Calcolatrice resistenze
The detailed guide below is currently available in English.
Reading the color code
Hold the resistor so the tolerance band — usually gold or silver, set apart at one edge — sits on the right. The remaining bands read left to right: each of the first two (or three) is a digit from the standard color order, and the next band multiplies by a power of ten. Brown-black-red means 1, 0, then ×100, which is 1,000 ohms: 1 kΩ.
What the tolerance band promises
Manufactured resistors drift from their nominal value, and the tolerance band states the guaranteed window. A 1 kΩ part with a gold band can legitimately measure anywhere from 950 Ω to 1,050 Ω. Five-band precision parts tighten that window to ±1% or ±2%, which matters in measurement circuits, filters, and dividers where a few percent of error compounds.
Domande frequenti
How do I tell which end of the resistor to start from?
The tolerance band sits at the far end and is often gold or silver, colors that never appear as digit bands. If both ends look similar, start from the end where the bands are packed closer together.
What do gold and silver multiplier bands mean?
They mark resistances below ten ohms: gold divides the significant digits by ten and silver by one hundred, so yellow-violet-gold is 4.7 Ω — a value common in current-sensing and RF work.
Why do some resistors have six bands?
The sixth band gives the temperature coefficient in ppm/°C, describing how much the resistance drifts as it warms. It does not change the nominal value or the tolerance range shown here.