Ohm

⚡ Electrical Resistance Tutorial

Understanding Ohm's Law and Resistor Color Codes

What is Electrical Resistance?

Electrical resistance is the opposition to the flow of electric current through a material. Think of it like water flowing through a pipe - a narrow pipe offers more resistance than a wide one. Resistance is measured in Ohms (Ω).

V = I × R

Voltage = Current × Resistance

I = V ÷ R

Current = Voltage ÷ Resistance

R = V ÷ I

Resistance = Voltage ÷ Current

Resistor Color Code System

Resistors use colored bands to indicate their resistance value and tolerance. Most common resistors have 4 or 5 bands.

 
 
 
 
 
 
 
Black: 0
 
Brown: 1
 
Red: 2
 
Orange: 3
 
Yellow: 4
 
Green: 5
 
Blue: 6
 
Violet: 7
 
Gray: 8
 
White: 9

Interactive Resistor Calculator

Select the colors to calculate resistance value

10 kΩ ±5%

How to Read Resistor Bands

4-Band Resistors:

  1. Band 1: First digit of resistance value
  2. Band 2: Second digit of resistance value
  3. Band 3: Multiplier (number of zeros or power of 10)
  4. Band 4: Tolerance (precision)

Example: Brown-Black-Orange-Gold = 1-0-×1000-±5% = 10,000Ω or 10kΩ with ±5% tolerance

💡 Memory Tip: "Big Boys Race Our Young Girls But Violet Generally Wins" (Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Gray, White)