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MECA Electronics Attenuators

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%  
Black0 0 0 1    
Brown1 1 1 10  ±1% M = 1.0
Red2 2 2 100  ±2% P = 0.1
Orange3 3 3 1000 (=1k)   R = 0.01
Yellow4 4 4 10k   S = 0.001
Green5 5 5 100k    
Blue6 6 6 1000k    
Violet7 7 7      
Gray8 8 8      
White9 9 9      
3-Band Resistance Example
(w/tolerance band)
3-Band Resistance Example
(w/tolerance & reliability bands)
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

You might also find resistors marked with 4 bands for resistance, where the first 3 bands are significant digits and the 4th band is the multiplier. 4,5 & 6-Band Resistor Color Code Calculator (Digi-Key) - RF CafeExample: A 20.5 Ω, 1% tolerance resistor would be marked as Red, Black, Green, Gold, Brown. Here is a handy-dandy resistor color band converter from Digi-Key.

 

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
01100
02102
03105
04107
05110
06113
07115
08118
09121
10124
11127
12130
13133
14137
15140
16143
Symbol
17147
18150
19154
20158
2162
22165
23169
24174
25178
26182
27187
28191
29196
30200
31205
32210
Symbol
33215
34221
35226
36232
37237
38243
39249
40255
41261
42267
43274
44280
45287
46294
47301
48309
Symbol
49316
50324
51332
52340
53348
54357
55365
56374
57383
58392
59402
60412
61422
62432
63442
64453
Symbol
65464
66475
67487
68499
69511
70523
71536
72549
73562
74576
75590
76604
77619
78634
79649
80665
Symbol
81681
82698
83715
84732
85750
86768
87787
88806
89825
90845
91866
92887
93909
94931
95953
96976
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
01100
02110
03120
04130
05150
06160
07180
08200
09220
10240
11270
12300
13330
14360
15390
16430
17470
18510
19560
20620
21680
22750
23820
24910
(5%)
Symbol
25100
26110
27120
28130
29150
30160
31180
32200
33220
34240
35270
36300
37330
38360
39390
40430
41470
42510
43560
44620
45680
46750
47820
48910
(10%)
Symbol
49100
50120
51150
52180
53220
54270
55330
56390
57470
58560
59680
60820

 

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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