Understanding Ohm's Law: A Comprehensive Guide

Ravikirana BRavikirana B
3 min read

Ohm’s Law is a fundamental principle in electronics that explains how voltage, current, and resistance are related. But numbers alone can confuse beginners. So, let’s understand this using a simple analogy — a water tank, a pipe, and a gate wall.


🧠 What is Ohm’s Law?

Ohm’s Law states:

V = I × R
where:

  • V = Voltage (in volts)

  • I = Current (in amperes)

  • R = Resistance (in ohms)

This formula tells us:

The current flowing through a circuit is directly proportional to the voltage and inversely proportional to the resistance.


💧 Water Tank Analogy

Imagine a water tank at a height with a pipe at the bottom.

  • The water pressure inside the tank = Voltage (V)

  • The rate of water flow through the pipe = Current (I)

  • Any narrowing of the pipe or gate control = Resistance (R)


🚪 Gate Wall Analogy – Resistance in Action

Now, place a gate wall (valve) in the pipe that can be opened or closed to control the water flow.

  • Fully open gate → low resistance → water flows freely → high current

  • Partially closed gate → medium resistance → reduced water flow → medium current

  • Almost closed gate → high resistance → very little water flows → low current

This is exactly how a resistor works in an electrical circuit.


🔄 Understanding the Relationship Between V, I, and R

Let’s break it down further using real examples.

📌 Case 1: Fixed Resistance, Increase Voltage

Voltage (V)Resistance (R)Current (I = V / R)
10V10Ω1A
20V10Ω2A
5V10Ω0.5A

🔎 Observation: When resistance is constant, increasing voltage increases current — like adding more water pressure.


📌 Case 2: Fixed Voltage, Increase Resistance

Voltage (V)Resistance (R)Current (I = V / R)
12V2A
12V12Ω1A
12V24Ω0.5A

🔎 Observation: When voltage is constant, increasing resistance decreases current — like tightening the gate in the pipe.


💡 Key Takeaways

  • Voltage (V) is like water pressure

  • Current (I) is like the flow rate

  • Resistance (R) is like a valve or gate controlling flow

  • Ohm’s Law connects them: V = I × R

The more pressure, the more flow.
The tighter the gate (more resistance), the less water can pass (less current).


0
Subscribe to my newsletter

Read articles from Ravikirana B directly inside your inbox. Subscribe to the newsletter, and don't miss out.

Written by

Ravikirana B
Ravikirana B

I’m Ravikirana B – an engineer driven by curiosity and clarity. I specialize in electronics, Python programming, and work across a range of technologies to build real-world solutions that blend hardware and software. I started Tech Shodhaka to share what I learn, simplify what I know, and spark curiosity in those who want to understand how tech actually works — especially in our own languages and ways of thinking. Here, you’ll find: 🔧 Electronics concepts explained with analogies (like water flow, gates, tanks) 🐍 Python-based tech insights and automation ideas ⚡ Real tech reflections from both theory and hands-on work 🌿 A touch of Kannada-English expression for wider reach I believe in making learning accessible, especially for students and self-learners from smaller towns like mine. If you’re someone who loves understanding “why” and “how”, Tech Shodhaka is for you. Let’s keep exploring, clearly and curiously. 🙌