+1 vote
by Epic (640 points)
I have a resistor with colored bands on it. How do I read these colors to find out its resistance value?

1 Answer

0 votes
by Mythic (1.5k points)
So you're staring at this little cylinder with some colored stripes on it, and you're like "How the heck do I know what resistance this thing has?" Well, my friend, those colors are the key to unlocking the mystery.

It's like a secret code or something. Each color represents a number or a multiplier value. By decoding those color bands, you can figure out the resistor's resistance rating in ohms. Pretty slick, huh?

Here's how it works: The first couple of color bands give you the first two digits of the resistance value. So if you see brown and green, that would be 15. Easy enough, right?

But then you get to the third band. That one tells you the multiplier, or how many zeroes to tack on to that first two-digit number. Red means you multiply by 100, so a brown-green-red resistor would be 15 x 100 = 1,500 ohms or 1.5 kilohms. Make sense?

If you see a gold or silver band, that's telling you the multiplier is a weird one - like 10^-1 for gold or 10^-2 for silver. Just think of those as shifting the decimal point to the left.

And that last band? That's the tolerance value. It lets you know how precise that resistance rating really is. Silver is 10%, gold is 5%, and so on.

Now, I know what you're thinking - "But Chris, how am I supposed to remember what all those colors mean?" Trust me, there are plenty of resistor color code calculators and charts out there to reference. Just punch in the colors, and it'll spit out the resistance value for you.

The real trick is making sure you're reading those bands in the right order from the end. Get that part mixed up, and you might think a 10K resistor is actually 1 ohm! Not a mistake you want to make in your circuits, am I right?

So there you have it - the secret language of resistor color codes. It's like a little puzzle you get to solve every time you need to know a resistor's value. Who said electronics couldn't be fun?
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