few equations that are used to calculate different magnitudes in a series circuit.
Series Circuit Equations:
Total Resistance: \( R_{\text{total}} = R_1 + R_2 + R_3 + \dots \)
Total Voltage: \( V_{\text{total}} = V_1 + V_2 + V_3 + \dots \)
Current: \( I = \frac{V_{\text{total}}}{R_{\text{total}}} \)No matter the complexity of the circuit, the above equations will always hold true for series circuits.
That’s enough of series circuits, let’s delve into parallel circuits.
Parallel Circuits
Unlike the series circuit, components in a parallel circuit are connected across multiple paths, so each component has its own independent branch. This setup ensures that electricity can flow through more than one route.
The parallel circuit has the following defining characteristics:
Current Splits: The total current is divided among the branches based on their resistance.
Same Voltage: The voltage across each branch in a parallel circuit is the same.
Multiple Paths: If one component fails, the rest of the circuit continues to work.
Perhaps the biggest example of a parallel circuit will be your house’s electrical system. Here you start to gain an inshight into their advantages. When a swtich or light bulb in your home get’s burnt out, no other appliences are effected.
The equations that we use to calculate various magnitudes on a parallel circuit are the following:
Parallel Circuits Equations:
Total Resistance: \( \frac{1}{R_{\text{total}}} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} + \dots \)
Total Voltage: \( V_{\text{total}} = V_1 = V_2 = V_3 \)
Total Current: \( I_{\text{total}} = I_1 + I_2 + I_3 + \dots \)
The above are the fundamental equations used to calculate different properties within the parallel circuit.
It is very important to know when to and when not to use each respective circuit.
Imagine designing an electrical system for a car or a home. Should you connect components in series or parallel? Your choice will impact how the system functions, how much energy it consumes, and its reliability. Understanding these circuits helps you make smart, practical decisions.
Let’s solve some example problems to further ground this newly attained knowledge.
Example Problems
Problem 1: Series Circuit
Question: A series circuit has three resistors: \( R_1 = 5 \, \Omega, \quad R_2 = 10 \, \Omega, \quad R_3 = 15 \, \Omega. \) If the total voltage supplied is 12V, what is the current flowing through the circuit?
Step-by-Step Solution:
- Find Total Resistance:
\( R_{\text{total}} = R_1 + R_2 + R_3 = 5 + 10 + 15 = 30 \, \Omega. \)
- Calculate Current:
Using Ohm’s Law \(\left( I = \frac{V}{R} \right)\):
\( I = \frac{V_{\text{total}}}{R_{\text{total}}} = \frac{12}{30} = 0.4 \, \text{A} \)
Answer: The current flowing through the circuit is 0.4 A.
Problem 2: Parallel Circuit
Question: A parallel circuit has two resistors: \( R_1 = 6 \, \Omega, \quad R_2 = 12 \, \Omega. \) The total voltage supplied is 24V. What is the total current flowing through the circuit?
Step-by-Step Solution:
- Find Total Resistance:
Using the parallel resistance formula:
\( \frac{1}{R_{\text{total}}} = \frac{1}{R_1} + \frac{1}{R_2} = \frac{1}{6} + \frac{1}{12} = \frac{2}{12} + \frac{1}{12} = \frac{3}{12} = \frac{1}{4} \)
Therefore, \( R_{\text{total}} = 4 \, \Omega. \)
- Calculate Total Current:
Using Ohm’s Law \(\left( I = \frac{V}{R} \right)\):
\( I = \frac{V_{\text{total}}}{R_{\text{total}}} = \frac{24}{4} = 6 \, \text{A}. \)
Answer: The total current flowing through the circuit is 6 A.
In conclusion
Understanding series and parallel circuits is essential for anyone studying electronics, engineering, or physics. By breaking down the concepts, equations, and practical examples, we’ve shown how these circuits differ and how to solve common problems.
