PAGE 036 OF 150 · POWERING LEDS
Reading Resistor Colour Bands
Colour bands encode the digits and multiplier.
LED SYMBOLTriangle points from anode to cathode; the arrows show light leaving the part.
The colour code
Each colour stands for a digit: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9.
Four-band resistors
- Bands 1 and 2 are the first two digits.
- Band 3 is the multiplier, the number of zeros to add.
- Band 4 is tolerance: gold is 5 percent and silver is 10 percent.
Examples
- Orange, orange, brown, gold = 33 × 10 = 330 ohms, 5 percent.
- Brown, black, red, gold = 10 × 100 = 1 kilohm.
Five-band resistors use three digits, then a multiplier and tolerance. Confirm with a multimeter if unsure.
REMEMBER
The resistor sets the current, so the resistor sets the safety.Try it yourself
Sketch the circuit on paper first, calculate the values, then build it on a solderless breadboard using a low-voltage supply. Measure with a multimeter before you make anything permanent.
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