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Electrical Engineering

Ohm's Law

Relationship between voltage, current, and resistance

V = I R

Study tools

Save, share, export, or report this formula.

Source & review

Difficulty

Beginner

Read time

4 min

Prerequisites

Basic Electricity

Review statusNeeds review

Source

FormuLab initial formula library

Initial content draft pending verification against authoritative course or textbook sources.

Definition

Understanding the core concept

Ohm's Law describes the fundamental relationship between voltage (electrical pressure), current (flow of electrons), and resistance (opposition to flow) in an electrical circuit. Think of it like water flowing through a pipe: voltage is the water pressure, current is the flow rate, and resistance is how narrow the pipe is. Higher pressure or wider pipes mean more flow.

Variables & Units

Understanding each component

Symbol	Meaning	Units
$V$	Voltage (potential difference)	$V$
$I$	Current (electron flow)	$A$
$R$	Resistance	$Ω$

Real-World Applications

Where this formula is used in practice

Circuit Design

Calculate component values for desired circuit behavior

Power Systems

Analyze power distribution and energy consumption

Troubleshooting

Diagnose faults in electrical and electronic systems

LED Circuits

Calculate appropriate resistors for LED brightness control

Worked Example

Step-by-step calculation with real numbers

Problem

A circuit has a 12V battery connected to a resistor. If 0.5A of current flows through the circuit, what is the resistance value?

Given

V = 12 V

I = 0.5 A

R = ?

Solution

V = I R

R = \frac{V}{I}

R = \frac{12}{0.5}

R = 24 Ω

Final Answer

R = 24 Ω

Formula Guide

Info

DifficultyBeginner

Read Time4 min

PrerequisitesBasic Electricity

Tools

Source & review

StatusNeeds review

Last reviewedPending

Source

FormuLab initial formula library

Initial content draft pending verification against authoritative course or textbook sources.

Assumptions

• Use SI units unless the formula or course context states otherwise.
• Check notation, sign conventions, and applicability against your course material.
• Confirm variables and assumptions before using the formula in graded or professional work.