In a resistor, what does the third band usually represent?

In a resistor, the third band typically indicates the tolerance percentage, which is critical for understanding the accuracy of the resistor's reported resistance value. Resistors are color-coded to convey important information regarding their specifications.

The first two bands represent digits that, when combined with multipliers indicated by the second band, establish the fundamental resistance value. The third band specifically communicates how much the actual resistance can vary from that specified value, thus defining the precision of the resistor's performance in a circuit.

This tolerance value is essential for applications where exact resistance is vital, as it informs engineers and designers of how much fluctuation they can expect in the resistor's performance due to manufacturing differences. Understanding tolerance helps ensure that designs will function correctly within the specified range.

Other options do not accurately describe the third band’s purpose in a standard resistor marking system. While material and maximum voltage rating are significant factors in selecting components, they are not represented by the color bands on resistors.