How to read resistor color code
Hi friends, Understanding resistor color code is very important for designing an electronic circuit. If you are working on electronic you must know about resistor color code, either you are a student or a professional guy.
Why these Color (resistor color code) Bands are printed on Resistor?
I have already explained the construction of a resistor. Actually Resistors are very small component. A through hole resistor is around 6-7 mm size and Surface mount resistor is very small it is around 3-4 mm size so it is clear that manufacturer can’t write all information on component that’s why these Resistor color code developed. Printing color band is very much easy on small component. Even for surface mount resistor a different coding system developed which will explain later.
Decoding through hole resistor color code
Usually in a through hole resistor you will get 4 color bands. Each and every color code has its own value. This Resistor color code can be describe as given below table
Here out of four bands first two bands indicate two most-significant digits of the resistor’s value and third band is a weight value, which multiplies the two significant digits by a power of ten.
The Last band indicates the tolerance of the resistor. The tolerance means how much more or less the actual resistance of the resistor. On other hand you can understand it like accuracy of resistor because No resistor is made to perfection. For example, a 2kΩ resistor with 5% tolerance could be anywhere between 1.90kΩ and 2.10kΩ.
But before reading resistor color code put gold or silver band to right side otherwise your calculation will be wrong.
Here’s an example of a 4.7kΩ resistor with four color bands:
When decoding the resistor color code, consult a resistor color code table. For the first two color bands is for most significant value. yellow and violet to begin – which have digit values of 4 and 7 (47). The third band is red, which indicates that the 47 should be multiplied by 102 (or 100). So final value is 4.7KΩ.
You can also remember resistor color code table by remembering given mnemonic
“Big brown rabbits often yield great big vocal groans when gingerly snapped.”
Decoding surface-mount Resistor coding
In market SMD resistors are available in different packages like 0603, 0805. They’ll usually have three to four characters (numbers or letters) printed on top of the resistor.
If there are only numbers printed on the resistor it’s decoding is same as resistor color code system. Here first two digit is for the Most significant bit and the last digit is for multiplier
As shown in picture, resistors are printed 104, 105, 205, 751, and 754. The resistor marked with 104 is 100kΩ (10×104), 105 is 1MΩ (10×105), and 205 is 2MΩ (20×105). 751 is 750Ω (75×101), and 754 is 750kΩ (75×104).
Another Surface mount resistor coding system is E96, and it’s based on different coding system. E96 resistors will be marked with three characters – two numbers at the beginning and a letter at the end.
The two numbers tell you the first three digits of the value, by corresponding to one of the not-so-obvious values on this lookup table.
The letter at the end represents a multiplier:
|Y or R||0.01||B or H||10||E||10000|
|X or S||0.1||C||100||F||100000|
So a 01C is 10kΩ (100×100), 01B is 1kΩ (100×10), and 01D is 100kΩ. 85A from the picture above is 750Ω (750×1) and 30C is actually 20kΩ.
Hope that you have got a simple and important information about Resistor color code and now you will b able to read resistor value on your tips.
If you are planning to purchase some resistor for your coming project check it and don`t forget to share this with your friend.