Calculadora de resistores

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

Calcular

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

Guia do usuário completo

O que é um resistor?

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

Código de cores: R = (digits) × multiplier ± tolerance%

Série: R_total = R1 + R2 + R3 + …

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

Poder: P = V² / R  |  I = V / R

4 Calculation Types

Código de cores

Decodifique a resistência de códigos de cores de 4, 5 ou 6 bandas em um resistor.

Resistência em série

Calculate total resistance when resistors are connected end to end.

Resistência Paralela

Calculate total resistance when resistors are connected side by side.

Dissipação de energia

Descubra quanta energia um resistor dissipa usando tensão e resistência.

Como usar esta calculadora

  1. Escolha o que deseja calcular – código de cores, série, paralelo ou potência.
  2. Enter resistor values or select color bands.
  3. Escolha unidades, se necessário (ohms, quilohms, megaohms).
  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

• Tolerância: Marrom ±1%, Vermelho ±2%, Ouro ±5%, Prata ±10%

Quick Examples

• Marrom-Preto-Vermelho-Dourado = 10 × 100 = 1000 Ω (1 kΩ) ±5%

• Dois resistores de 100 Ω em série = 200 Ω

• Dois resistores de 100 Ω em paralelo = 50 Ω

• 12 V em 100 Ω = 1,44 W de dissipação de energia

Notas importantes

  • 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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