Resistor Color Code

Resistor Color Code

• Usually, a resistor's value in ohms is indicated by several colored bands on the resistor's body.
• Each integer from 0 to 9 is represented by a color. The table below shows which colors represent these integers.

Integer	Color
0	Black
1	Brown
2	Red
3	Orange
4	Yellow
5	Green
6	Blue
7	Violet
8	Gray
9	White

• Two other colors (silver and gold) are also part of the resistor color code, but they have special meanings. Instead of simply representing numbers, these two colors represent tolerances ratings. In particular, gold represents a 5% tolerance, and silver represents a 10% tolerance. We often write this as ±5% or ±10%. (The expression ±5% is read as "plus or minus five percent." Similarly, ±10% is read as "plus or minus ten percent.") Finally, a tolerance of ±20% is represented by no colored band at all. 

Tolerance	Color
±5%	Gold
±10%	Silver
±20%	None

Reading a Resistor's Value

• Now that you know what the individual colored bands stand for, let's see how to put them all together to find a resistor's value.
• Usually, a resistor's value in ohms is indicated by four colored bands on the resistor's body.
• The first three bands of the color code give the resistor's nominal value.
  • The first two colored bands represent the first and second digits of the nominal value. The third band represents the number of zeroes following those first two digits.
  • Example: If the first three bands are yellow-violet-red, then the nominal value is 4700 ohms, or 4.7 kilohms. That's because yellow stands for 4, violet stands for 7, and red stands for 2. (So the red band tells you to add two zeroes after the 4 and the 7.)
• The fourth band (or tolerance band), gives the percentage variation from the nominal value that the actual resistance may have.
  • Example: If the four bands are yellow-violet-red-gold, then we saw above that the nominal value is 4700 Ω, or 4.7 kΩ. But you would not expect the resistor's actual value to be exactly 4700 Ω. It might actually be a bit higher or lower. The gold band is the manufacturer's way of assuring you that the actual value lies within 5% of the nominal value.