What are the common Flat Hollow Inductors

Flat Hollow Inductor, a single-layer coil is wound around a paper tube or bakelite skeleton with insulated wires. Such as transistor radio medium wave antenna coil.

Ferrite cores and iron powder core coils, Flat Hollow Inductor's inductance depends on the presence or absence of a magnetic core. Inserting a ferrite core into an air-core coil can increase the inductance and improve the quality factor of the coil.
Flat Hollow Inductor
Copper-core coils, copper-core coils are widely used in the ultra-short wave range. The position of the copper core in the coil is used to change the inductance. This adjustment is relatively convenient and durable.

The color-coded inductor is a kind of high-frequency Flat Hollow Inductor, which is made by winding some enameled wire on the magnetic core and then encapsulating it with epoxy resin or plastic. Its operating frequency is 10KHz to 200MHz, and the inductance is generally between 0.1uH and 3300uH. Color-coded inductors are inductors with a fixed amount of inductance. The method of marking the inductance is marked with a color ring in the same way as a resistor. Its unit is uH.

Choke coils (chokes), coils that restrict the passage of alternating current are called choke coils, and are divided into high-frequency choke coils and low-frequency choke coils.

In order to obtain a larger inductance value, air core inductors are often wound with more enameled wire, and in order to reduce the influence of the line resistance of the inductor itself on the DC current, a thicker enameled wire must be used. However, in some smaller products, it is not practical to use a very heavy air core inductor, which not only increases the cost, but also limits the size of the product.