Ohm's Law Explained Simply
How do engineers know which resistor to use? I discovered Ohm's Law — and it's simpler than you'd think!
What is Ohm’s Law and why is it so important? ⚡
In my previous LED project, I learned that I needed a resistor to protect my LED. But then I had a question:
🤔 How do engineers know which resistor to use?
That’s when I discovered Ohm’s Law!
What I explain in the video
What Voltage, Current, and Resistance mean
- Voltage (V) is the push from the battery — measured in Volts
- Current (I) is how much electricity flows — measured in Amps (mA for small stuff)
- Resistance (R) is how much something slows the flow — measured in Ohms (Ω)
How Ohm’s Law works
The magic formula is:
V = I × RThat means: Voltage = Current × Resistance
You can rearrange it to find any one if you know the other two:
- I = V ÷ R (find the current)
- R = V ÷ I (find the resistance)
How to calculate current flow and find the correct resistor value
If I have a 9V battery and an LED that needs 2V and 20mA, I can figure out the resistor I need:
- Voltage left for the resistor: 9V − 2V = 7V
- Current I want: 20mA = 0.02A
- Resistance = 7V ÷ 0.02A = 350Ω
So I’d pick a 330Ω or 470Ω resistor — close enough! ✅
Try the interactive lab!
I built an Ohm’s Law LED Lab where you can slide the battery voltage, pick different resistors, choose LED colors, and see the current flow in real time. There’s even a button that picks a safe resistor for you!
Why Ohm’s Law matters
Ohm’s Law is one of the most important concepts in electronics because it helps us design safe and reliable circuits instead of guessing. Whether you’re building with Arduino, robotics, or just experimenting, knowing how to calculate the right resistor saves your components from burning out.
If you’re learning Arduino, electronics, robotics, or STEM, this is a great place to start!
🚀 Follow my learning journey on Nitvi Talks!