Common Resistor
Resistors are color coded for easy reading. Imagine how many blind technicians there
would be otherwise.
To determine the value of a given resistor look for the gold or silver tolerance band
and rotate the resistor as in the photo above.(Tolerance band to the right). Look at the
1st color band and determine its color. This maybe difficult on small or oddly colored
resistors. Now look at the chart and match the "1st & 2nd color band" color
to the "Digit it represents". Write this number down.
Example:
- First color is red which is 2
- Second color is black which is 0
- third color is yellow which is 10,000
- Tolerance is silver which is 10%
Therefore the equation is:
2 0 x 10,000 = 200,000 Ohms
- Tolerances
- Gold= 5%
- Silver=10%
- None=20%
|
Color Code |
| 1st. & 2nd Color Band |
Digit it Represents |
-----Multiplier----- |
 BLACK |
0 |
X1 |
 BROWN |
1 |
X10 |
 RED |
2 |
X100 |
 ORANGE |
3 |
X1,000 or 1K |
 YELLOW |
4 |
X10,000 or 10K |
 GREEN |
5 |
X100,000 or 100K |
 BLUE |
6 |
X1,000,000 or 1M |
 VIOLET |
7 |
Silver is divide by 100 |
 GRAY |
8 |
Gold is divide by 10 |
 WHITE |
|
Now look at the 2nd color band and match that color to the same chart. Write this
number next to the 1st Digit.
The Last color band is the number you will multiply the result by. Match the 3rd color
band with the chart under multiplier. This is the number you will multiple the other 2
numbers by. Write it next to the other 2 numbers with a multiplication sign before it.
Example : 2 2 x 1,000.
To pull it all together now, simply multiply the first 2 numbers (1st number in the
tens column and 2nd in the ones column) by the Multiplier. |
Tolerance Explanation
Resistors are never the exact value that the color codes indicate. Therefore
manufacturers place a tolerance color band on the resistor to tell you just how accurate
this resistor is made. It is simply a measurement of the imperfections. Gold means the
resistor is within 5% of being dead-on accurate. Silver being within 10% and no color band
being within 20%. To determine the exact range that the resistor may be, take the value of
the resistor and multiply it by 5,10, 0r 20%. That is the number that the resistor may go
either way.
Example: A 1,000 Ohm resistor with a gold band maybe any value between 950 to 1050
Ohms.
Example: A 22,000 Ohm resistor with a silver band maybe any value between 19,800 and
24,200 Ohms.
FAQ
Just a few common questions to help you out.
1) Which side of the resistor do I read from?
The Gold or Silver band is always set to the right, then you read from left to right.
Sometimes there will be no tolerance band -- Simply find the side that has a band closest
to a lead and make that the first band.
2) Sometimes the colors are hard to make out. How do I make certain what the value of
the resistor really is?
Occasionally the colors are jumbled or burnt off. The only way to read it then is with
a multi-meter across the leads
3) How do I remember this sequence of colors?
Remember the color codes with this sentence: Big Brown Rabbits Often Yield Great Big Vocal Groans When Gingerly Slapped.
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