1. ELECTRONICS 1
(FPELC01/ELC111T)
Resistor color coding

2. Resistor color codes
Because carbon resistors are small, they are
color coded to mark their resistance (R) value
in ohms.
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3. Tolerance
The tolerance of a resistor is the maximum
difference between its actual value and the
required value and is generally expressed as a
plus or minus percentage value.

4. For example
A 1kΩ 20% tolerance resistor may have a
maximum and minimum value of:
Maximum Resistance Value
1kΩ or 1000Ω + 20% = 1,200Ω's
Minimum Resistance Value
1kΩ or 1000Ω - 20% = 800Ω's
Then a 1kΩ 20% tolerance resistor may
have a maximum value of 1200Ω's and a
minimum value of 800Ω's resulting in a span
of some 400Ω's!!.

5. Resistor color codes conts.
Start reading color codes from Left to Right
with the larger width tolerance band oriented
to the right side indicating its tolerance.

6. The Standard Resistor
Color Code Chart.

7. Example
Yellow, Violet, Red, Silver
= 4, 7, 2 = 4 7 x 102 = 4700Ω or 4k7 10%.
What is the value of the following resistor and
the tolerance?
Red, Violet, Gold, Gold
Answer: 2.7Ω 5%

8. Example
What is the value of the following resistor and
the tolerance?
Answer: 2700Ω or 2.7kΩ 0.25%

9. Exercise
Resistor
First
colour
Second
colour
Third
colour
Fourth
colour
3,9MΩ 2%
680Ω 1%
0,47Ω 10%
66 Ω 5%
8,2k Ω 5%
Fill in the colour codes for the following resistors:

10. Answer
Resistor
First
colour
Second
colour
Third
colour
Fourth
colour
3,9MΩ 2% Orange White Green Red
680Ω 1% Blue Grey Brown Brown
0,47 Ω 10% Yellow Violet Silver Silver
66 Ω 5% Blue Blue Black Gold
8,2k Ω 5% Grey Red Red Gold

11. Examples
Resistor Tolerance 1st band 2nd band 3rd band 4th band 5th band
3M65 Ω 5%
12k5 Ω 0, 1%
28k7 Ω 1%
9k31 Ω 2%
60.4 Ω 0, 5%

12. Answer
Resistor Tolerance 1st band 2nd band 3rd band 4th band 5th band
3M65 Ω 5% Orange Blue Green Yellow Gold
12k5 Ω 0, 1% Brown Red Green Red Violet
28k7 Ω 1% Red Grey Violet Red Brown
9k31 Ω 2% White Orange Brown Brown Red
60.4 Ω 0, 5% Blue Black Yellow Gold Green

13. Preferred resistor values: E12,
etc.
Because it is not possible to stock all possible
values of resistances in a shop or component
store, preferred values have been chosen to
represent a usable spectrum of values.
Depending on the accuracy required,
resistances are available in 12 values for every
decade (between 1 and 10, 10 and 100, 100
and 1000 etc.) called the E12 series, 24 values
for every decade, called the E24 series, and
48, 96 etc.

14. E12, etc conts
The E12 series would cover any
possible value of resistance, if the
resistors have a tolerance of 10%, the
E24 series 5%, and the E96 series
1%, etc. The E12 resistor series must
be memorised.
E12 10 12 15 18 22 27 33 39 47 56 68 82

15. Examples
19847Ω
20348 Ω
148223Ω
9.0356 Ω
61 Ω
Fill in the closest E12 preferred resistor values
for the following:

16. Answers

17. Chips Resistors
A Surface Mount Resistor, or Surface Mount
Device [SMD]. Also refer to the Table of Resistor
Chip Sizes.
100 10Ω
232 2.3kΩ or
2300Ω

18. Class work
Determine the resistance of chip resistors with the
following coded values:
Coded values 103 3302 1R8 474 1002
Resistance
value

19. Answers
Coded values 103 3302 1R8 474 1002
Resistance
value
10kΩ 33kΩ 1.8Ω 470kΩ 10kΩ