This document discusses resistor color coding. It explains that resistors have their resistance value and tolerance indicated by colored bands that are read from left to right. The first band represents the first digit, second band the second digit, third band is the multiplier, and fourth band is the tolerance. Examples are provided of calculating the resistance value and tolerance range of sample resistors based on their color bands. In conclusion, using the color band system allows easy identification of a resistor's resistance value.
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Overview
Conclusion / Review
Examples
Resistor Tolerance
Resistor Color Codes
Review: What is a Resistor?
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Review: What is a Resistor?
Resistors – circuit component that resist (limits)
the flow of electrons in an electrical circuit.
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Resistor Color Codes
• Resistors have their resistance value and tolerance shown by
colored bands.
• Read the resistor bands from the left-hand side.
• 1st band is the one closest to one of the ends.
• 4th band will have either gold, silver, or no color.
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Resistor Color Codes
• 1st band = 1st significant digit
• 2nd band = 2nd significant digit
• 3rd band = multiplier
• 4th band = tolerance
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Resistor Color Codes
Bright
Boys
Rise
Over
Your
Grades
By
Very
Good
Work
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Resistor Color Codes
Question: Why do we use color
coding in a resistor?
Ans.: For easier identification.
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Resistor Color Codes
1st band: orange 3
2nd band: white 9
3rd band: yellow 10,000
4th band: silver +/- 10%
Therefore:
39 x 10,000 = 39,000
39 kilo ohms +/- 10%
1st band: red 2
2nd band: green 5
3rd band: black 1
4th band: silver +/- 10%
Therefore:
25 x 1 = 39,000
25 ohms +/- 10%
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Tolerance
From the resistor value:
39 kΩ +/- 10%
The tolerance limits the
resistance to:
Minimum value:
39 kΩ - 10% = 35.1 kΩ
Maximum value:
39 kΩ + 10% = 42.9 kΩ
From the resistor value:
25 Ω +/- 10%
The tolerance limits the
resistance to:
Minimum value:
25 Ω - 10% = 22.5 Ω
Maximum value:
25 Ω + 10% = 27.5 Ω
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Tolerance
Question: Why does a resistor
have tolerance?
Ans.:
There is no perfect resistor with
an exact value.
Resistors are manufactured in
approximate values.
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Review & Conclusion
Review
• Calculate the resistance of the sample
resistors.
Conclusion
• You can calculate the resistance in a
resistor just by using the color bands.