function of a choke 3

[alwaink]

Could someone explain what a choke does? I read from one site that it converts AC to DC and another that it filters AC frequency. I thought AC to DC was done through a rectifier. I'm a bit confused.

 

[DanDel]

'Choke' used to be a pseudonym for an inductor. While an inductor does not convert AC to DC, it does provide a higher impedance to AC, and the impedance increases with the frequency, so it is commonly used as part of a filter.

 

[CJCPE]

A choke provides inductance (L) or inductive impedance. It may also be called an inductor or a reactor. Since the impedance in ohms is 2*Pi*f*L, the impedance increases with frequency. Than makes is useful for filtering. The term "choke" seems to be more often applied to the device when it is used after a rectifier to reduce the AC ripple in the rectified DC output and also to reduce harmonic currents on the AC side.

When it is used in AC circuits, it seems to be more often called a reactor. Reactors are used on the AC side of rectifiers to reduce the harmonic current content. They are also used to reduce the available fault current.

 

[alwaink]

That makes more sense. So it's just a matter of naming the filtering device before or after the AC-DC conversion. Thanks.