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Standard EIA Decade Resistor Values Table

The Electronic Industries Association (EIA), and other authorities, specify standard values for resistors, sometimes referred to as the "preferred value" system.  The preferred value system has its origins in the early years of the last century at a time when most resistors were carbon-graphite with relatively poor manufacturing tolerances.  The rationale is simple - select values for components based on the tolerances with which they are able to be manufactured.  Using 10% tolerance devices as an example, suppose that the first preferred value is 100 ohms.  It makes little sense to produce a 105 ohm resistor since 105 ohms falls within the 10% tolerance range of the 100 ohm resistor. The next reasonable value is 120 ohms because the 100 ohm resistor with a 10% tolerance is expected to have a value somewhere between 90 and 110 ohms. The 120 ohm resistor has a value ranging between 110 and 130 ohms. Following this logic, the preferred values for 10% tolerance resistors between 100 and 1,000 ohms would be 100, 120, 150, 180, 220, 270, 330 and so on (rounded appropriately); this is the E12 series shown in the table below.

The EIA "E" series specify the preferred values for various tolerances.  The number following the "E" specifies the number of logarithmic steps per decade.  The table below is normalized for the decade between 100 and 1,000.  The values in any decade can be derived by merely dividing or multiplying the table entries by powers of 10.  The series are as follows:

E3     50% tolerance (no longer used)
E6     20% tolerance (now seldom used)
E12   10% tolerance
E24     5% tolerance
E48     2% tolerance
E96     1% tolerance
E192   0.5, 0.25, 0.1% and higher tolerances

While the "E" preferred value lists are the best way to insure one is stocking the optimum number of values for a given tolerance, a word of caution is in order with respect to what is actually available in the marketplace and certain real world practices.  For instance, the E48 list is often used as a stock list for 1% resistors for inventory control (48 values per decade rather than 96), but this practice leaves "holes" or gaps in one's stock not covered by tolerance overlap, an undesirable practice in a prototype lab (less of an issue to the digital designer than to an analog circuit designer).  The use of the E48 list for inventory control of 1% resistors works out well because every value on the E48 list just happens to also appear on the E96 list; the holes are thus symmetrical and easily filled by acquisition of one of the other 48 values per decade being omitted from stock.  However, this is not always the case as can be seen by comparing the E24 and E96 lists.  Nevertheless, many manufacturers make every single value on the E24 list in 1% tolerance even though the practice makes little mathematical sense (think about the obvious tolerance overlap between the 120 and 121 values for instance).  Stocking only the E24 series in 1% will result in less symmetrical holes in stock than the practice of stocking only the E48 series.  In any event, one should be aware of these practices to avoid confusion.

Standard EIA Decade Values Table (100 to 1,000 Decade)
E6E12E24E48E96E192
100100100100100100
101
102102
104
105105105
106
107107
109
110110110110
111
113113
114
115115115
117
118118
120
120120121121121
123
124124
126
127127127
129
130130
132
130133133133
135
137137
138
140140140
142
143143
145
150150150147147147
149
150150
152
154154154
156
158158
160
160162162162
164
165165
167
169169169
172
174174
176
180180178178178
180
182182
184
187187187
189
191191
193
200196196196
198
200200
203
205205205
208
210210
213
E6E12E24E48E96E192
220220220215215215
218
221221
223
226226226
229
232232
234
240237237237
240
243243
246
249249249
252
255255
258
270270261261261
264
267267
271
274274274
277
280280
284
300287287287
291
294294
298
301301301
305
309309
312
330330330316316316
320
324324
328
332332332
336
340340
344
360348348348
352
357357
361
365365365
370
374374
379
390390383383383
388
392392
397
402402402
407
412412
417
430422422422
427
432432
437
442442442
448
453453
459
E6E12E24E48E96E192
470470470464464464
470
475475
481
487487487
493
499499
505
510511511511
517
523523
530
536536536
542
549549
556
560560562562562
569
576576
583
590590590
597
604604
612
620619619619
626
634634
642
649649649
657
665665
673
680680680681681681
690
698698
706
715715715
723
732732
741
750750750750
759
768768
777
787787787
796
806806
816
820820825825825
835
845845
856
866866866
876
887887
898
910909909909
920
931931
942
953953953
965
976976
988

  Also see our reference pages on Mil Spec Resistor Data and 1% Resistor Color Codes.


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02-08-02
Last 10-20-10