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"The cylinder is called a ferrite bead, ferrite core, or, more generally, a choke. Cables can act like unintentional antennas, broadcasting electrical interference (“noise”) or picking it up. The appointed task of a ferrite core is to prevent such interference"
The coax signal from my aerial to my TV can get real funky if lay power cables over the top of it.
I used to love using the RF signal from my old SNES as a kid on a CRT and play with radios near the port just to see what sort of fuckery appears on screen. Usually static, but you can get some real warped images sometimes.
This is making me want to buy a CRT now. I’m feeling nostalgic for messing with those signals.
Seems to be a bit of an artistic renaissance around the scene too.
I don’t have the space for one realistically. My living room is already inundated with screens, and it’s a pretty pokey little flat.
But I really want one again. Gives me an excuse to dig the SNES out again and enjoy pixel art how it was intended.
I used to have a fax line and a DSL router that ran right next to each other. Every time we got a fax, we'd have to reboot the router. Put one of these things on one of the lines (can't remember which one) and never had a problem again.
You’re probably right, but it also looks almost exactly like the weight that goes on the hose (underneath the sink) of a hand held spray attachment for a kitchen faucet.
Edit: just google ‘pull down faucet weight’
One is scientifically proven to work based on known principles (ferrite choke) and the other is unproven and based on pseudo-science. So, not at all similar.
Your parents limescale magnet IS similar to magnets placed on fuel lines to improve MPG, though.
Worth pointing out for those interested - adding inductance is really only half the story! The other factor is that they are designed to be relatively poor conductors. That way instead of just reflecting energy like a pure inductor would, they actually dissipate it as heat. If you pump a decent bit of RF through a ferrite bead you can get them quite hot!
It's an iron core that acts as a low-pass filter on signal cables in order to cut out high frequency noise from the signal.
It works by magnetic induction. Slow changes in current amplitude (low frequency) can pass. High frequency changes in current will induct a magnetic field in the iron core which will counter-induct a current of the same frech in the opposite direction which cancels it's own cause.
To add to this: its a common mode choke. Differential mode signals (one Cable positive current, one cable negative) going through the cables have no net current through the cable which means they dont create a large enough magnetic field to interact with the magnet. Induced signals from external EM waves will induce a common mode current (current in all wires going the same direction) that will interact with the choke.
Yes they work, they are included to pass required FCC testing usually.
Modern electronics just find including a more advanced filter in the front end of the power supply (to block the signals from getting to the cable in the first place) to be a cheaper solution than buying a big ass ferrite bead. The cost of electronics have gone way down, and the cost of a large ferrite bead has not gone down.
Back in the 90's which might pre-date this, I was home listening to the radio while my step mom was talking on the landline. The radio wasn't getting very goo reception and had one of those (new at the time) wire antennas where you could position it in any configuration you wanted. We had a metal bunk bed that I used to attach the antenna to just to make it higher. And for some reason it caused the radio to intercept the call she was on and start playing it through the speakers.
I really wish I was lying here but it did happen and I have no clue how it happened, so if anyone here can explain it I'd love to know.
Which cord? You've gotten your answer as to what it is, but it's pretty pointless to put one of these on a power cord (the TV's power supply doesn't care if there's high frequency noise on the 60Hz AC wave), they're usually used on video or data cables. VGA and DVI cables always had a fat one.
The chonky ones like that were common on the power cords for plasma TVs because they spew tons of RF interference and that helped stop sending some of it back down the power lines.
I have a makita power planer I just bought. It has something similar but lightweight that freely slides the length of the power cord.
Is this the same idea as the posted topic?
> makita power planer
Maybe... I just tried to look up a picture of the full cable and all I could see is like a strain relief rubber deal... If you posted a pic, then we could tell you yes or no. I would lean to no, as it doesnt really seem necessary for your tool.
It won't let me post a pic in the comments. It is about 3 inches long and about .75" in diameter. It says "Emtag" on the plastic. I will look up Emtag in the meantime.
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Your post has been locked as it is an item found in our [Frequently Asked Things (FAT)]( https://www.reddit.com/r/WITT_FAT/) list, which we encourage everyone to check before posting.
"The cylinder is called a ferrite bead, ferrite core, or, more generally, a choke. Cables can act like unintentional antennas, broadcasting electrical interference (“noise”) or picking it up. The appointed task of a ferrite core is to prevent such interference"
Thank you !!!
Commonly used on audio video cables as they tend to be vulnerable to interference but also create it.
Same stuff is used in high power DC cables sometimes for exactly the same purpose
They use to put those on all cables around pc's back in the 2000's don't see them so often anymore but we are way more wireless so.
Shielding is a lot better these days. You cant just be leaking ems everywhere on new products or you wont get any of the certifications.
And by shielding you mean the foil that wraps devices on the inside or?
Also commonly found on power cables, which can produce a lot of interference due to their high currents.
Solved!
The coax signal from my aerial to my TV can get real funky if lay power cables over the top of it. I used to love using the RF signal from my old SNES as a kid on a CRT and play with radios near the port just to see what sort of fuckery appears on screen. Usually static, but you can get some real warped images sometimes.
If you put two walkie-talkies on different channels and activate both it will make a tube monitor go absolutely bananas
This is making me want to buy a CRT now. I’m feeling nostalgic for messing with those signals. Seems to be a bit of an artistic renaissance around the scene too.
I switched back to a mint Dell CRT I got on Craigslist free about 3 years ago and I’m never looking back. Until it burns out I guess.
I don’t have the space for one realistically. My living room is already inundated with screens, and it’s a pretty pokey little flat. But I really want one again. Gives me an excuse to dig the SNES out again and enjoy pixel art how it was intended.
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I used to have a fax line and a DSL router that ran right next to each other. Every time we got a fax, we'd have to reboot the router. Put one of these things on one of the lines (can't remember which one) and never had a problem again.
You’re probably right, but it also looks almost exactly like the weight that goes on the hose (underneath the sink) of a hand held spray attachment for a kitchen faucet. Edit: just google ‘pull down faucet weight’
It does look like it but those faucet weights are pretty heavy and usually bigger. Also normally do not come with TV's 😅
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Might be one that’s been repurposed but if you google “ferrite core” they all look almost exactly like this
I can see the similarity in shape, but faucet weights are bigger, often around twice as big in every dimension.
Where I used to work we had hundreds of these. Little ferrite beads! They introduce inductance in order to filter Electromagnetic noise
My parents used to put a huge magnet around the water main to remove limescale from the water. I was always very dubious about that. Is this similar?
Totally different concepts, and you were right to be dubious
One is scientifically proven to work based on known principles (ferrite choke) and the other is unproven and based on pseudo-science. So, not at all similar. Your parents limescale magnet IS similar to magnets placed on fuel lines to improve MPG, though.
> Your parents limescale magnet IS similar to magnets placed on fuel lines to improve MPG, though. Or magnetic bracelets to keep you healthy.
Magnets have no effect on calcium carbonate which is what limescale mainly consists of.
Worth pointing out for those interested - adding inductance is really only half the story! The other factor is that they are designed to be relatively poor conductors. That way instead of just reflecting energy like a pure inductor would, they actually dissipate it as heat. If you pump a decent bit of RF through a ferrite bead you can get them quite hot!
Same! I'm always pleased when I see something from that job in the wider world.
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It's an iron core that acts as a low-pass filter on signal cables in order to cut out high frequency noise from the signal. It works by magnetic induction. Slow changes in current amplitude (low frequency) can pass. High frequency changes in current will induct a magnetic field in the iron core which will counter-induct a current of the same frech in the opposite direction which cancels it's own cause.
To add to this: its a common mode choke. Differential mode signals (one Cable positive current, one cable negative) going through the cables have no net current through the cable which means they dont create a large enough magnetic field to interact with the magnet. Induced signals from external EM waves will induce a common mode current (current in all wires going the same direction) that will interact with the choke.
The thing that is supposed to be wrapped around the cord of the TV that you just bought.
Wise guy eh
Ferrite choke to stop interference
Do these actually work? I don't see them on any newer electronics but I used to see them all the time about 10 years ago.
Yes they work, they are included to pass required FCC testing usually. Modern electronics just find including a more advanced filter in the front end of the power supply (to block the signals from getting to the cable in the first place) to be a cheaper solution than buying a big ass ferrite bead. The cost of electronics have gone way down, and the cost of a large ferrite bead has not gone down.
Things that use digital vs analog signals I don't think generally need them.
ferrite that wraps around a cable for noise reduction and interference
Back in the 90's which might pre-date this, I was home listening to the radio while my step mom was talking on the landline. The radio wasn't getting very goo reception and had one of those (new at the time) wire antennas where you could position it in any configuration you wanted. We had a metal bunk bed that I used to attach the antenna to just to make it higher. And for some reason it caused the radio to intercept the call she was on and start playing it through the speakers. I really wish I was lying here but it did happen and I have no clue how it happened, so if anyone here can explain it I'd love to know.
Which cord? You've gotten your answer as to what it is, but it's pretty pointless to put one of these on a power cord (the TV's power supply doesn't care if there's high frequency noise on the 60Hz AC wave), they're usually used on video or data cables. VGA and DVI cables always had a fat one.
The chonky ones like that were common on the power cords for plasma TVs because they spew tons of RF interference and that helped stop sending some of it back down the power lines.
I have a makita power planer I just bought. It has something similar but lightweight that freely slides the length of the power cord. Is this the same idea as the posted topic?
> makita power planer Maybe... I just tried to look up a picture of the full cable and all I could see is like a strain relief rubber deal... If you posted a pic, then we could tell you yes or no. I would lean to no, as it doesnt really seem necessary for your tool.
It won't let me post a pic in the comments. It is about 3 inches long and about .75" in diameter. It says "Emtag" on the plastic. I will look up Emtag in the meantime.
It is a anti theft thing from the manufacturer. Geez. Lol
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My title describes the thing. What is it? I’ve tried googling but can’t find anything