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)
∴ Resistance = xy × 10z Ω ± tolerance
= 12 × 103 Ω ± 5%
= 12 kΩ ± 5%
[Note: To remember the colours in order learn the Mnemonics: B.B. ROY of Great Britain had Very Good Wife]
