Ferrite rings...do you use them when you assemble a case?

[CityK]

They never seem big enough to fit any of the connectors through them. Am I missing something?

 

[ddrueding]

??

I've seen them on pre-assembled VGA and DVI cables, but that's it.

What application are you thinking of?

 

[CityK]

The little O rings that are included in the bag of screws with cases. Your supposed to use them on case connector wires (power, usb, etc) near that mobo header.

 

[ddrueding]

Do you have a picture of one? I've built about 20 PCs this week, and don't know what you're talking about.

 

[Howell]

They have never been with any case or MB I've purchased.

 

[Will Rickards WT]

shhhhh they are the secret listening devices the FBI is trying to get CityK to use without knowing it.

 

[CityK]

either that or major league baseball.

 

[CityK]

Do you have a picture of one? I've built about 20 PCs this week, and don't know what you're talking about.

Don't have a pic. The last three Antec cases I worked with had them (two were 3700AMB, one Sonota) included in the box with the bag of screws, drive rails, case badge etc etc. Maybe I'm mistaking something else?

 

[P5-133XL]

Are you talking about the insulating rings that are supposed to be used between the case standoffs and the MB?

 

[ddrueding]

Do you have a picture of one? I've built about 20 PCs this week, and don't know what you're talking about.

Don't have a pic. The last three Antec cases I worked with had them (two were 3700AMB, one Sonota) included in the box with the bag of screws, drive rails, case badge etc etc. Maybe I'm mistaking something else?

I have the bags from 4 Antec Sonatas, 6 Antec Lanboy Deluxe, and 2 Antec 3U Rackmount Chassis on my bench right now. I don't know what to suggest, as I see nothing that could even be called a ring...

The Rackmount chassi did ship woth some wire ties

 

[CityK]

Are you talking about the insulating rings that are supposed to be used between the case standoffs and the MB?

I don't think so Mark. Are insulation rings commonly included with Antec's, as I don't recall ever seeing them. The standoff insulation rings that I've come across in the past were all paper-like, and I haven't seen any included in a case's screws & accessory contents for a while (mind you I'm not putting systems together very often).

What I'm talking about is a pair of black O rings. They're roughly 1cm in diameter and the diameter of the ring's hole itself is probably only near .4cm. They aren't very maliable. In all three of these cases only a pair have been included.

 

[ddrueding]

What I'm talking about is a pair of black O rings. They're roughly 1cm in diameter and the diameter of the ring's hole itself is probably only near .4cm. They aren't very maliable. In all three of these cases only a pair have been included.

Never seen them, must be one of those weird, Canadian things.

 

[CityK]

Bottom row, middle

Chieftec reference

 

[CityK]

Another example:
all the cases here come with ferrite rings

Ahem, I waiting for it Will

 

[ddrueding]

Alright, so you link a PDF doc without warning and 2 web links that don't include pictures?

If I didn't know what they were, I'd be sensing a conspiracy throery here...

 

[Handruin]

 

[CityK]

Alright, so you link a PDF doc without warning

Oops....I'm usually pretty good about that

and 2 web links that don't include pictures?

See pdf.

If I didn't know what they were, I'd be sensing a conspiracy throery here...

Yeah me and Chieftec are pretty tight


The one has a much bigger hole diameter then the ones I've seen Handy. The one in the pdf photo is almost identical

 

[ddrueding]

Thanks Handurin, though the ones I've seen are usually coated in rubber? Some form of virus protection I'd imagine....

 

[Will Rickards WT]

Ahem, I waiting for it Will

Waiting for....?

I am reminded of last night's simpsons episode where the mean judge lady sentenced bart and homer to be tethered together and when marge cut the cable by the wonders of fiber optics there were able to have a two-way communication with the judge... who just happened to be in her judge outfit at the late hour...

 

[Bozo]

I've assembled about 15 compters this year so far and none of them had the ring. All were Antec cases.

The last time I remember seeing that ring was when I assembled a computer with a BX chipset, ~1999.

Bozo :mrgrn:

 

[P5-133XL]

They look like the ferite rings to protect against EMI. I don't associate them being delivered with computer cases at all - Antec or otherwise. I can't imagine why they'd be needed unless the power cables they supply are of very poor quality and are broadcasting at unacceptable levels. Even then, power cables are low frequency devices and don't tend to broadcast much at frequencies that matter. They could be used inside the PS to keep it from broadcasting, but then you shouldn't be needing to modify the PS in any form: It should already be designed properly.

 

[Mercutio]

I've seen them from time to time inside certain cases. The front panel connectors are sometimes wrapped around a ferrite ring.

 

[P5-133XL]

I've seen them from time to time inside certain cases. The front panel connectors are sometimes wrapped around a ferrite ring.

Again, for what purpose: Front pannel wiring tends to be low frequency, low voltage, low current and thereby not producing enough RF radiation to bother with.

 

[ddrueding]

I've seen them from time to time inside certain cases. The front panel connectors are sometimes wrapped around a ferrite ring.

Again, for what purpose: Front pannel wiring tends to be low frequency, low voltage, low current and thereby not producing enough RF radiation to bother with.

FW800? USB2.0? 20,000V pass-through for your cattle-prod?

 

[CityK]

They look like the ferite rings to protect against EMI

Precisely.

I don't associate them being delivered with computer cases at all - Antec or otherwise

My polling of the electorate here would seem to indicate that you are certainly not alone. As for myself, the inclusion in these last 3 antec case contents packages was the first time I personally encountered these rings. Nevertheless, I have previously come across sporadic tales/questions about ferrite rings for case wiring leads in several user forms. Given these previous descriptions, this is why I assumed that what I had encountered were also ferrite rings.

I can't imagine why they'd be needed unless the power cables they supply are of very poor quality and are broadcasting at unacceptable levels. Even then, power cables are low frequency devices and don't tend to broadcast much at frequencies that matter. They could be used inside the PS to keep it from broadcasting, but then you shouldn't be needing to modify the PS in any form: It should already be designed properly.

From what I've read in the past, some USB case leads can be particularly susceptible to becoming broadcasting antenneas

I jotted down some notes a while back. I'll dig them up and post them later on.

The front panel connectors are sometimes wrapped around a ferrite ring.

My understanding is that wrapping the wires multiple times through the core is indeed the most effective implementation.....I just can't figure out how anyone could even get the wires through the core just once without a lot of hassle, let alone multiple times

Never seen them, must be one of those weird, Canadian things.

This might actually be not too far off the mark - Perhaps a change to the regulatory standards for electrical equipment has been implemented and brought about a new inclusion requirement for ferrite rings? Just a wild guess, but certainly plausible.

Waiting for....?

Sorry Will. I had a lapse of concentration there. By the time I posted "I'm waiting for it", I had forgotten the context of your post and had instead confused\twisted it into a jestful insignuation of unfounded paranoia. Hence, when I offered proof of the existence of ferrite rings for case wire leads, I (mistakenly) jested back that it was time for you to pony up an appology. Nothing to see here. Moving along now.

 

[time]

Any cable plugged into the outside of a case is a potential broadcast antennae. The ferrite rings are probably supposed to minimize this effect; can one of the true electronics people here clarify this?

I'm stumbling around here, but perhaps the fact that there's an internal cable to the front panel connectors creates a bigger problem than usual? After all, doesn't USB 2.0 have a bitrate of 240Mbs?

I'd guess that they only expect you to push a single loop of cable through it, i.e. double it over and push it through for about a centimeter or so.

 

[CityK]

Checking my notes I had written down about usb cables and ferrite turned out to be not particularly illuminating. I just noted that troubles with usb devices can often be tracked back to crappy cables susceptable to EM noise, and that simply buying a ferrite core and looping the cable through it can do wonders to alleviate said problems...or buying properly sheild usb cables.

Then at some other time I jotted down some other stuff (from where and when who knows):

Ferite components are frequently used on circuit leads, component leads (resistors...capacitors, etc), in the design of circuits to eleminate the generation of unwanted radiation and/or coupling of radio_frequency energy that would cause havoc to the device's proper operation.

The wire case leads, originating from the motherboard headers act as radiating antennas and generate interference. Inserting or looping the case wires through a ferrite ring will reduce the cable's ability to radiate interference (It is the same as inserting a radio_frequency choke in series with the lead). This is most effective if the loop is placed as close to the mobo header as possible, thereby choking/cutting off the RF energy before it has adequate antenna length to radiate ... as opposed to placing the ferite choke near the switches and LED's. The effectiveness can be increased even more by passing the ends of the leads through the ferite loop several times...effectively increasing the resistance [impedence] to the flow of RF energy!

 

[Computer Generated Baby]

Any cable plugged into the outside of a case is a potential broadcast antennae. The ferrite rings are probably supposed to minimize this effect; can one of the true electronics people here clarify this?

Actually, the other way around -- wires or cabling acting like a receiving aerial. If you have possible "broadcast" RFI problems, then shielding to earth is the answer.

Ferrite beads and donuts simply suppress millivolt-level signals down close to nil without producing any ill effects like DC offset, phase change, or significant attenuation on the "larger" signals traversing the wiring. Use of ferrites is a form of permeable noise filtering, in that the signal permeates the filter.

 

[time]

Sorry CGB, it's to minimize broadcast. Perhaps you're confusing digital and analog design issues?

"millivolt-level signals" are of little interest in a digital application. And no offense, but "permeable noise filtering, in that the signal permeates the filter" is gobbledegook. That's what a filter does: it passes some things and blocks others.

A common problem with most rf generating equipment (transmitters, computers, dimmers, fluorescent lights, motors) is the radiated rf from the external leads attached to them. This is called rfi (rf interference) or emi (electromagnetic interference), and it can cause interference to the reception of TV or radio broadcasts, and even interfere with audio equipment.
...
Disconnect all possible external leads from the computer and receiver, including the antenna, especially any interconnecting leads, which should be screened with grounding at the receiver end.
...
Now begin applying suppression on each lead (one at a time) and noting the effect on rfi. The mains lead may require a few turns wound through a large core such as the FT-240-43/77, but the split beads are easier to fit to terminated cables such as video, keyboard, mouse etc.

http://www.catchnet.com.au/~rjandusimports/

 

[Computer Generated Baby]

Sorry CGB, it's to minimize broadcast...

Not in the case of what we're talking about here, though! The use of ferrites here is to reduce hash on low-speed signal lines. In the case of what we are talking about here (computer chassis), a well-engineered shielding design is the answer.

Perhaps you're confusing digital and analog design issues?

No offence, but you just can't separate the analogue domain from the digital domain when it comes to the topic of noise (in addition to noise levels, some other analogue factors in a digital circuit would be input and output impedance, propagation, attenuation).

"millivolt-level signals" are of little interest in a digital application.

If you are thinking *strictly* logic levels at low frequencies, then yes, there is no affect as such an this is where digital triumphs. However, as far as common high-speed digital goes, low levels of noise can absolutely play havoc on its operation. I'll give a hint: edge clock determination.

And no offense, but "permeable noise filtering, in that the signal permeates the filter" is gobbledegook.

Well, it certainly is not gobbledygook. A *digital* signal that goes through a permeable filter is completely unadulterated.

 

[NRG = mc²]

I've had these provided with almost all cases I've used, though I never bother to fit them.

 

[e_dawg]

The last time I saw ferrite rings bundled with a PC was with my Apple IIe, circa 1983.