What is a Color Coded Inductor Coil?

Figure 1: A color coded inductor coil in operation.

Similar to color-ring resistors, color coded inductor Solenoid coil use colors to represent different numbers, which can indicate the inductance of the inductor. Some value is directly marked on the package; some needs to be measured with a meter.
The color coded inductor coil, also called a color ring inductor coil, is a component that utilizes self-inductance. In the circuit, the inductor coil often forms a resonance circuit, a filter circuit, etc. together with a capacitor. Because the working frequency is very different, the number of turns of the inductor coil and the material of the skeleton are also very different.

The Principles of Color Coded Inductor Coil

When the color code inductor forms a closed loop, the induced electric potential will generate an induced current. Color coded inductance has properties similar to inertia in mechanics. Usually when the knife switch is opened or the knife switch is turned on, a spark will be generated, which is caused by a high induced potential caused by the self-inductance phenomenon.

Figure 2: Color coded inductors.

The change of the inductance of the color coded inductor comes from the change of the external AC power supply, so from the objective effect, the color-coded inductor has the characteristic of preventing the current change in the AC circuit.
In short, when the color coded inductor is connected to the AC power supply, the magnetic field lines inside the color-coded inductor will change constantly with the alternating current, resulting in the electromagnetic induction of the color-coded inductor. The electromotive force generated by the change of the current of the inductor itself is called the color coded induction.

How to Read the Color?

The color on the coil represents different inductance of the inductor. Here is a table showing the corresponding inductance of each color.

Figure 3: The color reading guide for color coded inductor coil.

6. Choose the Coil with a Relatively Larger Diameter

For example:
The tolerance of the inductor quantity and error is 1.0uH, and the color code of the inductance of ±10% is: brown, black, gold, silver.
The tolerance of the inductor and the error is 0.22uH, and the color code of the inductance of ±20% is: red, red, silver, black.
The reading of the color coded inductor is similar to the reading of the color coded resistor. Different colors represent different data. In general, the marking method of color coded inductors is basically the same as that of color coded resistors.

As for the reading value of the color coded inductor, the first ring and the second ring are real numbers, the penultimate ring multiplication, and the final ring the deviation number.
In other words, the penultimate ring only has six shades of silver, gold, black, brown, red, and orange. The final ring is the deviation: if the deviation of the color coded inductor is normal, the ±10% is mainly used, followed by ±5% as a small part. Therefore, the final shades are only silver and gold.

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