电阻阻值和电阻颜色的关系
Resistor color code is a system of color code which is imprinted physically in resistors ; used to indicate the values and specifications of the resistor.
A four or five color bands is usually imprinted on resistor’s outer surface which indicates the resistance value , Resistance tolerance and temperature coefficient of the resistor.
The color code is imprinted in bands in the outer layer of resistors as shown in the image:
resistors with color code
Each color band on the resistor color code have their own significance or value.
A chart with the value of each color band is shown below:
resistor color code
To read a Color Code imprinted on a resistor we need to follow the following steps:
1. Take the resistor in hand with the color band with either color “Gold” or “Silver” or the color band with the largest spacing towards the right side of you as shown on the figure below:
resistor with color bands
2. Now Write down the value of Band “A” and “B” in a copy or paper , for eg. if “A” is violet and “B” is red then the write down “72″.
3. Now multiply the value with the multiplier value of the band “C”. for eg. if “A” is violet , “B” is red and “C” is green then multiply “72″ with 10^5 which gives: 72 * 10^5. The value of the resistor is the Value thus obtained in ohms.
4. The fourth Band Signifies the tolerance of the resistor for eg: if “A” is violet , “B” is red , “C” is green and “D” is gold the actual value of the resistor is: 72 * 10^5 +/- 5% ohms.
Note: Sometimes resistors also have five bands as the color code in that case the first three bands signifies significant value the fourth one signifies the multiplier and the fifth band signifies it’s tolerance.
