Calcolatore del resistore

Decode resistor color codes, calculate series and parallel resistance, and find power dissipation. Free, fast, and easy to use.

Calcolare

Choose a calculation type, enter your values or select color bands, and click Calculate Now to get instant results with step-by-step solutions.

Guida per l'utente completa

Cos'è un resistore?

A resistor is an electrical component that limits or controls the flow of electric current in a circuit. Resistance is measured in ohms (Ω) and is usually shown by colored bands on the resistor body. This tool helps you decode those color bands, combine resistors in series or parallel, and calculate power dissipation — all for free.

All Formulas at a Glance

Codice colore: R = (digits) × multiplier ± tolerance%

Serie: R_total = R1 + R2 + R3 + …

Parallelo: 1/R_total = 1/R1 + 1/R2 + 1/R3 + …

Energia: P = V² / R  |  I = V / R

4 Calculation Types

Codice colore

Decodifica la resistenza da codici colore a 4, 5 o 6 bande su un resistore.

Resistenza in serie

Calculate total resistance when resistors are connected end to end.

Resistenza parallela

Calculate total resistance when resistors are connected side by side.

Dissipazione di potenza

Scopri quanta potenza dissipa un resistore utilizzando tensione e resistenza.

Come utilizzare questa calcolatrice

  1. Scegli cosa vuoi calcolare: codice colore, serie, parallelo o potenza.
  2. Enter resistor values or select color bands.
  3. Scegli le unità se necessario (ohm, kilohm, megaohm).
  4. Click Calculate Now and see your answer with a step-by-step breakdown and chart.

Resistor Color Code Chart

• Black=0, Brown=1, Red=2, Orange=3, Yellow=4

• Green=5, Blue=6, Violet=7, Gray=8, White=9

• Gold multiplier = ×0.1, Silver multiplier = ×0.01

• Tolleranza: Marrone ±1%, Rosso ±2%, Oro ±5%, Argento ±10%

Quick Examples

• Marrone-Nero-Rosso-Oro = 10 × 100 = 1000 Ω (1 kΩ) ±5%

• Due resistori da 100 Ω in serie = 200 Ω

• Due resistori da 100 Ω in parallelo = 50 Ω

• 12 V su 100 Ω = dissipazione di potenza 1,44 W

Note importanti

  • All resistance values must be greater than zero.
  • Color bands are read from left to right — the tolerance band is usually gold or silver.
  • Unit conversions are done automatically — just pick your preferred unit.
  • At least two resistors are needed for series and parallel calculations.

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