---
title: "Resistor value from colour code"
subject: "Basic Electronics Engineering"
chapter: 1
key: "semester_2/basic_electronics_engineering:resistor-color-code-value"
source: https://www.bctengineer.com/q/semester_2/basic_electronics_engineering/resistor-color-code-value
site: BCT Engineering
---

# Resistor value from colour code

Basic Electronics Engineering · Chapter 1: Basic Circuits Concepts

- Asked in: 2070 Magh, 2 marks
- Video: [Resistor Color Coding Explained](https://www.youtube.com/watch?v=pD2Ce1lujNA) — ALL ABOUT ELECTRONICS
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_2/basic_electronics_engineering/resistor-color-code-value
- Whole chapter: https://www.bctengineer.com/md/semester_2/basic_electronics_engineering/chapter-1

## Question

Find the value of resistor from following colour code. a) Red Orange Green Silver  b) Yellow Black Gold Gold

## Short answer

a) Red-Orange-Green-Silver: 2, 3, ×10⁵, ±10% → 2.3 MΩ ±10%. b) Yellow-Black-Gold-Gold: 4, 0, ×0.1, ±5% → 4 Ω ±5%.

## Answer

Colour values: Black 0, Brown 1, Red 2, Orange 3, Yellow 4, Green 5, Blue 6, Violet 7, Grey 8, White 9. Multiplier: Gold ×0.1, Silver ×0.01. Tolerance: Gold ±5%, Silver ±10%.

#### a) Red, Orange, Green, Silver
- 1st digit: Red = 2
- 2nd digit: Orange = 3
- Multiplier: Green = ×10⁵
- Tolerance: Silver = ±10%

R = 23 × 10⁵ = 2,300,000 Ω

**Answer: 2.3 MΩ ± 10%** (range 2.07 MΩ to 2.53 MΩ)

#### b) Yellow, Black, Gold, Gold
- 1st digit: Yellow = 4
- 2nd digit: Black = 0
- Multiplier: Gold = ×0.1
- Tolerance: Gold = ±5%

R = 40 × 0.1 = 4 Ω

**Answer: 4 Ω ± 5%** (range 3.8 Ω to 4.2 Ω)

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Which colour sequence represents the digits 2, 3?
   A. Red, Orange
   B. Orange, Red
   C. Red, Yellow
   D. Brown, Orange
   Answer: A. Red = 2, Orange = 3. (Key point: Colour values)

2. For Red Orange Green Silver, what is the resistance?
   A. 2.3 kΩ ± 10%
   B. 23 Ω ± 10%
   C. 2.3 MΩ ± 10%
   D. 230 kΩ ± 10%
   Answer: C. Green multiplier = ×10⁵, so 23 × 10⁵ = 2.3 MΩ. (Key point: Multiplier green)

3. For Yellow Black Gold Gold, what is the value?
   A. 400 Ω ± 5%
   B. 4 Ω ± 5%
   C. 40 kΩ ± 5%
   D. 0.4 Ω ± 5%
   Answer: B. 40 × 0.1 = 4 Ω, tolerance gold = ±5%. (Key point: Gold multiplier)

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