STS develops and manufactures customised chokes for all applications. Below the most important types are shown briefly.

Storage choke
Direct current flows through the choke, with a delta-shaped alternating current superposed. The frequency of this alternating current can amount to one times or even double the operating frequency, depending on the topology of the switched-mode power supply.

Resonance choke
In the choke there flows a pure alternating current having the same frequency as the operating frequency.

Pulse choke
If we consider the period of the operating frequency, a high pulse current flows in a short time through the choke. For the rest of the time the choke is de-energized.

PFC choke
In the choke there flows a current with one times or double the mains frequency. In addition a high-frequency alternating current is superposed on it.

Non-linear choke
The inductance curve depends to a major extent on the load applied to the choke (e.g. stepped air gap or transductor choke).

In order to achieve the required technical characteristics, a wide range of core materials, conductors and other materials are used, regardless of the manufacturer and the brand.

The core materials normally used are:

• soft ferrite
• iron powder
• carbonyl iron powder
• MPP
• Kool Mµ, MSS
• High Flux
• Si-Fe
• nickel-iron
• amorphous cores
• nanocrystalline cores