Inductor

An inductor is a passive electronic component that stores energy in the form of a magnetic field. In its simplest form, an inductor consists of a wire loop or coil. The inductance is directly proportional to the number of turns in the coil. Inductance also depends on the radius of the coil and on the type of material around which the coil is wound. However An inductor, also called a coil or reactor, is a passive two-terminal electrical component that stores electrical energy in a magnetic field when electric current is flowing through it.

An inductor is characterized by its inductance, which is the ratio of the voltage to the rate of change of current. In the International System of Units (SI), the unit of inductance is the henry (H).

TYPES OF INDUCTOR

Air core inductor
Radio frequency inductor
Ferromagnetic core inductor
Laminated core inductor
Ferrite-core inductor
toroidal core inductor
Variable inductor

How to identify inductor markings

Inductors can be labeled with a number of different ways. The most common are text codes and color codes.

Values are in micro Henries (μH)
First two digits are the value
Third digit is the multiplier
If there is an R, its acts as a decimal point, and there is no multiplier
Examples:

101 = 10*10¹μH = 100μH
4R7 = 4.7μH

Suffix

Sometimes the precision of the inductor will be marked, using a final letter F, G, J, K, or M

F = +/-1%

G = +/-2%

J = +/-5%

K = +/-10%

M = +/-20%

Color Code Marking

Inductors can be marked by colored bands or colored dots. Each color represents a value.

Band A	Band B	Band C	Band D
1st Digit	2nd Digit	Multiplier	Tolerance
		Silver 10^-2 (0.01uH)	Gold 5%
		Gold 10^-1 (0.1uH)	Silver 10%
	Black 0	Black 10⁰ (1uH)	Black 20%
Brown 1	Brown 1	Brown 10¹ (10uH)
Red 2	Red 2	Red 10² (100uH)
Orange 3	Orange 3	Orange 10³ (1000uH)
Yellow 4	Yellow 4	Yellow 10⁴ (10000uH)
Green 5	Green 5	Yellow 10⁴ (10000uH)
Blue 6	Blue 6
Violet 7	Violet 7
Gray 8	Gray 8
White 9	White 9