In the world of electronics Resistor plays a great roll. To know the value of a register there are Resistor Color Code chart. This color code is divided into 4 segments of a Resistor. From below image red color is brand A, violent is brand B, green is brand C & golden yellow is brand D. Brand C is also know as multiplier. Brand D is technically called Tolerance.
For example, a Resistor with bands of brown, orange, red, and gold will have first digit 1, second digit 3, followed by 2 zeros: 1,300 ohms. Gold signifies that the tolerance is ±5%.
Image Source: https://en.wikipedia.org