(a) Colour code for fixed resistors
The colour code for fixed resistors is given in table.
Colour |
Significant Figures |
Multiplier |
Tolerance |
| Silver | – | 10-2 | ±10% |
| Gold | – | 10-1 | ±5% |
| Black | 0 | 1 | – |
| Brown | 1 | 10 | ±1% |
| Red | 2 | 102 | ±2% |
| Orange | 3 | 103 | – |
| Yellow | 4 | 104 | – |
| Green | 5 | 105 | ±0.5% |
| Blue | 6 | 106 | ±0.25% |
| Violet | 7 | 107 | ±0.1% |
| Grey | 8 | 108 | – |
| White | 9 | 109 | – |
| None | – | – | ±20% |
For a four-band fixed resistor (i.e. resistance values with two significant figures): yellow-violet-orange-red indicates 47 kΩ with a tolerance of ±2%
(Note that the first band is the one nearest the end of the resistor)
For a five-band fixed resistor (resistance values with three significant figures): red-yellow-white-orange-brown indicates 249 kΩ with a tolerance of ±1%
(Note that the fifth band is 1.5 to 2 times wider than the other bands)
(b) Letter and digit code for resistors
Another way of indicating the value of resistors is the letter and digit code shown in Table.
Resistance Value |
Marked as: |
| 0.47 Ω | R47 |
| 1 Ω | 1R0 |
| 4.7 Ω | 4R7 |
| 47 Ω | 47R |
| 100 Ω | 100R |
| 1 kΩ | 1 K0 |
| 10 kΩ | 10 K |
| 10 MΩ | 10 M |
Tolerance is indicated as follows: F = ±1%, G = ±2%, J = ±5%, K = ±10% and M = ±20%
Thus, for example,
R33M = 0.33 Ω ± 20%
4R7K = 4.7 Ω ± 10%
390RJ = 390 Ω ± 5%
| Read More Topics |
| Electric current and quantity of electricity |
| Standard symbols for electrical components |
| Electrical / electronic system block diagram |
| Power and signal transmission |
