6 band resistor calculator
| Colour | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | ×1 | — |
| Brown | 1 | ×10 | ±1% |
| Red | 2 | ×100 | ±2% |
| Orange | 3 | ×1k | — |
| Yellow | 4 | ×10k | — |
| Green | 5 | ×100k | ±0.5% |
| Blue | 6 | ×1M | ±0.25% |
| Violet | 7 | ×10M | ±0.1% |
| Grey | 8 | ×100M | ±0.05% |
| White | 9 | ×1G | — |
| Gold | — | ×0.1 | ±5% |
| Silver | — | ×0.01 | ±10% |
A six-band resistor is a five-band one with a temperature coefficient added. The sixth band gives drift in parts per million per degree Celsius: brown is 100 ppm, red 50, orange 15, blue 10. A 10 kΩ part at 50 ppm shifts 5 Ω over a 10 degree change.
How to read a 6 band resistor
Temperature coefficient matters far more often than people expect, because in a precision circuit it can dwarf the initial tolerance. A 0.1% resistor with a 100 ppm coefficient drifts by 0.1% over a ten-degree change, doubling its error before anything else has happened. That is why reference dividers and current shunts specify low-ppm parts, and why matched pairs on the same substrate are used where the ratio matters more than the absolute value. Both resistors then drift together and the ratio holds.
Questions
Temperature coefficient in ppm per degree Celsius. Brown is 100, red 50, orange 15, yellow 25, blue 10, violet 5.
0.01% per degree. Over a 20 degree swing that is 0.2%. Often larger than the resistor initial tolerance.
Only where absolute accuracy over temperature matters. For a pull-up or an LED resistor it is irrelevant.
To mark it as the coefficient rather than part of the value, and to show orientation.
For ratios, yes. Two resistors on the same substrate drift together, so the ratio holds even if both values move.