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:



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

  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



Fault Calculation - Symmetrical Components

For unbalance conditions the calculation of fault currents is more complex. One method of dealing with this is symmetrical components. Using symmetrical...

Fault Calculation - Per Unit System

Per unit fault calculations is a method whereby system impedances and quantities are normalised across different voltage levels to a common base.  By removing...

Getting Started with Patents

If you have a great idea or invent something the last thing you want is someone to steal the idea. One of the things you can do is protect the intellectual...

Battery Cars A to Z

Battery powered cars are a hot topic and widely debated. The pros, cons, issues and time frames can be talked about endlessly. An article by the Telegraph...

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...

Robotics - Home Innovations

We have a sister note to this (Robots - Interesting Video), in which I have posted some videos of interesting robots developed by commercial corporations...

Mobile Phones (Brick to Implant)

The mobile phone was born in 1973. They were the size of a brick and weighed a couple of kg, making them difficult to fit into your pocket. At a few thousand...

How to Size Power Cable Duct

Some colleagues had an issue earlier in the week on sizing conduits to be cast in concrete for some power cables . It became clear that none of us had...

Electric Motors

Collection of links to various places with useful motor information. I’ll try and return to the page every now and again to update it with any motor notes...

Electromechanical Relays

Electromechanical relays have been the traditional backbone of electrical protection systems.  While over recent years these have been replaced by microprocessor...

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