What is the primary purpose of a resistor color code chart?

• A. It identifies the resistance value and tolerance of resistors
• B. It lists color codes for wiring insulation
• C. It shows color codes for LED indicators
• D. It measures temperature coefficients of resistors

Answer: (A)

Reading resistor color codes is about translating the colored bands on a resistor into its electrical value. The chart maps colors to numbers and to how those numbers combine to form a resistance value.

The most common four-band code uses the first two bands for the significant digits, the third band as a multiplier (how many zeros to append), and the fourth band for tolerance (how accurate the value is). For example, a resistor with brown, black, red, and gold bands would be 10 × 100 = 1,000 ohms (1 kΩ) with a tolerance of ±5%. Some resistors use a five-band code where the first three bands are digits, the fourth is the multiplier, and the fifth is tolerance. Temperature coefficient bands can appear on precision resistors, but they’re not the primary purpose of the standard color code chart.

Thus, the chart’s main purpose is to identify the resistance value and its tolerance. The other options describe different color-coding schemes or measurements that aren’t determined by the resistor color code chart.