Which color band on a resistor indicates tolerance?

The fourth band on a resistor is used to indicate tolerance, which reflects how much the actual resistance value can vary from the specified resistance. Tolerance is essential for understanding the reliability and precision of the resistor's performance in a circuit. For example, if a resistor has a nominal value of 100 ohms and a tolerance of ±5%, the actual resistance can range between 95 ohms and 105 ohms. This band is typically gold or silver, where gold indicates a tolerance of ±5% and silver indicates ±10%. Understanding tolerance is crucial for electricians and engineers when designing circuits that require specific performance characteristics.