Resistors
How to read the color codes of the resistors and tips. (6/25/2006)
As the name indicates, a resistor is a resistance for al electrical circuit. There is two ways to determine the value of a resistance: by formula or by value.
To determine the resistance in a circuit, we need to know the value of the voltage (V) and the current (I), so the resistance = voltage / current ( R = V / I )
Another wat to know the value, is just reading the value. Some values are color coded, others are marked. Usually, resistors have four colored strips. Some precision resistors have five.
To identify the value of the resistor, you need to know and learn the value of each color to identify it.
Color Code
|
COLOR BLACK BROWN RED ORANGE YELLOW GREEN BLUE VIOLET GRAY WHITE |
1st 0 1 2 3 4 5 6 7 8 9 |
2nd 0 1 2 3 4 5 6 7 8 9 |
3rd (Multiplier) x 1 x 10 x 100 x 1,000 x 10,000 x 100,000 x 1,000,000 x 10,000,000 x 100,000,000 x 1000,000,000 |
Tolerance: 4th band
Gold +-%5, Silver +-10%, no color: +-20%
Using the previous table, we can read the value of this resistor: Red, Red, Orange, Gold. That means: 2, 2, x 1,000, +-5%.
So, we obtain: 22,000 +-5%. This is a 22K resistor with +-5% tolerance. The tolerance means the precision. 5% of 22,000 so this resistor may have 20,900 ohms or 23,100 ohms.
The surface mount resistors are easy to read, it should have three digits, the first one is the first digit, the second one is the second digit and the third one is the multiplier, so the resistors on this picture are 2.2K, 2.2K and 91K
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