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 Calculations - Introduction

Fault calculations are one of the most common types of calculation carried out during the design and analysis of electrical systems. These calculations...

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...

Power Transformers - An Introduction

One of the fundamental requirements of an alternating current distribution systems it to have the ability to change the magnitude of voltages.  It is more...

Operational Amplifier

The fundamental component of any analogue computer is the operational amplifier, or op amp. An operational amplifier (often called an op-amp,) is a high...

IEEE Winds of Change

IEEE TV has a part series of videos on wind power and it's implication. For a really good overview to the technologies and issues around wind power, these...

Cable Trumps

Bored at work and would rather be playing trump card game with you son. The next best thing (or not) maybe the online cable trump card game from AEI Cables...

What is Aircraft Ground Power

Ever wondered what kind of power an aircraft uses when parked at the airport stand. Normally the aircraft generates it own power, but when parked with...

Paths of Flight

GE have put together a time-lapse video shown flight take-off and landings at some airports. An interesting view:

Robots - Interesting Videos

The robot folding towels post below was interesting enough at the time to post a link.  Recently I’ve come across a couple of other interesting videos...

Paternoster Lifts

These lifts were first built in 1884 by J. E. Hall and called a paternoster ("Our Father", the first two words of the Lord's Prayer in Latin) due to its...

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