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Resistor Markings - Alpha Numeric & Color Codes


Three methods of resistor markings are predominant - color coding, numerical value coding and three-digit symbol coding. MIL-PRF-55342 assigns part numbers using alpha-numeric coding. Tolerance, temperature, package style and failure rate are integrated into some numbering schemes.

When I posted a recommendation for new uses for the color codes on the RF Cafe Smorgasbord feature, I invited visitor inputs. They are presented at the bottom of the page.

 
Color Coding
(3-Band and 4-Band Resistors)
Color 1st
Significant
Digit
2nd
Significant
Digit
3rd
Significant
Digit
(if used)
Multiplier Tolerance Failure Rate Level
(% per 1000 hours)
None         ±20%  
Silver       0.01 ±10%  
Gold       0.1 ±5%  
Black 0 0 0 1    
Brown 1 1 1 10  ±1% M = 1.0%
Red 2 2 2 100  ±2% P = 0.1%
Orange 3 3 3 1000 (=1k)   R = 0.01%
Yellow 4 4 4 10k   S = 0.001%
Green 5 5 5 100k    
Blue 6 6 6 1000k    
Violet 7 7 7      
Gray 8 8 8      
White 9 9 9      

3-Band Example

4-Band Example
6 - 2 - 3 - Silver
62 * 103 Ω, 10%
62 * 1000 Ω, 10%
62 kΩ, 10%

Radial lead resistor drawing - RF Cafe
 

1 - 9 - 6 - 0 - Red
196 * 100 Ω, 0.1% Failure Rate
196 * 1 Ω, 0.1% Failure Rate
196 Ω, 0.1% Failure Rate

Radial lead resistor drawing - RF Cafe
 


Numerical Value Coding

4 - 4 - 2 - 2
442 * 102
442 * 100 Ω
44 200 Ω
44.2 kΩ
Radial lead resistor drawing - RF Cafe
 

3-Digit Symbol Coding

 (1%)

A = 100, B = 101, C = 102, D = 103, E = 104, R = 10-1, S = 10-2

Example:

  1.00 Ω,     01S
  12.1 Ω,     09R
  165 Ω,      22A
  4.32 MΩ,   62E
Symbol
01 100
02 102
03 105
04 107
05 110
06 113
07 115
08 118
09 121
10 124
11 127
12 130
13 133
14 137
15 140
16 143
Symbol
17 147
18 150
19 154
20 158
2 162
22 165
23 169
24 174
25 178
26 182
27 187
28 191
29 196
30 200
31 205
32 210
Symbol
33 215
34 221
35 226
36 232
37 237
38 243
39 249
40 255
41 261
42 267
43 274
44 280
45 287
46 294
47 301
48 309
Symbol
49 316
50 324
51 332
52 340
53 348
54 357
55 365
56 374
57 383
58 392
59 402
60 412
61 422
62 432
63 442
64 453
Symbol
65 464
66 475
67 487
68 499
69 511
70 523
71 536
72 549
73 562
74 576
75 590
76 604
77 619
78 634
79 649
80 665
Symbol
81 681
82 698
83 715
84 732
85 750
86 768
87 787
88 806
89 825
90 845
91 866
92 887
93 909
94 931
95 953
96 976
 

A = 100, B = 101, C = 102, D = 103, E = 104, R = 10-1, S = 10-2

Example:

  2%,    1.00 Ω,  S01
  5%,    1.00 Ω,  S25
  10%,  1.00 Ω,  S49
  5%,    510 Ω,   A42
  10%,  820 kΩ,  D60
2%
Symbol
01 100
02 110
03 120
04 130
05 150
06 160
07 180
08 200
09 220
10 240
11 270
12 300
13 330
14 360
15 390
16 430
17 470
18 510
19 560
20 620
21 680
22 750
23 820
24 910
5%
Symbol
25 100
26 110
27 120
28 130
29 150
30 160
31 180
32 200
33 220
34 240
35 270
36 300
37 330
38 360
39 390
40 430
41 470
42 510
43 560
44 620
45 680
46 750
47 820
48 910
10%
Symbol
49 100
50 120
51 150
52 180
53 220
54 270
55 330
56 390
57 470
58 560
59 680
60 820


Here are the RF Cafe visitor responses to an invitation I made for suggested uses of the color code, or for different versions of the mnemonics used to remember the number-color relationships.

OK, since people have requested the politically incorrect mnemonic that I was taught in high school electrical vocational classes, here it is:

          Bad Boys Rape Our Young Girls But Violet Gives Willingly
also    Bad Boys Rape Our Young Girls Behind Victory Garden Walls


Does the non PC mnemonic you learned involve a YL named Violet? The Boy Scout mnemonic I learned way back when was " Better Be Right Or Your Great Big Venture Goes West - Get Some Now". A very early form of PC I guess.

Kevin A., Virginia

Note: Get Some Now refers to tolerance - Gold = 5%, Silver = 10%, None = 20%

Hi Kirt,

Indeed, color codes will fade away. Being colorblind I do not really care, however. You might want to know the color code mnemonic in Dutch:

Zij Bracht Rozen Op Gerrits Graf Bij Vies Grauw Weer.

black = zwart
brown = bruin
red = rood
orange = oranje
yellow = geel
green = groen
blue = blauw
purple = violet
gray = grijs
white = wit


(Approximate translation: she brought roses on Gerrits grave during dirty gray weather)

I am curious about the English version, that is supposed to be politically incorrect.

With kind regards,  Hugo K.,  the Netherlands.

Try this: Bad Beer Rots Our Young Guts But Vodka Goes Well – get some now

Troy Z., MT

Yo Kirt:

I’m sure I’m not the first to point out that the black box should be a brown one for your phone number. I learned the color code at age 9….not to date myself too much. I used to be able to read the capacitor and inductor color codes but I forgot those!

I’ve seen a total lack of analog Engineering skills from recent hires. If it doesn’t have a keyboard, then what is it???? Even component level digital skills are poor. Also, a shocking lack of troubleshooting skills. Broke? Replace the whole thing! The Engineering community needs an old fashioned mentor/apprentice program before the old guys retire; like me!

Rfcafe.com forever!

See ya,  Neil

Bye Bye Rosie, Off You Go, Bristol Via Great Western.

Clean and easy for a railroad fan to remember.

Joe B., Senior Project Engineer

We could color code our Social Security #’s …………….. NOT!

73,  John

Hi Kirt,

Your point on the color code is well taken. I'm 41 and I wasn't too far into my career when it 'disappeared' as SMT technology took over. I recently ran into it again and saw that it is alive and well in specifying wire color, especially with military standards (MIL-STD-681).

I found myself repeating that old politically incorrect mnemonic (bad
boys.....) again. ;-)

Regards, Roy A.
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