Bad Beer Rots Our Young Guts, But...

Listen while you read: Franz Ferdinand - Lucid Dreams

The Resistor color code: a thing of genius, but how to memorize it? Not sure how the resistor code was dreamed up or how old it is but I'm sure ever since its creation there have been thousands of ways of memorizing it. Despite the vast amount, an engineer need only memorize one to thrive in the electronic world. If you don't already have one memorized I would highly recommend this popular saying that I was taught my first year of college. The saying will help you memorize the order of each of the colors in the code and therefore help you remember the value of each of the colors on a resistor band.
The saying: Bad Beer Rots Our Young Guts, But Vodka Goes Well.
The colors: Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Gray, White.
The values: 0,1,2,3,4,5,6,7,8,9
Now, this color code is just for the first 2 to 3 bands which again, correspond to the 1st, 2nd and 3rd digits of the value in ohms. The 3rd and sometimes 4th band is the multiplier of the previous digits. So if the multiplier were to be orange simply add three zeros to the value: Red, Yellow, Blue, Orange would equal 246,000 ohms or 246 kohms.
The final band stands for the tolerance of the resistor. The tolerance is the percentage error that the measured resistance must lie between. So, if you have a gold banded resistor the tolerance is 5%. This means for a 1 kohm rated resistor the real resistance lies somewhere between 950 ohms and 1.5 kohms. The graphic below should help explain for those having trouble. There is even a 6th band which tells you temperature coefficient, the resistance of a resistor can change with temperature and sometimes the temperature coefficient is labeled on components that operate within a very small tolerance in extreme conditions.

Next post, I'll explain the coding for ceramic capacitors. No, I don't have nice little saying for that one, I just have it printed out and posted to my tool box. Make sure to leave a comment below and share your method for memorizing the color code. Stay Wired Up!
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mitchell said...

Great post! We literally just went over that stuff last night in class.

Kurf said...

Great Mitchell, are you a teacher or a student?

Anonymous said...

Just wanted to bring to your attention that your list of colors for resistor codes has green twice and is missing gray.
The article is clear and accurate but thought you might like to know about this minor discrepancy.

Kurf said...

Fixed as gray. Thanks!