Notes

Resistors 

By on

Resistors
Resistors Resistors are electronic components that oppose the flow of current. Manufactured in various types and ranges they have a wide application to electronics.

The relationship between voltage and current in a resistor is given by Ohm's Law:

 myElectrical Equation

 

Identification and Values

Colour Code

When inspecting resistors, the given value is either printed on the body is can be determined from the resistor colour code.

Resistor Colour Code
Example

ResistorCode

Red(2)Blue(6)Green(5)
=2600000
=2.6 MΩ

The first two bands are the value and the third band is a decimal multiplier (10x).

Black Brown Red Orange Yellow Green Blue Violet Grey White

0

1

2

3

4

5

6

7

8

9

 

 

The fourth band give the tolerance:

Gold Silver None

5%

10%

20%

For precision resistors, sometimes a five band colour coding is used – first three bands are the value, fourth band is the multiplier and the fifth band is the tolerance.

Preferred Values

Resistors are manufactured and specified in a range of preferred values. 

The table shows the range of preferred values:

10 12 15 18 22 27 33 39 47 56 68 82

Note: to obtain full range, multiply table by 10X

Circuit Arrangements

For more information on circuit arrangements and how to work these out, please see the following note:

, ,

More interesting Notes:
Steven McFadyen's avatar Steven McFadyen

Steven has over twenty five years experience working on some of the largest construction projects. He has a deep technical understanding of electrical engineering and is keen to share this knowledge. About the author

myElectrical Engineering

comments powered by Disqus

View 2 Comments (old system)

  1. resistor's avatar resistor says:
    8/7/2012 7:58 PM

    There also exist 6 band resistors, where the 6th band often refers to the thermal coefficient. for more information on resistor color codes http://www.resistorguide.com/resistor-color-code

    • Steven's avatar Steven says:
      8/8/2012 12:59 PM

      Thanks for the information on the sixth band. Your site all about resistors is interesting; good luck with it.

Comments are closed for this post:
  • have a question or need help, please use our Questions Section
  • spotted an error or have additional info that you think should be in this post, feel free to Contact Us
Large Hadron Collider

The 27 km, Euro 6 billion  Collider lies on the border between France and Switzerland, took nearly 30 years to complete.  Some of the lofty goals for the...

What does N+1 mean?

The term 'N+1' relates to redundancy and simply means that if you required 'N' items of equipment for something to work, you would have one additional...

Occam's Razor

I was reminded of Occam's Razor while reading a book. It's quite a simple principal of logic which has stood the test of time and is accepted as central...

Cable Sheath and Armour Loss

When sizing cables, the heat generated  by losses within any sheath or armour need to be evaluated. When significant, it becomes a factor to be considered...

Motor Starting - Introduction

Motor starting and its associated problems are well-known to many people who have worked on large industrial processes. However, these things are, of course...

GE's Shingijutsu Factory

GE's latest thinking on product manufacturing is he Shingijutsu philosophy or Lean production system. They have started applying this at the Louisville...

Battery Sizing

This article gives an introduction to IEEE 485 method for the selection and calculation of battery capacity.

How to refer fault levels across a transformer

Over the past year or so I've been involved in on going discussions related to referring fault levels from the secondary of a transformer to the primary...

Resistors

Resistors are electronic components that oppose the flow of current.  Manufactured in various types and ranges they have a wide application to electronics...

Introduction to Current Transformers

Current transformers (CTs) are used to convert high level currents to a smaller more reasonable level for use as inputs to protection relays and metering...

Have some knowledge to share

If you have some expert knowledge or experience, why not consider sharing this with our community.  

By writing an electrical note, you will be educating our users and at the same time promoting your expertise within the engineering community.

To get started and understand our policy, you can read our How to Write an Electrical Note. 

Footer
(click here to extend)
Copyright (c) 2026 myElectrical