Colour Code of Resistors: Chart, How to Read and Examples

Resistors are too small for printed numbers, so manufacturers paint coloured bands on them. Each colour encodes a digit; reading the bands in order gives the resistance in ohms and its tolerance, no instrument needed. This code is universal across makers and countries, and every technician and hobbyist reads it fluently.

Choosing wrongly has real costs: an LED burns, a timer mistimes, an amplifier distorts. The code also teaches compact number encoding, digits plus a multiplier, the same idea as scientific notation.

Key Concepts

• Digit colours: Black 0, Brown 1, Red 2, Orange 3, Yellow 4, Green 5, Blue 6, Violet 7, Grey 8, White 9. Memory line: Black Boys Race Our Young Girls But Violet Generally Wins.
• Multiplier: Same colours mean times 10 to that power: red is x100, brown x10, black x1. Gold means x0.1, silver x0.01.
• Tolerance: Gold plus-minus 5 percent, silver plus-minus 10 percent, none plus-minus 20 percent; brown 1 percent and red 2 percent on precision parts.
• Direction: Tolerance band goes last (on the right). Four bands: digit, digit, multiplier, tolerance. Five bands: three digits, multiplier, tolerance.

How It Works

1. Hold the resistor with the gold or silver band (or the separated band) on your right.
2. Read the first bands as digits, left to right: two digits for 4-band, three for 5-band.
3. Apply the multiplier band: multiply, or equivalently append that many zeros (gold or silver shifts the decimal left).
4. Apply tolerance: the true value lies within plus-minus that percentage of the nominal value.
5. A single black band means a 0 ohm jumper, a wire link used as a bridge on circuit boards.

Worked Example

(a) Yellow, Violet, Red, Gold. (b) Brown, Black, Black, Brown, Brown (5-band). Find values and ranges.

1. (a) Yellow 4, Violet 7 gives 47. Red multiplier x100 gives 4700 ohms (4.7 kilo-ohms).
2. Gold is plus-minus 5 percent: 5 percent of 4700 is 235, so the range is 4465 to 4935 ohms.
3. (b) Digits 1, 0, 0 give 100. Brown multiplier x10 gives 1000 ohms (1.0 kilo-ohm).
4. Final brown is plus-minus 1 percent, range 990 to 1010 ohms: a precision resistor, as 5-band parts usually are.

Common Misconceptions

• Misconception: Bands read equally well from either end. Correction: Backwards gives a wrong value; the tolerance band always marks the finishing end.
• Misconception: Gold can be a digit. Correction: Gold and silver are never digits, only multiplier (x0.1, x0.01) or tolerance.
• Misconception: A 4700 ohm resistor must measure exactly 4700. Correction: Tolerance promises a range; 4500 ohms is in spec for a 5 percent part.

Real-World Applications

• Repair work: Surviving bands identify burnt resistors for correct replacement.
• Hobby builds: LED, Arduino and audio projects all begin with reading values before soldering.
• Manufacturing: Bands survive heat and handling better than print on tiny cylinders.
• Exams and labs: A standard skill in Indian school practicals and electronics courses.

Digits, then multiplier, tolerance last: Yellow-Violet-Red-Gold speaks 4.7 kilo-ohms plus-minus 5 percent. Learn the colour order once and every resistor in the world states its value silently.