Color Codes

A mostly electronics reference


Resistors and other components use a rainbow code for digits and multipliers:

black brown red orange yellow green blue violet gray white
             
             
             
             
             
             
             
             
             
             
0 1 2 3 4 5 6 7 8 9
There's some other stuff, like gold and silver for tolerances and for multipliers less than one. Later for those. (Maybe) Gray in resistors is called Slate in telephone cables.

Telephone cables come in two basic types.

Multipair telephone cables use this sequence:
color pair
 tip
ring
pr#
white-blue  
 
1
white-orange  
 
2
white-green  
 
3
white-brown  
 
4
white-slate  
 
5
red-blue  
 
6
red-orange  
 
7
red-green  
 
8
red-brown  
 
9
red-slate  
 
10
black-blue  
 
11
black-orange  
 
12
black-green  
 
13
black-brown  
 
14
black-slate  
 
15
yellow-blue  
 
16
yellow-orange  
 
17
yellow-green  
 
18
yellow-brown  
 
19
yellow-slate  
 
20
violet-blue  
 
21
violet-orange  
 
22
violet-green  
 
23
violet-brown  
 
24
violet-slate  
 
25

There are several styles of coloring that are all equivalent. The first pair, for instance, may have two solid colors (one blue wire and one white), or one solid and one with a "tracer", like white with a spiral blue stripe. Nowadays you're more likely to see both wires striped; white with a blue stripe is the "tip" conductor, and blue with a white stripe is the "ring" conductor.

With just a few wires, such as the telephone wiring in your house, solid colors are used:

tip ring sleeve *
                
                
                
                
green red yellow black
This scheme actually goes a little farther, to include blue, orange, white, slate (gray), brown and violet. But that's only ten colors, and you can't wire a whole continent with that. Before I get into the grand scheme for multipair cables, a bit more on the above: "tip/ring/sleeve" refer to the parts of the plugs used on switchboards (which ought to be called plugboards or jackboards, I suppose). The tip/ring pair is the talk pair, the two wires that actually come into your house. The sleeve designation is local to the telephone exchange, and at your house the third wire is just ground, if it's there at all. The fourth wire was long ago used for low-voltage AC to light up your "Princess" phone, before modular connectors. Note, however, that if you have two-line wiring, then the yellow and black wires are the tip/ring talk pair for the second line.

Cross-reference between the single-color codes and the multipair codes:
(10/02: Thanx to Blair Alper for pointing out a discrepancy)

1st pair tip green white/blue
ring red blue/white
2nd pair tip black white/orange
ring yellow orange/white
3rd pair tip
white/green
ring
green/white
4th pair tip
white/brown
ring
brown/white

Old-time radio wiring

Ground Black     
Plate, B+ Red     
Screen grid Blue     
Bias, control grid Yellow     
Heaters Green     
Thanx to Ted Zatesio W1XO for the last couple of details.

Electrical wiring

Ground Green  
Neutral White  
Hot anything else              

Traffic Lights

Green      Go Go Go Vroom
Yellow      Squeeze the Lemon
Red      Bite the Tomato

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