Inductors can be made from coiled cores of electrically conductive materials, typically such as copper wire, or the core can be removed or replaced with a ferromagnetic material. A core material with a higher permeability than air can bind the magnetic field more tightly around the inductive element, thus increasing the inductance. There are many different types of inductors, most of which are made with an enamel coated wire spooled around a ferrite wire, while some protective inductors have the coil completely inside the ferrite.
Some inductive components have adjustable cores. This allows the inductor size to be changed. Small inductors can be etched directly onto the PCB using a method of laying down spiral traces. Small value inductors can also be manufactured in integrated circuits using the same process used to manufacture transistors. In these applications, aluminum interconnects are often used as the conducting material.
Regardless of the method used, the most common application based on practical constraints is a circuit called a “rotator”, which uses a capacitor and active element to exhibit the same characteristics as an inductive element. Inductive elements used to isolate high frequencies are often constructed with a wire passing through a magnetic post or bead.
Small Inductors
Small fixed inductors are usually made of enameled wire wound directly on the core, mainly used in filtering, oscillation, trap, delay and other circuits, it has two forms of sealed and non-sealed package, both forms have a vertical and horizontal shape structure.
1, vertical sealed fixed inductors vertical sealed fixed inductors using isotropic pins, domestic inductance range of 0.1 ~ 2200