Decode resistor color bands.

A 4-band resistor uses two significant digits, a multiplier, and a tolerance. A 5-band resistor adds a third significant digit for more precision. A 6-band resistor adds a temperature coefficient.

For brown-black-red-gold, brown is 1, black is 0, and red multiplies 10 by 100. The result is 1,000 ohms, or 1 k ohm, with a gold tolerance of +/- 5%.

Tolerance describes the allowed difference between the marked value and the actual manufactured value. A meter reading within that range can be normal.

The color code does not tell you everything needed for a design. Resistors also have power, voltage, construction, and environmental ratings.

Disconnect power and discharge stored energy before measuring resistance. An in-circuit reading can be changed by parallel components, so component identification and circuit context still matter.

Safety note: This tool is for component identification and low-voltage learning. Verify critical parts against documentation and never work on energized mains equipment.