The four-band code is used for measuring low precision resistors with five to twenty percent tolerance. Here’s a brief guide that describes how to read resistor color codes.
Classifying the value of 4-band resistor color code is quite easy since there are only a few simple rules to remember.
So, let’s try to understand the rules, and the significance of all those codes.
In four-band code, first 2 represent the most significant digits; as given in the above table, if a resistor has blue and brown as the first 2 bands, the most significant digits will be 6 and 1 (61).
The other band indicates the ‘multiplier exponent’, indicating you to add zeros next or multiply the power of ten.
Considering band is red (2), you’ll have to multiply by 10^2 and hence, the value of would be 61 x 100 = 6100ohm (6.1Ω). If the multiplier exponent band is silver, move the decimal point 2 places to left (divided by 100) and if its gold, move to left by position (divided by 10).
If the resistor has one more band, it’s the quality band, which signifies the tolerance level.
Tolerance band is usually placed away from others and color code is assigned to each tolerance: Silver band represents 10% and Gold band represents 5% tolerance.
The 5 band resistor color code is used for measuring high-quality resistors with 2 percent or lower tolerance. Rules are similar as above, but only difference is that first 3 bands represent the value and 4th band is the multiplier and 5th band represents the tolerance level.
Occasionally, you may come across blue colored resistors that are made up of a fire-resistant material. These are usually put into usage only in automotive circuits.
We hope that now you’ve learned how to read resistor color codes without breaking a sweat, and we recommend you also to take a look at our guide on capacitor codes.