Contents
Daily Dose 012 | Electrical Circuits
How do you find the Current in the branch of an Electrical Circuit?
I’ll admit, I’m not the biggest fan of problems that ask me to find the current in the branch of an electrical circuit.
In fact, one of my biggest obstacles in adopting the Other Disciplines strategy was seeing Electrical Circuits on the specifications.
As a Mechanical background, working with Electricity felt akin to trying to handwrite a letter with my left hand – but the reality was, I, as well as anyone else, can get “dangerous enough” to perform well in any subject.
In this lesson, we jump in to a problem type that is covered within the subject of ELECTRICAL CIRCUITS, specifically, diving into how you can find the current in the branch of an electrical circuit.
Key Definition
What is ELECTRICAL CURRENT?
ELECTRICAL CURRENT is any movement of electric charge carriers.
Measured in amperes (amps), ELECTRICAL CURRENT is the time rate of flow of electric charge, in the direction that a positive moving charge would take and having magnitude equal to the quantity of charge per unit time.
The conventional symbol for current is I and is foundational in OHM’S LAW and much of ELECTRICAL CIRCUITS.
The Process
How can you find the current in the branch of an electrical circuit?
Electrical circuits are all around us.
From the device you’re currently using to the lights that illuminating your surroundings – just as blood flows through our veins, electricity flows through these circuits.
This electric flow, called CURRENT, is fundamental to our understanding of circuits.
Most, as did I, view circuits and current flow as something that is beyond them – but it isn’t and as with any of the other complex problem type that will be on the FE Exam, we will break it down into a simple, streamlined, repeatable process.
- Step 1: Identify the Type of Circuit
- Series Circuit: There’s only one path for the current to follow. The current remains the same throughout the circuit.
- Parallel Circuit: Multiple paths exist for the current. Current splits among the different branches but the voltage across each branch remains the same.
- Step 2: Use Ohm’s Law
- V = I × R
- Step 3a: For Series Circuits
- Rtotal = R1 + R2 + …
- Itotal = Vsource / Rtotal
- Step 3b: For Parallel Circuits
- = 1/R1 + 1/R2 + …
- For branch 1 – I1 = Vsource / R1
- For branch 2 – I2 = Vsource / R2
- Step 4: Utilize Kirchhoff’s Laws
- Kirchhoff’s Current Law (KCL): The sum of currents entering a junction equals the sum leaving it.
- Kirchhoff’s Voltage Law (KVL): The sum of the electrical potential differences (voltage) around any closed loop or circuit is zero.
- Step 5: Analyzing Given Information
- P = I × V
Carefully read through the problem statement and look over the diagram that is provided. Are you looking at a Series circuit or a Parallel circuit? Or a combination of both?
Ohm’s law is the trusty map that links voltage (V), current (I), and resistance (R) in an equation:
The total or equivalent resistance Rtotal is the sum of all individual resistances:
Using Ohm’s Law, find the total current in the circuit:
The current remains the same in every branch in a series circuit.
The inverse of the total or equivalent resistance (1/Rtotal) is the sum of the inverses of all individual resistances:
Using Ohm’s Law, find the current for each branch:
…and so on.
When circuits get complex, Kirchhoff’s circuit laws are essential.
Sometimes, the problem might provide more than what meets the eye. Maybe you’re given the power consumed or other related parameters. Remember the power formula:
This can be an alternate route to finding your current.
Understanding how to find the current in the branch of an electrical circuit might appear intricate initially, but they operate on a set of well-defined principles. Think of each problem as a puzzle, waiting for you to piece it together.
This is the general blueprint that will help you tackle a range of problems involving current flow through electrical circuits. Adapt and expand upon these steps as needed based on specific nuances found within the problem statement.
And with all of that being stated, check out the video and see how we can go about solving this type of problem in the most efficient manner.
As always, we are here to help, Prepineer
