Device on cable

[Roger Dewhurst]

Cables which connect USB ports with peripherals such as cameras
frequently have black cylindrical objects on the cables a few
centimetres away from the USB end. These may be about 10mm in diameter
and 20 mm long. Are these things ferrite beads used to eliminate stray
pulses in the cable or something else? If so what?

R

 

[Grant]

On Wed, 11 Aug 2010 11:12:05 +1200, Roger Dewhurst <dewhurst@wave.co.nz> wrote:

Cables which connect USB ports with peripherals such as cameras
frequently have black cylindrical objects on the cables a few
centimetres away from the USB end. These may be about 10mm in diameter
and 20 mm long. Are these things ferrite beads used to eliminate stray
pulses in the cable or something else? If so what?

Yup, just a ferrite bead to reduce RFI.

Grant.

 

[Sjouke Burry]

Roger Dewhurst wrote:

Cables which connect USB ports with peripherals such as cameras
frequently have black cylindrical objects on the cables a few
centimetres away from the USB end. These may be about 10mm in diameter
and 20 mm long. Are these things ferrite beads used to eliminate stray
pulses in the cable or something else? If so what?

R
Yes. Maybe. Depends.

 

[John Larkin]

On Wed, 11 Aug 2010 11:12:05 +1200, Roger Dewhurst
<dewhurst@wave.co.nz> wrote:

Cables which connect USB ports with peripherals such as cameras
frequently have black cylindrical objects on the cables a few
centimetres away from the USB end. These may be about 10mm in diameter
and 20 mm long. Are these things ferrite beads used to eliminate stray
pulses in the cable or something else? If so what?

R

EMI traps, so they can pass FCC/CE radiated interferance specs.

John

 

[BeeJ]

John Larkin laid this down on his screen :

On Wed, 11 Aug 2010 11:12:05 +1200, Roger Dewhurst
dewhurst@wave.co.nz> wrote:

Cables which connect USB ports with peripherals such as cameras
frequently have black cylindrical objects on the cables a few
centimetres away from the USB end. These may be about 10mm in diameter
and 20 mm long. Are these things ferrite beads used to eliminate stray
pulses in the cable or something else? If so what?

R

EMI traps, so they can pass FCC/CE radiated interferance specs.

John

Conducted.