Resistors, How to decode the resistance fom the color bands.

1. Feb 18, 2005

cyeokpeng

OK, I know this is a stupid question, but I just plainly forgot how to decode the value of the resistance of standard resistors from the color coding. I know the last band is soemthing to do with tolerance of the resistance values, but what is the value of the tolerance related to a certain color, I am still not sure. During the lab experiment or project, I usually ignore such things because there are labels in the compartments containing the resistors..
Can anybody help me. Thanks.

I

2. Feb 18, 2005

brewnog

http://xtronics.com/kits/rcode.htm should tell you everything you need, it didn't take 2 seconds of Googling, but then it's always easier to ask someone else!

Bad Boys Ravage Only Young Girls, But Violet Gives Willingly.

(Black Brown Red Orange Yellow Green Blue Violet Grey White.)

3. Feb 18, 2005

Janus

Staff Emeritus
You know, I could never figure how those mnemonic sentences are susposed to be easier to remember than just remembering the order in the first place.

What is so hard about remembering , Black, Brown, six colors of the spectrum in order, Grey, White? I mean, the order of the middle six colors is obvious, isn't it?

4. Feb 18, 2005

brewnog

Well, if you put it like that, easy peasy!

Then all you need to remember is Black and Brown, then "Richard Of York Gave Battle In Vain", then Grey and White, and then you just have to remember to forget about Indigo!

Simple! :tongue2:

5. Feb 18, 2005

Averagesupernova

There is no indigo in resistor bands.

Bad beer rots our young guts but vodka goes well.

6. Feb 18, 2005

Janus

Staff Emeritus
Again, why do people need a mnemonic to remember the order of the spectrum? Just visualize the colors and it's obvious what order they should go in.

To me, its more difficult to remember the the mnemonic. (I'd probably have to visualize the spectrum and recreate it from that, and what would be the point?)

Last edited: Feb 18, 2005
7. Feb 18, 2005

Integral

Staff Emeritus
Perhaps that is why he said 6 colors of the rainbow,,, I would say there aint no indigo in the rainbow either!

8. Feb 18, 2005

cepheid

Staff Emeritus
I think that's old school. Nowadays it's Roy G. Biv

Edit: Janus makes a good point. How hard is it to remember? It's not like red is going to be succeded by green. There's a natural progression.

9. Feb 19, 2005

brewnog

Yeah, I was kinda taking the piss with the Richard Of York thing.

10. Feb 19, 2005

cyeokpeng

Wow, Ok thanks a lot everybody, sorry too many replied, I have to thank all of you in a group, but that doesn't mean I feel less appreciated.
Thanks a lot for all you help again. All the information here you all provided is very useful. Finally, I know how to find resistance so as not to mix them up while doing my project design on breadboard.

11. Feb 19, 2005

DaveC426913

Well, I learned something new. I didn't know they went in ortder. We were just taught the order, never the pattern. So, black, brown, 6 colours, grey, white.

Though it doesn't say anything about the tolerances.

BTW, the missing Indigo is correct. There is no indigo in the rainbow either. Newton was just hot for the number 7, so he made it up.

12. Feb 19, 2005

Averagesupernova

I can't believe we're piing and moaning about which way to remember resistor color bands. Can't we remember it the way we want? Believe me when I tell you there are people out there going to school for electronics who have long forgotten the colors of the rainbow and the order they go in. Plus they would have to learn to put black and brown on the front and gray and white on the end. It is easier in the end to remember the poem about Violet being a whore. To tell you the truth, I never gave it a thought that they even matched the rainbow. I remembered the poem and after a short time I simply remember for instance that yellow is 4 and etc.

We can't say that there is no indigo any easier than we can say there is no red. All colors are simply our eyes reaction to the various frequency of the radiation. Indigo is just as much a part of the spectrum as red. If we can see it, it is there. We don't consider it a primary color but it is still there. I do see the point though. There are 3 primary colors in light and 3 primary colors in pigment for a total of six. Most people consider yellow being the only one different in pigment and the other 2 are the same as light. The truth is that all three are different.

13. Feb 19, 2005

cyeokpeng

Different people have different way of remembering things, we cannot force the way we want to remember things becuase each individual is different. Some people learn things faster by having pictorial imagination in his/her mind and these group of people finds it easier to recall the colors of the rainbow since from young they were taught that or even seen a rainbow before. Other people have the ability to remember phrases or poems, so nmemonics will be a better strategy for such groups of people to remember the color bands of the resistors. So it is a matter of preference or ease of usage.
Do you all agree?

14. Feb 20, 2005

NoTime

A PC version of the color code mnemonic.

Tolerance codes - band usually slightly wider than digit bands.
None - 20%
Silver - 10%
Gold - 5%
Red - 2%
Brown - 1% Normally has an additional digit band