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



Multimeter

Multimeters are undoubtedly the most common item of electrical test equipment in use.  Often it is the first piece of equipment people will turn to when...

Resistors

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

Control Theory

Control theory looks at how systems work and are controlled from a mathematical view.  This note gives a brief introduction to some of the concepts – more...

Maxwell's Equations - Gauss's Electric Field Law

Gauss's Electrical law defines the relation between charge ("Positive" & "Negative") and electric field.  The law was initially formulated by Carl Friedrich...

Cable Sizing Software

When sizing cables nearly, everyone uses some form of software. This ranges from homespun spreadsheets to complex network analyses software. Each has its...

How Electrical Circuits Work

If you have no idea how electrical circuits work, or what people mean then they talk about volts and amps, hopefully I can shed a bit light.  I’m intending...

HTML Symbol Entities

HTML supports a variety of entity symbols which can be entered using either numbers or an entity name.  The number or name is preceded by the ‘&’ sign...

Earth Electrode Resistance

Earthing of electrical systems is essential for the correct functioning and the protecting of life and equipment in the event of faults.  The earth electrode...

LED Replacement Light Bulb

The inventor of the first visible light-emitting diode makes history again this year as it begins to show customers a 40-watt replacement GE Energy Smart...

Aluminium Windings - Dry Type Transformers

The other day I was talking to a colleague who is a building services consultant.  Despite regularly specifying dry-type/cast resin transformers he was...

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