Why don't we call ferrite bead and choke as just an inductor?

Question

Ferrite bead and choke have inductance which means they have high reactance for higher frequencies and dissipate their power as heat. Why do we use different term like ferrite bead and choke and now just call them as inductor? Is it that only certain shaped inductor with certain core can be used as bead or choke?

Answer 1

Why don't we call ferrite bead and choke as just an inductor?

Plain inductors are usually designed to minimize dissipation. Chokes, such as ferrite beads, on the other hand, are generally designed to dissipate energy at frequencies other than DC. The different terms -- inductor vs choke -- are used to differentiate these different types of inductive components.

Answer 2

Actualy we do call them inductors, as they both are inductors - assuming that with a ferrite bead, you mean a ferrite bead inductor, instead of not just really the bead, i.e. the ring made of ferrite material, which by itself is not an inductor.

They are just called with a specific name because of their function, purpose, or material.

A choke is an inductor. Or rather, an inductor that has a main purpose of restricting or "choking" current is called a choke for that reason. So not all inductors are chokes, but all chokes are inductors.

Ferrite bead on the other hand is more difficult. You likely mean SMD ferrite core chip inductors. Originally the ferrite bead was just a ring of ceramic material through which you could put throuh a conductor, just once or multiple wounds. In some cases, where you needed the effect of a ferrite bead, you could just stick a diode or resistor terminal through the bead to have extra dampening. Of course beads with terminals so just a wire through them exist.

So again, a ferrite bead is just an inductor with ferrite core, but it operates slightly differently and it is more lossy so it also acts like a resitor so energy is dissipated as heat.

Answer 3

Components sold as "inductors" have specified saturation current, Q factor and usually self-resonant frequency. Inductance, impedance or Q vs. frequency is sometimes plotted in the datasheet, sometimes L vs. DC bias as well.

Components sold as "ferrite beads" have neither, at least as standard parameters. Impedance vs. frequency is commonly plotted in the datasheet, and impedance vs. DC bias is less commonly plotted.

Both have a DC current rating which is thermal only, and not related to electronic response.