Question
Explain the colour code system for resistors with an example.
✓
Answer
$i$. In colour code system, resistors has $4$ bands on it.
$ii$. In the four band resistor, the colour code of the first two bands indicate two numbers and third band often called decimal multiplier.
$iii$. The fourth band separated by a space from the three value bands, indicates tolerance of the resistor.
$iv$. Following table represents the colour code of carbon resistor.
$v$. Example:
Let the colours of the rings of a resistor starting from one end be brown, red and orange and gold at the other end. To determine resistance of resistor we have, $x=1, y=2, z=3 \ ($From colour code table$)$
$\therefore \text { Resistance }= xy \times 10^{ z } \Omega \pm \text { tolerance }$
$=12 \times 10^3 \Omega \pm 5 \%$
$=12 k \Omega \pm 5 \%$
$[$Note: To remember the colours in order learn the Mnemonics: $\text{B.B. ROY }$ of Great Britain had Very Good Wife$]$
$ii$. In the four band resistor, the colour code of the first two bands indicate two numbers and third band often called decimal multiplier.
$iii$. The fourth band separated by a space from the three value bands, indicates tolerance of the resistor.
$iv$. Following table represents the colour code of carbon resistor.
| Colours | $1^{ st }$ digit $(X)$ | $2^{ st }$ digit $(Y)$ | Multiplier $\left(\times 10^2\right)$ | Tolerance $(%)$ |
| Black | $0$ | $0$ | $\times 10^0$ | |
| Brown | $1$ | $1$ | $\times 10^1$ | $\pm 1 \%$ |
| Red | $2$ | $2$ | $\times 10^2$ | $\pm 2 \%$ |
| Orange | $3$ | $3$ | $\times 10^3$ | |
| Yellow | $4$ | $4$ | $\times 10^4$ | |
| Green | $5$ | $5$ | $\times 10^5$ | |
| Blue | $6$ | $6$ | $\times 10^6$ | |
| Violet | $7$ | $7$ | $\times 10^7$ | |
| Grey | $8$ | $8$ | $\times 10^8$ | |
| White | $9$ | $9$ | $\times 10^9$ | |
| For Gold | $\times 10^-1$ | $\pm 5 \%$ | ||
| For Silver | $\times 10^-2$ | $\pm 10 \%$ | ||
| No colour | $\pm 20 \%$ |
Let the colours of the rings of a resistor starting from one end be brown, red and orange and gold at the other end. To determine resistance of resistor we have, $x=1, y=2, z=3 \ ($From colour code table$)$
$\therefore \text { Resistance }= xy \times 10^{ z } \Omega \pm \text { tolerance }$
$=12 \times 10^3 \Omega \pm 5 \%$
$=12 k \Omega \pm 5 \%$
$[$Note: To remember the colours in order learn the Mnemonics: $\text{B.B. ROY }$ of Great Britain had Very Good Wife$]$
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