Carbon resistors are most common in electronic equipment.They consists of a high grade ceramic rod or cone ( called the substrate on which is deposited a thin resistive film of carbon. The numerical value of their resistance is indicated by a colour code which consists of bands of different colors printed on the body of the resistor.The color used in this code and the digits represented by them are given in table below:
Usually the code consists of four bands.Starting from left to right.
The colour bands are interpreted as follows:
- The first band indicates the first digit in the numerical value of the resistance.
- The second band gives the second digit.
- The third band is decimal multiplier i.e,it gives the number of zeroes after the first two digits.
- The fourth band gives resistance tolerance.Its colour is either silver or gold.Silver band indicates a tolerance of ± 10 % ,a gold band shows a tolerance of ±5 %.If there is no fourth band ,tolerance is understand to be ± 20%.By tolerance ,means the posible variation from the marked value.For example ,a 1000 Ω resistor with a tolerance of ± 10 % will have an actual resistance anywhere between 900 Ω and 1100 Ω.
Five Band Color Code:
Certain precision resistors with tolerance of 2 %, 1 %, or less are generally color coded with five bands as shown in figure given below:
Begin at the band closest to one end.The first band is the first digit of the resistance value,the second band is the second digit,the third band is the third digit,the fourth band is multiplier ( number of zeroes after the third digit),and the fifth indicates the percent tolerance.Below table of resistor 5 band color code is given:
Watch video to clear your more concepts about resistor color coding: