Capgo datalogger, data logger, datalogging and data logging.

  

Resistor Codes

 
 

Axial leaded resistors are generally marked with their value using one of the following color coding systems.

Sometimes the color bands can be confusing as sensible but different values can be read in each direction. For example red red brown brown can be 220 ohms(1%) or 1100 ohms (2%) although the bands are usually "left justified" to reduce the likelihood of being miss-read. If in doubt use a multimeter to check the value. Also, resistors are manufactured in standard values - so the color bands should correspond to one of those values - see below.

Some high precision resistors have their value, precision and temperature coefficient printed on the resistor body as the color bands can not adequately describe their properties. Alternatively some manufactures use a proprietary coding scheme for which you will need to consult the manufacture's data sheet to decode.

Surface mount resistors are not color coded, however the significant figures and multiplier are normally printed on the resistor as three or four digits.

Resistors come in standard values - referred to as the E ranges. The most common is the E12 range, but E6, E24 and E96 are also manufactured. The E value refers to the number of resistor value in a decade. For example in the E12 range there are 12 values between 10 and 100 ohms. The E6 range is a subset of the E12 range and the E12 range is a subset of the E24 range. The E24 range however is not a subset of the E96 range.

The temperature coefficient is a measure of a resistor's response to temperature change and is expressed in parts per million resistance change per one degree celsius temperature change (ppm/C or more commonly just ppm). Ideally the value should be zero, however this is never attained in practice. Standard low cost resistors typically have a temperature coefficient of 100-300 ppm, precision resistors 5-20 ppm and ultra high stability resistors <2 ppm. The very best resistors can achieve about a 0.2 ppm temperature coefficient. Resistors without a temperature coefficient band will generally have a high temperature coefficient.

 

E6 Range

100, 150, 220, 330, 470, 680, (1000 ....)

E12 Range

100, 120, 150, 180, 220, 270, 330, 390, 470, 560, 680, 820, (1000 ....)

E24 Range

100, 110, 120, 130, 150, 160, 180, 200, 220, 240, 270, 300, 330, 360, 390, 430, 470, 510, 560, 620, 680, 750, 820, 910, (1000 ....)

E96 Range

100, 102, 105, 107, 110, 113, 115, 118, 121, 124, 127, 130, 133, 137, 140, 143, 147, 150, 154, 158, 162, 165, 169, 174, 178, 182, 187, 191, 196, 200, 205, 210, 215, 221, 226, 232, 237, 243, 249, 255, 261, 267, 274, 280, 287, 294, 301, 309, 316, 324, 332, 340, 348, 357, 365, 374, 383, 392, 402, 412, 422, 432, 442, 453, 464, 475, 487, 499, 511, 523, 536, 549, 562, 576, 590, 604, 619, 634, 649, 655, 681, 698, 715, 732, 750, 768, 787, 806, 825, 845, 866, 887, 909, 931, 953, 976, (1000 ....)

The E96 range is generally only manufactured in precision (1%, <100ppm/°C or better) grade resistors.

E128 Range

100, 101, 102, 104, 105, 106, 107, 109, 110, 111, 113, 114, 115, 117, 118, 120, 121, 123, 124, 126, 127, 129, 130, 132, 133, 135, 137, 138, 140, 142, 143, 145, 147, 149, 150, 152, 154, 156, 158, 160, 162, 164, 165, 167, 169, 172, 174, 176, 178, 180, 182, 184, 187, 189, 191, 193, 196, 198, 200, 203, 205, 208, 210, 213, 215, 218, 221, 223, 226, 229, 232, 234, 237, 240, 243, 246, 249, 252, 255, 258, 261, 264, 267, 271, 274, 277, 280, 284, 287, 291, 294, 298, 301, 305, 309, 312, 316, 320, 324, 328, 332, 336, 340, 344, 348, 352, 357, 361, 365, 370, 374, 379, 383, 388, 392, 397, 402, 407, 412, 417, 422, 427, 432, 437, 442, 448, 453, 459, 464, 470, 475, 481, 487, 493, 499, 505, 511, 517, 523, 530, 536, 542, 549, 556, 562, 569, 576, 583, 590, 597, 604, 612, 619, 626, 634, 642, 649, 657, 665, 673, 681, 690, 698, 706, 715, 723, 732, 741, 750, 759, 768, 777, 787, 796, 806, 816, 825, 835, 845, 856, 866, 876, 887, 898, 909, 920, 931, 942, 953, 965, 976, 988

The E128 range is generally only manufactured in high precision (0.5%, 0.1%, 0.05%, <20ppm/°C) grade resistors.

Mathematical relationships

Successive values in a range are approximately related by e√10 or 101/e where "e" is the E Range number i.e. 6, 12, 24, 96 or 128.