Resistor Code

The electronic color code is used to indicate the values or ratings of electronic components, very commonly for resistors, but also for capacitors, inductors, and others. A separate code, the 25-pair color code, is used to identify wires in some telecommunications cables.

Resistor Color Code Chart

Band Color Options Band #1 Possible Band #2 Possible Band #3 Possible Multiplier Value For Band 3 Band #4 Value Tolerance Black 0 1 1 Brown 1 1 1 10 ±1% Red 2 2 2 100 ±2% Orange 3 3 3 1,000 Yellow 4 4 4 10,000 (±5%) Green 5 5 5 100,000 ±0.5% Blue 6 6 6 1,000,000 ±0.25% Violet 7 7 10,000,000 ±0.1% Gray 8 8 100,000,000 ±0.05% (±10%) White 9 9 1,000,000,000 None 20% Silver 10% Gold 5%

Resistor Color Code Information

The resistor color code is a long standing standard in both the electronics and electrical industries, indicating the value of resistance of a resistor. Resistance is measured in ohms and there is a foundation for it called Ohm's Law. Each color band represents a number and the order of the color band will represent a number value. The first 2 color bands indicate a number. The 3rd color band indicates the multiplier or in other words the number of zeros. The fourth band indicates the tolerance of the resistor +/- 20%, 10% or 5%. In most cases, there are 4 color bands. However, certain precision resistors have 5 bands or have the values written on them, refining the tolerance value even more. There is no standard (TANS) however, for the 5th band. From one manufacturing company to another, the 5th band may indicate 2%, 1%, 1/2% or even closer, according to their own standards. Color bands are usually found on resistors that have a wattage value of 1/8 to 2 watts; though it is rare, there are some 5 watt resistors that are banded. There are also some capacitor that are color-coded. 

Resistor color-coding

To distinguish left from right there is a gap between the C and D bands.

• band A is first significant figure of component value (left side)
• band B is the second significant figure (Some precision resistors have a third significant figure, and thus five bands.)
• band C is the decimal multiplier
• band D if present, indicates tolerance of value in percent (no band means 20%)

REFERENCE:
en.wikipedia.org/wiki/Electronic_color_code
http://www.csgnetwork.com/resistcolcalc.html