San Diego’s Quick Answers to Your Resistor Color Code Queries
A resistor color code is a system of colored bands painted on the body of resistors used to indicate their electrical resistance value, tolerance, and sometimes temperature coefficient. Each color corresponds to a specific number or multiplier, making it possible to decode the resistor’s specifications visually.
To read a 4-band resistor, start with the first two bands to determine the base resistance value, using the color chart (e.g., red-red for 22). The third band is the multiplier (e.g., orange for x1000). The fourth band indicates tolerance (e.g., gold for ±5%).
Most through-hole resistors use color coding, but surface-mount resistors (SMD) often use numerical codes due to their small size. High-precision or high-power resistors might also use alphanumeric codes instead of color bands.
In a 4-band resistor, a gold or silver band as the fourth band represents a tolerance of ±5% and ±10%, respectively. If gold or silver appears in the third band, it acts as a multiplier, with gold signifying x0.1 and silver x0.01.
Resistor color codes are generally accurate for identifying nominal resistor values. However, actual resistance can vary within the specified tolerance range. For precise applications, it’s always best to measure the resistor with a multimeter.