27 ms·

Eliminating radio interference from Apple charger

283 points by oherrala 3y ago

NegativeLatency 3y ago
I wonder if someone suggested this at apple and was overruled because a bulky ferrite would "look bad"
- teaearlgraycold 3y ago
  Form over function.
  - Clamchop 3y ago
    That doesn't read as correct in this case, as a bulky and heavy "bead" on the cable makes the product less functional for the purposes of most customers. The author has different priorities but they're idiosyncratic.
- dangus 3y ago
  Honestly, I’d rather my electronics cause some noise on a frequency I never use than have a ferrite bead on every USB cable under the sun. Seems like the author resolved the problem at minimal cost and effort.
  - oherrala 3y ago
    You can be using a device and it might not harm you personally, but it could harm anyone around you using these frequencies. This includes airplanes and ground control, and boats. Your device's interference could cause problems or even life threatening dangerous situations. That's why it's illegal in many countries to cause too much radio interference (there's always some).
    - stetrain 3y ago
      There's a big difference between causing interference in a receiver a few inches away versus an airplane 1000ft above you. It may be that this charger passes the legal requirements while still causing small amounts of interference when placed near a receiver.
      - pnpnp 3y ago
        There’s also a big difference between one charger emitting some noise, and a couple million in a big city raising the noise floor for the frequency.
        Clamchop 3y ago
        It's not Apple's job to determine if there's a problem with that and regulations on this issue are, so far as I'm aware, treated very seriously.
        pnpnp 3y ago
        Sorry - I can clarify a little. If it complies with regulations, Apple is definitely not at fault. I was just replying to the above comment which could read “a little noise from a single device isn’t a big deal.” It is definitely up to regulators to decide what is acceptable, and up to Apple to meet those regulations. It’s still a little unclear from the OP whether or not the spurious emissions meet transmission requirements, but it definitely a good place to do further lab tests for compliance.
        Clamchop 3y ago
        Maybe! Seems a little unlikely that Apple could fly something like that under the radar, not for very long, but mistakes happen. Do bodies like the FCC independently verify compliance?
        TylerE 3y ago
        We're talking "little" as in "need a powerful microscope to see it", not "small".
    - Aurornis 3y ago
      > but it could harm anyone around you using these frequencies. Not really. Part of the FCC certification process is that devices need to accept interference from other devices operating within the limits. Go read the FCC sticker on the bottom of any nearby device if you don’t believe me. It’s spelled out in the text. The only reason the author had a problem is they put it right next to, quite literally, a highly sensitive receiver tuned to the exact frequency. It doesn’t mean the device was exceeding FCC limits, it means the ham operator needed to carefully set up their environment more tightly then even the FCC limits.
      - tzs 3y ago
        > Part of the FCC certification process is that devices need to accept interference from other devices operating within the limits Note that only some classes of device have this requirement to accept all interference from devices operating within the limits. For some classes of devices if a consumer device interferes with then the consumer device's owner is responsible for stopping the interference even if the consumer device is operating entirely within limits. The FCC regulations are divided into several parts, covering different devices and services. For example Part 87 covers various aviation radio services and devices, Part 97 covers Amateur Radio, and Part 20 covers mobile phones. For any given frequency there might be devices or services covered under several different parts that can radiate on that frequency. There will generally be some kind of hierarchy among them where devices are not allowed to interfere with devices higher in the hierarchy and must accept interference from devices higher in the hierarchy. The Part that covers much of consumer electronics other than mobile phones is Part 15. For most common consumer devices, if it is not a mobile phone and you did not need to get a license from the FCC to use it it probably falls under Part 15. This includes "intentional radiators", which are devices that are intended to emit radio such as WiFi routers, "unintentional radiators", which are devices that intentionally generate radio frequency energy within the device but it is meant to stay within wires or within the device, and "incidental radiators", which are devices that aren't intended to generate radio frequency energy but do so as a side effect such as DC motors and mechanical light switches. Part 15 is at the bottom of the hierarchy. For Part 15 devices, 47 CFR 15.5(b) says: > Operation of an intentional, unintentional, or incidental radiator is subject to the conditions that no harmful interference is caused and that interference must be accepted that may be caused by the operation of an authorized radio station, by another intentional or unintentional radiator, by industrial, scientific and medical (ISM) equipment, or by an incidental radiator. Other Parts can have quite different rules. For example Part 95 Subpart C, which covers radio control such as is commonly used in RC models, says this: > (a) RCRS stations must not cause interference to: > (1) Authorized radio operations in the 72–76 MHz band, including radio remote control of industrial equipment on the same or adjacent channels; or, > (2) Broadcast television reception on TV Channels 4 or 5. > (b) RCRS operations are not afforded protection from interference caused by the operation of: > (1) Industrial, scientific or medical devices (see part 18 of this chapter) operating in the 26–28 MHz band; and, > (2) Fixed and mobile stations in other services operating on the same or adjacent channels. For Amateur ("ham") Radio, the interference rules are much more extensive, because hams are authorized to use a lot of frequency bands that overlap other services. Here's a link if anyone is curious [1]. [1] https://www.law.cornell.edu/cfr/text/47/97.303 https://www.law.cornell.edu/cfr/text/47/97.303
  - terr-dav 3y ago
    The author's minimal effort was facilitated by his access to specialized equipment and time researching the issue. And as others have mentioned, Apple could have placed a small ferrite on the power supply PCB to achieve the same effect.
    - oherrala 3y ago
      > The author's minimal effort The minimal effort included hours of studying electrical engineering and radio technology at university including all the math and physics needed. Studying for amateur radio license. And after founding this issue delving deep into radio interference literature and datasheets of various components. Then setting up a test environment to replicate the issue and do tests trying to eliminate the interference. After a success write a blog post describing the solution in short and hopefully interesting way.
  - mordae 3y ago
    It coincides with several frequencies used by air traffic control in my country. I don't think it would be noticeable, but it still rises the noise floor. It's not that hard to wave a piece of nicked coax over such gadget and I expect Apple to have a 200 MHz scope to connect the coax to and see if there are any peaks in the problematic bands that might need filtering.
- yftsui 3y ago
  Just contrary, cheap products / poor engineering team use them on devices such as low end laptop chargers, usually on the DC power cord to pass EMC compliance tests. A good designed product fix them in the electronic circuits.
  - CamperBob2 3y ago
    An underrated observation. For example, the worst USB cables in my experience aren't the ones with no ferrites, they're the ones with the ferrites.
- wkat4242 3y ago
  They don't have to be on the outside, they can be inside the PSU.
  - ComputerGuru 3y ago
    And in that case they would be smaller and cheaper.
- stefan_ 3y ago
  It passed EMC so the ferrite is not needed and omitting it is literally a million dollars decision. And no surprise, the spectrum images he posted look fine. It's not and never was about eliminating all emissions, and his problem is purely putting the thing right next to the receiver.
- sigmar 3y ago
  The "bulky ferrite" he used is an easy 'hack.' the correct way to fix this wouldn't be as expensive or as bulky, as noted in the article: "I expect Apple could solve this problem with much cheaper and hidden it somewhere cleverly."
  - JKCalhoun 3y ago
    I'm not so sure. I can't think os a solution other than a choke off the top of my head.
    - ComputerGuru 3y ago
      You see these in circuits incorporating SMPS all the time: https://www.digikey.com/en/product-highlight/f/fair-rite-products/surface-mount-ferrite-beads https://www.digikey.com/en/product-highlight/f/fair-rite-pro... Smaller, cheaper, lighter, better. Just hard to retrofit if they weren’t designed as part of the board to begin with.
- Aurornis 3y ago
  Why would Apple (or any company) put a ferrite on the cable if it wasn’t needed to pass FCC? Expecting every company to make their products ultra-quiet beyond the FCC limits so amateur radio operators can use them right next to their radios isn’t realistic. You certainly wouldn’t like paying the added costs of all of your products just to make them extra quiet for hams. The author showed how easy it was for hams to solve their own problem as needed. Putting a ferrite on every charger in the world just to appease the handful of hams who want to use their radio right next to it is unreasonable.
NtG_UK 3y ago
From a marketing standpoint, Apple managed to turn "The Notch" into a feature. Whether they could do the same with "The Lump" is asking a lot IMHO. Perhaps (as the author says), the engineers could come up with something more elegant.
- ayx 3y ago
  Hahaha, I can imagine a buttoned up exec channeling jobs brandishing "the lump" on stage at one of their events. And he is saying: This is the best "lump" we've ever made. 20% Lumpier than the previous generation, 30% lighter, with a brand new crazonium body with a ferrite core!
unsupp0rted 3y ago
The other day I used one of those ultrasonic eyeglasses cleaning machines while I had my AirPods Pro in and they went crazy with static as long as I had the machine on.
- stetrain 3y ago
  That could also be because of the noise cancelling, where the microphones are "hearing" the ultrasonic frequencies and the headphones are trying to cancel them out.
  - wkat4242 3y ago
    This is most likely exactly the problem. It's very unlikely that an ultrasonic cleaner operating at a few kHz will cause interference on Bluetooth.
    - stetrain 3y ago
      Also interference on a digital Bluetooth signal would likely not cause incorrect sound to be played, rather just a pause, stutter, or connection loss.
    - somehnguy 3y ago
      And even if it did - Bluetooth is digital. At worst the music would just stop playing, and at best it would skip - there would be no static.
hulitu 3y ago
> Eliminating Radio Interference from Apple Charger Why not notify the FCC ?
- yftsui 3y ago
  There is a big possibility the author just bought a counterfeit, AFAIK all consumer electronic devices have standard EMC compliance requirements, these spikes showed should be easily observed in the 10M chambers during testing.
  - oherrala 3y ago
    The device was ordered from Apple's website.
    - yftsui 3y ago
      The issue could be coming from the AC-DC charger used with the MagSafe charger as well, maybe retest with an Apple charger?
      - oherrala 3y ago
        The issue was confirmed with two separate MagSafe chargers and three or four separate AC/DC chargers. The lab test in the post was done using laboratory DC power supply powering a DC to USB converter. Also if the interference didn't come from the disc side of charger then the issue wouldn't be resolved with ferrite bead on that end. If the issue was on the USB connector side then the bead should be placed there.
- pc486 3y ago
  The author holds a Finnish call sign, so it would be more appropriate the Finnish authorities (Traficom). That said, it's still a bad look on Apple's design or production engineering. I would expect a higher level of quality.
- Aurornis 3y ago
  Because it probably isn’t violating the FCC limits. Looking at the chart he shows, there isn’t much power coming out. The author’s use case is relatively niche. The FCC limits aren’t designed to be so strict that devices can’t emit measurable radiation at all because that’s an impossible task. The only reason the author is hearing it is because he is literally tuning a highly sensitive radio to that frequency and putting it right next to the device.
Animats 3y ago
> This radio interference was also present on the aviation frequencies (around 124 MHz) How did this thing get FCC approval? What's it's FCC approval number? Who tested this thing? Want to look that up. If RF got outside the charger and into the USB cable, it's very badly designed. The power in the USB cable is DC. There shouldn't be any significant RF component. There should be ferrite beads and capacitors in the power supply to deal with this. When the filtering is close to the switcher, it's much easier to deal with the noise, and very small ferrite beads, available in surface mount, can usually do the job. Once it gets out on an external wire, it's hard to filter. This is an old problem for Apple. A report from 2013, from a pilot charging an Ipad in an aircraft.[1] [1] https://pointsforpilots.blogspot.com/2013/06/radio-interference-of-12v-ipad-charger.html https://pointsforpilots.blogspot.com/2013/06/radio-interfere...
- wkat4242 3y ago
  Yeah and the external wire will act like an antenna especially if it's got the right length. Very bad. Strange also because Apple usually gets their PSUs made by Delta afaik and they are as good as it gets.
  - colechristensen 3y ago
    It’s not very bad. Detectable signals is not at all equivalent to interference. Folks need to relax. People actually experienced with RF wouldn’t worry about this at all, and the FCC is perfectly capable of doing its certification job.
    - amatecha 3y ago
      Breaking squelch on a scanning radio in the general vicinity is pretty bad. It shouldn't be generating such strong RFI on VHF frequencies. I use 2m (VHF) handheld radios at my desk at home with like 5 computers around me, countless chargers (including a wireless charger just like in the article). There is never a time that my radios are stopping on RFI generated within my office.
    - galangalalgol 3y ago
chankstein38 3y ago
>But it really bothers me to buy 40€ product and I still need to fix it with component costing over 2€ Honestly doesn't surprise me. I hold the same kind of sentiment after spending $1200~ on a brand new iphone 14 pro max just to find that I had to buy the charger brick so I could plug it into a wall. Come on Apple. Eliminating QOL things doesn't just automatically equal improvement.
- wyager 3y ago
  Probably like 98% of customers already have a USB power source of some kind, so that seems like a reasonable cut corner.
  - tails4e 3y ago
    Not really, modern phones have fast charge capability that's been improving generation over generetion, so what happens is new chargers are bought to take advantage of that. The older gen chargers are E-waste either way, and apple gets to charge us for something they should have included.
    - ProfessorLayton 3y ago
      Not that I endorse cutting more corners, but I personally gave away the 30w dual USBC charger that came with my MacBook Air since I already own plenty of higher powered ones that work with other devices like my work MBP and Nintendo Switch etc. I think it'd be great if Apple offered a small discount for opting out of unnecessary items.
    - bartvk 3y ago
      I don't know the percentage of course, but I think you'll agree that at least part of the client base will simply reuse their existing charger.
    - artimaeis 3y ago
      Older gen chargers didn't just become e-waste suddenly because newer bricks that support faster charging are available. I've still got a couple of the 5W USB-A bricks sitting around that I like for slow-charging devices.
sdflhasjd 3y ago
This thread looks like a relevant one to mention an issue with the Mac Studio that causes large inrush currents when you plug it in. The power connector arcs badly enough to trip a domestic 30mA RCD, it's reproducable with several units and on different electrical circuits at both home and office.
- MilaM 3y ago
  I noticed exactly the same thing on a new Mac mini M2 base model when I conncted the power cord. Now I'm relieved that it seems to be a common problem. I don't know anything about electronics. Do you think this is some kind of defect or bad design of the power supply?
  - tuetuopay 3y ago
    Apple is very generous on input capacitors for their power supplies. It's usually a sign a good design as it's one of the first places companies skimp; and ensures that even dirty wall power or highly spiky load will not trip the PSU and keep the computer fed. However, it is widely recognized that Apple overdid it on apple silicon macs. Like, they really should have skimped a bit on that one. (we have racks full of M1s at work, and boy powering the rack on is a pain due to the inrush)
    - fsh 3y ago
      Using too large input filtering capacitors without a soft-start circuit is a sign of very poor circuit design.
    - ComputerGuru 3y ago
      What size are the capacitors?
- mschuster91 3y ago
  The arcs have nothing to do with tripping the RCD part of your breaker. The RCD part only trips on a substantial current (>30 mA, or less for specialty devices, or more for upstream RCDs) between hot and ground, it doesn't care at all about the current flowing between hot and neutral. That inrush current however, given sufficiently large buffer capacitors, can be enough to trip the overcurrent protection that most if not all RCDs also have - and that one tends to get more sensitive as they age, it's a common issue with old breakers. (Another device that could trip is an arc-fault detection device, but AFDDs are fairly new and not required by many electrical codes. Nevertheless, it's a good idea to upgrade your distribution boxes with them, if you have the budget. These things save lives.)
buildbot 3y ago
Tangent- I had a similar problem in my undergrad EE capstone class where our serial connection to our microcontroller kept being filled with random garbage. I moved my laptop at one point - and it stopped! The charging cable had been lying across the wires for the serial bus, and apple chargers talk to their laptops over a serial protocol as it turned out. We were picking up crosstalk!
threemux 3y ago
OP appears to be Finnish judging by the OH callsign - perhaps his regulator cares about all the interference to the amateur bands from cheap electronic devices. As a fellow ham I can assure you that the FCC does not care about interference from these devices if they are only causing issues for amateurs. If all the cheap switching power supplies and other devices were actually tested, almost none of them would be RF quiet (or even compliant). However the large majority of the public is not impacted by these things and so there is no real constituency to get something done.
- Aurornis 3y ago
  > As a fellow ham I can assure you that the FCC does not care about interference from these devices if they are only causing issues for amateurs. This isn’t true at all. FCC would care greatly if a company the size of Apple was selling a product that violated the emission limits. That said, I don’t think this device violates the official limits. The author’s problem is that they need something extremely quiet, beyond the acceptable limits. > If all the cheap switching power supplies and other devices were actually tested, almost none of them would be RF quiet (or even compliant). If you’re suggesting that “almost none” of the power supplies on the market are actually compliant, you are incorrect. I’ve done my fair share of compliance testing. It’s true that you can find random supplies that aren’t compliant, but it’s not true that we’re all out here fudging test results and lying our way through certification. These things actually get tested.
gorkish 3y ago
I'm quite frankly amazed that this is the first time this guy has had to put a choke on something as a radio amateur. I guess he doesn't use HF that much otherwise he'd probably have opted to buy an entire bag of ferrites. Maybe his magsafe charger really is bad, but if it's plugged into a computer or a crap charger it's also likely that it's just RFI riding the cable straight out of the computer. USB stuff is the worst offender in my shack -- the majority of USB cables are just a complete joke.
- genewitch 3y ago
  where can one buy a bag of ferrites?
  - urlgrey 3y ago
    There are several options from Amazon, try searching for "Clip-on Ferrite Ring".
    - genewitch 3y ago
      I know; i hoped for a site that sells all the types of rings, binocular, clip-on - which are great for choking VHF vertical dipoles with the bottom leg being spokes that are obviously too short for the frequency - i digress. I'm also just grown weary of amazon.
    - deleted 3y ago
      [deleted]
  - wglb 3y ago
    Check out https://proaudioeng.com/fair-rite-ferrites/ https://proaudioeng.com/fair-rite-ferrites/. Also dxengineering has them.
    - genewitch 3y ago
      Type 31: > Mix 31 excellent for 1-10 MHz common mode suppression, then about same as 43 up to 250 MHz, NOT recommended for multi-ratio impedance transformers (baluns/ununs) due to material characteristics and power handling capability – ok for ham radio 1:1 feed line choke applications. Curie temperature >130 C But in looking for concise relevant information i found https://palomar-engineers.com/ferrite-products/ferrite-cores/ferrite-mix-selection https://palomar-engineers.com/ferrite-products/ferrite-cores... which i quoted above edit: also, thank you
oldbbsnickname 3y ago
There was an audible digital clock noise (of the phone) "ground loop" when charging an iPhone 6S on the same ground potential as wireless headphones Bose QC 35 (v1) while also charging the headphones AND connected via the analog headphone jack to the phone. (The noise was very loud in the headphones while operating in a passive analog input (powered off) while charging.) Moving either charger to a different ground potential removed the issue. There was probably a missing backfeed filter diode on a ground track or decoupling capacitor somewhere in the headphones' charging circuit.
ay 3y ago
Pretty detailed and creative write-up, but my first thought was “how would it have worked with a 20000mAh battery ?” - admittedly a cludge, but could be much simpler..
- bmicraft 3y ago
  How are you going to get that 20Ah battery into an iphone?
  - ay 3y ago
    Why would one need to get it into the iPhone/iPad ? Just use a power bank. (I wonder if the PD circuitry would be making the interference in its own right, though). https://www.amazon.de/Samsung-Powerbank-Capacity-Charging-Indicator/dp/B08D6W392J/ref=mp_s_a_1_3?crid=34HHZ7VUG8FV6&keywords=samsung+powerbank&qid=1696491267&sprefix=samsung+powerbank%2Caps%2C163&sr=8-3 https://www.amazon.de/Samsung-Powerbank-Capacity-Charging-In...
exabrial 3y ago
Seems like an FCC complaint is in order
JoeAltmaier 3y ago
I heard years ago, Steve Jobs wouldn't allow a choke on a cable because they looked bad. A chronic problem as long as Apple has existed?
- Aurornis 3y ago
  No company is going to put chokes on every cable if they’re not needed to pass FCC. Why would they? Would you want extra chokes on every cable just in case a ham operator might use the product somewhere? Note that this author isn’t claiming the device breaks FCC limits, just that it emits enough that his highly sensitive radio could pick it up. It’s not reasonable to be mad at a company for shipping a product that meets the limits. This guy just wanted something lower than the official limits because he’s tuning a radio to that frequency right next to it.
- yreg 3y ago
  Can you ELI5 how does this negatively affect the consumer and why should the consumer prefer the 'bad looking' choke option?
  - topspin 3y ago
    Ferrite chokes are large and heavy. They're also not free. So the product costs more, weighs more and gets bigger.
    - yreg 3y ago
      Sounds like I'm with Steve on this one.
      - topspin 3y ago
        Yeah. Who needs a usable RF spectrum when iphone has interwebs?
  - JoeAltmaier 3y ago
    Not only does the device feed high-frequency signals into your power wiring, it can get noise from it like motors turning on or off and spiking the voltage. It's only a problem if it's a problem. If they'd done proper filtering inside the device maybe it's ok.
TheRealPomax 3y ago
That's... not a magsafe charger? That's a USB-C NFC charger. By all means show it's shit in every possible way but let's not grace them by acknowledging it has anything to do with magsafe. That's a Applified Qi charger.
- meatmanek 3y ago
  MagSafe® is a registered trademark of Apple Inc., so if they call it a MagSafe® charger, it's a MagSafe® charger. https://en.wikipedia.org/wiki/MagSafe_(wireless_charger) https://en.wikipedia.org/wiki/MagSafe_(wireless_charger)
  - TheRealPomax 3y ago
    Gonna hit back with "nope". If Kleenex gets into toilet paper and tell you that toilet paper is now kleenex, the response is "you clearly don't what what the hell you're talking about, get your head out your ass". Magsafe is a magnetic power connector that clicks into a socket, whether Apple sticks their head up their ass or not.
    - jve 3y ago
      > Magsafe is a magnetic power connector that clicks into a socket, Wikipedia on MagSafe (wireless charger) > MagSafe is a proprietary, *magnetically attached* wireless power transfer That probably means I can talk with my phone while wireless charger hangs on to the back of the phone?!
      - deleted 3y ago
        [deleted]
      - elliottkember 3y ago
        Yes, you can. I have double-sided tape under mine to keep it on my desk, otherwise you pick both up. I really like them stuck-down, I use one on my bedside table and one on my desk.
- 3y ago
kazinator 3y ago
Once upon a time, when I was working at Broadcom, I put on a nice demo for some colleagues. I had a long serial line strung across my desk from a USB-Serial dongle to an embedded board. It ran under the LCD monitor. Weird banding and noise was showing on the monitor. The demo was: "watch the artifacts on the monitor go away, as I clamp this ferrite bead around the serial cable".
stainablesteel 3y ago
so does this make charging more efficient? does it help preserve hardware in the long-run? is there a guarantee that these frequencies weren't added in for some engineered purpose?
- fsckboy 3y ago
  I have a feeling this makes charging less... not efficient, but slower charging. The end of this thing is a bunch of wire in a loop, the inductor that transfers the energy to the phone. So it was odd to me that he chose the cord as the antenna that was broadcasting the noise, when I'd think it would be the business end. These frequencies being broadcast might be overlooked harmonics, ok to filter out, but they might be a designed part of the energy transfer that the charger is attempting. It's possible that he's damped the noise and the charging, but under normal use he doesn't need the maximum charge so it's still a win. not my specialty, just speculating based on basic EE knowledge.
  - ComputerGuru 3y ago
    It’s not hard to verify before throwing shade at OP’s work. 1) article specifically mentions the actual frequencies used by wireless charging up top, 2) you can refer to Wikipedia to see the same [0]: the frequency for charging is the much lower From 87-205 KILOhertz (while the harmful frequencies being filtered out are in the hundreds of MEGAhertz). So, no, this doesn’t slow down charging. [0]: https://en.wikipedia.org/wiki/Inductive_charging https://en.wikipedia.org/wiki/Inductive_charging
bloggie 3y ago
The poster's assumption that this is caused by the Apple product could be incorrect. The emissions could be caused by the supply equipment noise propagating down the cable. The load presented by the Apple product could induce the supply equipment to emit noise at that frequency.
- tuetuopay 3y ago
  I'd be much more enclined to blame the cigarette lighter to usb adapter used in the car instead of the magsafe adapter. apple usually do their homework.
MBCook 3y ago
I see something that looks like a MagSafe puck with a black plastic piece snapped on for some reason. Are we sure it’s a real MagSafe puck? The article didn’t check that. Sadly copies of Apple stuff are so rampant, especially on Amazon, if you didn’t buy it yourself from a reputable retailer. It’s quite possible it’s a fake. The little white charger bricks were copied rampantly. With Apple’s prices the fakers stand to make a lot. Given Apple’s normal engineering quality that would be my first guess. Or Bloggie’s guess it’s the PSU that’s the issue. It’s interesting they found the problem, and that a simple ferrite bead fixed it. But I have no doubt there are fakes out there for something g like the MagSafe puck. Without ruling that out simply declaring it a “piece of crap” seems unwarranted.
ggm 3y ago
Apple have form for some very odd stray vibrations around their macbook and being on charge. It's a not-electric-but-you-think-it-is thing around soft-touching their brushed aluminium case, sometimes. The "gosh, this is hot" thing when its on charge has been an issue from time to time, as the magsafe ages out, or some component on the mac board. Apparently its caused by HF on top of the desired DC, leaking out the componentry somehow as mechanical vibration.
- stouset 3y ago
  It is electric, and it happens when you're on ungrounded AC.
  - ggm 3y ago
    The write ups I've read said it was a microvibration on the board, not leakage into you. Its origin is electric no matter what.
    - stouset 3y ago
      It’s leakage current. Again, it only happens when ungrounded.
  - jve 3y ago
    And happens also on multiple DELL laptops I used/touched.
- gzalo 3y ago
  It's just a grounding issue, just that you feel the 50/60hz and your skin detects it as a weird texture/vibration. I think the periodic electric impulses may be interpreted by your brain as a fake stick-slip phenomenon and change how the texture feels. See: https://superuser.com/questions/462244/electric-shock-mild-vibrating-sensation-on-macbook-pro-when-charging/462288#462288 https://superuser.com/questions/462244/electric-shock-mild-v...
layer8 3y ago
> The final product showing the ferrite bead with three wraps of the interference causing USB cable around it. Isn’t that just two wraps? Or two and a half at best?
- ComputerGuru 3y ago
  Good question/nice catch! It does look like two wraps to me as well, but fortunately the datasheet does seem to show the same impedance for that resonant frequency at either N=2 or N=3 wraps so I think it shouldn’t matter. (And despite OP’s disqualifier, I would trust the datasheet to more or less represent what’s going to happen.)
asdefghyk 3y ago
Did the ferrite on the power cord , reduce the charge efficiency ?
gambiting 3y ago
My problem with literally every wireless charger I ever used is awful coil whine or ticking noise, really disturbing if you have the charger next to your bed. I've tried official Apple one, Samsung one, Anker, Auckley, few other random chinese brands, and they are all so loud when charging(Samsung's is probably the worst for it, as it has a fan inside - yes it charges my S23 pretty quickly but I wouldn't use it anywhere other than a loud office environment). I don't know if this is a problem of insulation or is it just inevitable given the technology used.
- mystik21 3y ago
  Interesting...I've used my Apple MagSafe charger since its release with the iPhone 12 and I have never once noticed a whine or ticking from it. AFAIK, I do not have exceptional hearing loss from age and I am able to hear all but the highest of frequencies in the audible spectrum. Would you call it particularly high pitched?
  - gambiting 3y ago
    Yeah.....like a very high pitched whine. At low battery level it's pretty much steady, then as it gets close to 100% the charger clearly provides power in pulses as it goes on and off with longer and longer gaps.
- ComputerGuru 3y ago
  I’m very sensitive to coil whine (and have documented hyperacusis for high-pitched noises) but I’ve had no issues with the Belkin wireless fast charger; BUT if you’ve had this issue with all the different makes and models perhaps it is the coil in the phone and not the one in the charger that is faulty? There’s a coil in each.

283 points by oherrala 3y ago

NegativeLatency 3y ago

I wonder if someone suggested this at apple and was overruled because a bulky ferrite would "look bad"

teaearlgraycold 3y ago
Form over function.
- Clamchop 3y ago
  That doesn't read as correct in this case, as a bulky and heavy "bead" on the cable makes the product less functional for the purposes of most customers. The author has different priorities but they're idiosyncratic.
dangus 3y ago
Honestly, I’d rather my electronics cause some noise on a frequency I never use than have a ferrite bead on every USB cable under the sun. Seems like the author resolved the problem at minimal cost and effort.
- oherrala 3y ago
  You can be using a device and it might not harm you personally, but it could harm anyone around you using these frequencies. This includes airplanes and ground control, and boats. Your device's interference could cause problems or even life threatening dangerous situations. That's why it's illegal in many countries to cause too much radio interference (there's always some).
  - stetrain 3y ago
    There's a big difference between causing interference in a receiver a few inches away versus an airplane 1000ft above you. It may be that this charger passes the legal requirements while still causing small amounts of interference when placed near a receiver.
    - pnpnp 3y ago
      There’s also a big difference between one charger emitting some noise, and a couple million in a big city raising the noise floor for the frequency.
      - Clamchop 3y ago
        It's not Apple's job to determine if there's a problem with that and regulations on this issue are, so far as I'm aware, treated very seriously.
        pnpnp 3y ago
        Sorry - I can clarify a little. If it complies with regulations, Apple is definitely not at fault. I was just replying to the above comment which could read “a little noise from a single device isn’t a big deal.” It is definitely up to regulators to decide what is acceptable, and up to Apple to meet those regulations. It’s still a little unclear from the OP whether or not the spurious emissions meet transmission requirements, but it definitely a good place to do further lab tests for compliance.
        Clamchop 3y ago
        Maybe! Seems a little unlikely that Apple could fly something like that under the radar, not for very long, but mistakes happen. Do bodies like the FCC independently verify compliance?
        TylerE 3y ago
        We're talking "little" as in "need a powerful microscope to see it", not "small".
  - Aurornis 3y ago
    > but it could harm anyone around you using these frequencies. Not really. Part of the FCC certification process is that devices need to accept interference from other devices operating within the limits. Go read the FCC sticker on the bottom of any nearby device if you don’t believe me. It’s spelled out in the text. The only reason the author had a problem is they put it right next to, quite literally, a highly sensitive receiver tuned to the exact frequency. It doesn’t mean the device was exceeding FCC limits, it means the ham operator needed to carefully set up their environment more tightly then even the FCC limits.
    - tzs 3y ago
      > Part of the FCC certification process is that devices need to accept interference from other devices operating within the limits Note that only some classes of device have this requirement to accept all interference from devices operating within the limits. For some classes of devices if a consumer device interferes with then the consumer device's owner is responsible for stopping the interference even if the consumer device is operating entirely within limits. The FCC regulations are divided into several parts, covering different devices and services. For example Part 87 covers various aviation radio services and devices, Part 97 covers Amateur Radio, and Part 20 covers mobile phones. For any given frequency there might be devices or services covered under several different parts that can radiate on that frequency. There will generally be some kind of hierarchy among them where devices are not allowed to interfere with devices higher in the hierarchy and must accept interference from devices higher in the hierarchy. The Part that covers much of consumer electronics other than mobile phones is Part 15. For most common consumer devices, if it is not a mobile phone and you did not need to get a license from the FCC to use it it probably falls under Part 15. This includes "intentional radiators", which are devices that are intended to emit radio such as WiFi routers, "unintentional radiators", which are devices that intentionally generate radio frequency energy within the device but it is meant to stay within wires or within the device, and "incidental radiators", which are devices that aren't intended to generate radio frequency energy but do so as a side effect such as DC motors and mechanical light switches. Part 15 is at the bottom of the hierarchy. For Part 15 devices, 47 CFR 15.5(b) says: > Operation of an intentional, unintentional, or incidental radiator is subject to the conditions that no harmful interference is caused and that interference must be accepted that may be caused by the operation of an authorized radio station, by another intentional or unintentional radiator, by industrial, scientific and medical (ISM) equipment, or by an incidental radiator. Other Parts can have quite different rules. For example Part 95 Subpart C, which covers radio control such as is commonly used in RC models, says this: > (a) RCRS stations must not cause interference to: > (1) Authorized radio operations in the 72–76 MHz band, including radio remote control of industrial equipment on the same or adjacent channels; or, > (2) Broadcast television reception on TV Channels 4 or 5. > (b) RCRS operations are not afforded protection from interference caused by the operation of: > (1) Industrial, scientific or medical devices (see part 18 of this chapter) operating in the 26–28 MHz band; and, > (2) Fixed and mobile stations in other services operating on the same or adjacent channels. For Amateur ("ham") Radio, the interference rules are much more extensive, because hams are authorized to use a lot of frequency bands that overlap other services. Here's a link if anyone is curious [1]. [1] https://www.law.cornell.edu/cfr/text/47/97.303 https://www.law.cornell.edu/cfr/text/47/97.303
- terr-dav 3y ago
  The author's minimal effort was facilitated by his access to specialized equipment and time researching the issue. And as others have mentioned, Apple could have placed a small ferrite on the power supply PCB to achieve the same effect.
  - oherrala 3y ago
    > The author's minimal effort The minimal effort included hours of studying electrical engineering and radio technology at university including all the math and physics needed. Studying for amateur radio license. And after founding this issue delving deep into radio interference literature and datasheets of various components. Then setting up a test environment to replicate the issue and do tests trying to eliminate the interference. After a success write a blog post describing the solution in short and hopefully interesting way.
- mordae 3y ago
  It coincides with several frequencies used by air traffic control in my country. I don't think it would be noticeable, but it still rises the noise floor. It's not that hard to wave a piece of nicked coax over such gadget and I expect Apple to have a 200 MHz scope to connect the coax to and see if there are any peaks in the problematic bands that might need filtering.
yftsui 3y ago
Just contrary, cheap products / poor engineering team use them on devices such as low end laptop chargers, usually on the DC power cord to pass EMC compliance tests. A good designed product fix them in the electronic circuits.
- CamperBob2 3y ago
  An underrated observation. For example, the worst USB cables in my experience aren't the ones with no ferrites, they're the ones with the ferrites.
wkat4242 3y ago
They don't have to be on the outside, they can be inside the PSU.
- ComputerGuru 3y ago
  And in that case they would be smaller and cheaper.
stefan_ 3y ago
It passed EMC so the ferrite is not needed and omitting it is literally a million dollars decision. And no surprise, the spectrum images he posted look fine. It's not and never was about eliminating all emissions, and his problem is purely putting the thing right next to the receiver.
sigmar 3y ago
The "bulky ferrite" he used is an easy 'hack.' the correct way to fix this wouldn't be as expensive or as bulky, as noted in the article: "I expect Apple could solve this problem with much cheaper and hidden it somewhere cleverly."
- JKCalhoun 3y ago
  I'm not so sure. I can't think os a solution other than a choke off the top of my head.
  - ComputerGuru 3y ago
    You see these in circuits incorporating SMPS all the time: https://www.digikey.com/en/product-highlight/f/fair-rite-products/surface-mount-ferrite-beads https://www.digikey.com/en/product-highlight/f/fair-rite-pro... Smaller, cheaper, lighter, better. Just hard to retrofit if they weren’t designed as part of the board to begin with.
Aurornis 3y ago
Why would Apple (or any company) put a ferrite on the cable if it wasn’t needed to pass FCC? Expecting every company to make their products ultra-quiet beyond the FCC limits so amateur radio operators can use them right next to their radios isn’t realistic. You certainly wouldn’t like paying the added costs of all of your products just to make them extra quiet for hams. The author showed how easy it was for hams to solve their own problem as needed. Putting a ferrite on every charger in the world just to appease the handful of hams who want to use their radio right next to it is unreasonable.

NtG_UK 3y ago

From a marketing standpoint, Apple managed to turn "The Notch" into a feature. Whether they could do the same with "The Lump" is asking a lot IMHO. Perhaps (as the author says), the engineers could come up with something more elegant.

ayx 3y ago
Hahaha, I can imagine a buttoned up exec channeling jobs brandishing "the lump" on stage at one of their events. And he is saying: This is the best "lump" we've ever made. 20% Lumpier than the previous generation, 30% lighter, with a brand new crazonium body with a ferrite core!

unsupp0rted 3y ago

The other day I used one of those ultrasonic eyeglasses cleaning machines while I had my AirPods Pro in and they went crazy with static as long as I had the machine on.

stetrain 3y ago
That could also be because of the noise cancelling, where the microphones are "hearing" the ultrasonic frequencies and the headphones are trying to cancel them out.
- wkat4242 3y ago
  This is most likely exactly the problem. It's very unlikely that an ultrasonic cleaner operating at a few kHz will cause interference on Bluetooth.
  - stetrain 3y ago
    Also interference on a digital Bluetooth signal would likely not cause incorrect sound to be played, rather just a pause, stutter, or connection loss.
  - somehnguy 3y ago
    And even if it did - Bluetooth is digital. At worst the music would just stop playing, and at best it would skip - there would be no static.

hulitu 3y ago

> Eliminating Radio Interference from Apple Charger Why not notify the FCC ?

yftsui 3y ago
There is a big possibility the author just bought a counterfeit, AFAIK all consumer electronic devices have standard EMC compliance requirements, these spikes showed should be easily observed in the 10M chambers during testing.
- oherrala 3y ago
  The device was ordered from Apple's website.
  - yftsui 3y ago
    The issue could be coming from the AC-DC charger used with the MagSafe charger as well, maybe retest with an Apple charger?
    - oherrala 3y ago
      The issue was confirmed with two separate MagSafe chargers and three or four separate AC/DC chargers. The lab test in the post was done using laboratory DC power supply powering a DC to USB converter. Also if the interference didn't come from the disc side of charger then the issue wouldn't be resolved with ferrite bead on that end. If the issue was on the USB connector side then the bead should be placed there.
pc486 3y ago
The author holds a Finnish call sign, so it would be more appropriate the Finnish authorities (Traficom). That said, it's still a bad look on Apple's design or production engineering. I would expect a higher level of quality.
Aurornis 3y ago
Because it probably isn’t violating the FCC limits. Looking at the chart he shows, there isn’t much power coming out. The author’s use case is relatively niche. The FCC limits aren’t designed to be so strict that devices can’t emit measurable radiation at all because that’s an impossible task. The only reason the author is hearing it is because he is literally tuning a highly sensitive radio to that frequency and putting it right next to the device.

Animats 3y ago

> This radio interference was also present on the aviation frequencies (around 124 MHz) How did this thing get FCC approval? What's it's FCC approval number? Who tested this thing? Want to look that up. If RF got outside the charger and into the USB cable, it's very badly designed. The power in the USB cable is DC. There shouldn't be any significant RF component. There should be ferrite beads and capacitors in the power supply to deal with this. When the filtering is close to the switcher, it's much easier to deal with the noise, and very small ferrite beads, available in surface mount, can usually do the job. Once it gets out on an external wire, it's hard to filter. This is an old problem for Apple. A report from 2013, from a pilot charging an Ipad in an aircraft.[1] [1] https://pointsforpilots.blogspot.com/2013/06/radio-interference-of-12v-ipad-charger.html https://pointsforpilots.blogspot.com/2013/06/radio-interfere...

wkat4242 3y ago
Yeah and the external wire will act like an antenna especially if it's got the right length. Very bad. Strange also because Apple usually gets their PSUs made by Delta afaik and they are as good as it gets.
- colechristensen 3y ago
  It’s not very bad. Detectable signals is not at all equivalent to interference. Folks need to relax. People actually experienced with RF wouldn’t worry about this at all, and the FCC is perfectly capable of doing its certification job.
  - amatecha 3y ago
    Breaking squelch on a scanning radio in the general vicinity is pretty bad. It shouldn't be generating such strong RFI on VHF frequencies. I use 2m (VHF) handheld radios at my desk at home with like 5 computers around me, countless chargers (including a wireless charger just like in the article). There is never a time that my radios are stopping on RFI generated within my office.
  - galangalalgol 3y ago

chankstein38 3y ago

>But it really bothers me to buy 40€ product and I still need to fix it with component costing over 2€ Honestly doesn't surprise me. I hold the same kind of sentiment after spending $1200~ on a brand new iphone 14 pro max just to find that I had to buy the charger brick so I could plug it into a wall. Come on Apple. Eliminating QOL things doesn't just automatically equal improvement.

wyager 3y ago
Probably like 98% of customers already have a USB power source of some kind, so that seems like a reasonable cut corner.
- tails4e 3y ago
  Not really, modern phones have fast charge capability that's been improving generation over generetion, so what happens is new chargers are bought to take advantage of that. The older gen chargers are E-waste either way, and apple gets to charge us for something they should have included.
  - ProfessorLayton 3y ago
    Not that I endorse cutting more corners, but I personally gave away the 30w dual USBC charger that came with my MacBook Air since I already own plenty of higher powered ones that work with other devices like my work MBP and Nintendo Switch etc. I think it'd be great if Apple offered a small discount for opting out of unnecessary items.
  - bartvk 3y ago
    I don't know the percentage of course, but I think you'll agree that at least part of the client base will simply reuse their existing charger.
  - artimaeis 3y ago
    Older gen chargers didn't just become e-waste suddenly because newer bricks that support faster charging are available. I've still got a couple of the 5W USB-A bricks sitting around that I like for slow-charging devices.

sdflhasjd 3y ago

This thread looks like a relevant one to mention an issue with the Mac Studio that causes large inrush currents when you plug it in. The power connector arcs badly enough to trip a domestic 30mA RCD, it's reproducable with several units and on different electrical circuits at both home and office.

MilaM 3y ago
I noticed exactly the same thing on a new Mac mini M2 base model when I conncted the power cord. Now I'm relieved that it seems to be a common problem. I don't know anything about electronics. Do you think this is some kind of defect or bad design of the power supply?
- tuetuopay 3y ago
  Apple is very generous on input capacitors for their power supplies. It's usually a sign a good design as it's one of the first places companies skimp; and ensures that even dirty wall power or highly spiky load will not trip the PSU and keep the computer fed. However, it is widely recognized that Apple overdid it on apple silicon macs. Like, they really should have skimped a bit on that one. (we have racks full of M1s at work, and boy powering the rack on is a pain due to the inrush)
  - fsh 3y ago
    Using too large input filtering capacitors without a soft-start circuit is a sign of very poor circuit design.
  - ComputerGuru 3y ago
    What size are the capacitors?
mschuster91 3y ago
The arcs have nothing to do with tripping the RCD part of your breaker. The RCD part only trips on a substantial current (>30 mA, or less for specialty devices, or more for upstream RCDs) between hot and ground, it doesn't care at all about the current flowing between hot and neutral. That inrush current however, given sufficiently large buffer capacitors, can be enough to trip the overcurrent protection that most if not all RCDs also have - and that one tends to get more sensitive as they age, it's a common issue with old breakers. (Another device that could trip is an arc-fault detection device, but AFDDs are fairly new and not required by many electrical codes. Nevertheless, it's a good idea to upgrade your distribution boxes with them, if you have the budget. These things save lives.)

buildbot 3y ago

Tangent- I had a similar problem in my undergrad EE capstone class where our serial connection to our microcontroller kept being filled with random garbage. I moved my laptop at one point - and it stopped! The charging cable had been lying across the wires for the serial bus, and apple chargers talk to their laptops over a serial protocol as it turned out. We were picking up crosstalk!

threemux 3y ago

OP appears to be Finnish judging by the OH callsign - perhaps his regulator cares about all the interference to the amateur bands from cheap electronic devices. As a fellow ham I can assure you that the FCC does not care about interference from these devices if they are only causing issues for amateurs. If all the cheap switching power supplies and other devices were actually tested, almost none of them would be RF quiet (or even compliant). However the large majority of the public is not impacted by these things and so there is no real constituency to get something done.

Aurornis 3y ago
> As a fellow ham I can assure you that the FCC does not care about interference from these devices if they are only causing issues for amateurs. This isn’t true at all. FCC would care greatly if a company the size of Apple was selling a product that violated the emission limits. That said, I don’t think this device violates the official limits. The author’s problem is that they need something extremely quiet, beyond the acceptable limits. > If all the cheap switching power supplies and other devices were actually tested, almost none of them would be RF quiet (or even compliant). If you’re suggesting that “almost none” of the power supplies on the market are actually compliant, you are incorrect. I’ve done my fair share of compliance testing. It’s true that you can find random supplies that aren’t compliant, but it’s not true that we’re all out here fudging test results and lying our way through certification. These things actually get tested.

gorkish 3y ago

I'm quite frankly amazed that this is the first time this guy has had to put a choke on something as a radio amateur. I guess he doesn't use HF that much otherwise he'd probably have opted to buy an entire bag of ferrites. Maybe his magsafe charger really is bad, but if it's plugged into a computer or a crap charger it's also likely that it's just RFI riding the cable straight out of the computer. USB stuff is the worst offender in my shack -- the majority of USB cables are just a complete joke.

genewitch 3y ago
where can one buy a bag of ferrites?
- urlgrey 3y ago
  There are several options from Amazon, try searching for "Clip-on Ferrite Ring".
  - genewitch 3y ago
    I know; i hoped for a site that sells all the types of rings, binocular, clip-on - which are great for choking VHF vertical dipoles with the bottom leg being spokes that are obviously too short for the frequency - i digress. I'm also just grown weary of amazon.
  - deleted 3y ago
    [deleted]
- wglb 3y ago
  Check out https://proaudioeng.com/fair-rite-ferrites/ https://proaudioeng.com/fair-rite-ferrites/. Also dxengineering has them.
  - genewitch 3y ago
    Type 31: > Mix 31 excellent for 1-10 MHz common mode suppression, then about same as 43 up to 250 MHz, NOT recommended for multi-ratio impedance transformers (baluns/ununs) due to material characteristics and power handling capability – ok for ham radio 1:1 feed line choke applications. Curie temperature >130 C But in looking for concise relevant information i found https://palomar-engineers.com/ferrite-products/ferrite-cores/ferrite-mix-selection https://palomar-engineers.com/ferrite-products/ferrite-cores... which i quoted above edit: also, thank you

oldbbsnickname 3y ago

There was an audible digital clock noise (of the phone) "ground loop" when charging an iPhone 6S on the same ground potential as wireless headphones Bose QC 35 (v1) while also charging the headphones AND connected via the analog headphone jack to the phone. (The noise was very loud in the headphones while operating in a passive analog input (powered off) while charging.) Moving either charger to a different ground potential removed the issue. There was probably a missing backfeed filter diode on a ground track or decoupling capacitor somewhere in the headphones' charging circuit.

ay 3y ago

Pretty detailed and creative write-up, but my first thought was “how would it have worked with a 20000mAh battery ?” - admittedly a cludge, but could be much simpler..

bmicraft 3y ago
How are you going to get that 20Ah battery into an iphone?
- ay 3y ago
  Why would one need to get it into the iPhone/iPad ? Just use a power bank. (I wonder if the PD circuitry would be making the interference in its own right, though). https://www.amazon.de/Samsung-Powerbank-Capacity-Charging-Indicator/dp/B08D6W392J/ref=mp_s_a_1_3?crid=34HHZ7VUG8FV6&keywords=samsung+powerbank&qid=1696491267&sprefix=samsung+powerbank%2Caps%2C163&sr=8-3 https://www.amazon.de/Samsung-Powerbank-Capacity-Charging-In...

exabrial 3y ago

Seems like an FCC complaint is in order

JoeAltmaier 3y ago

I heard years ago, Steve Jobs wouldn't allow a choke on a cable because they looked bad. A chronic problem as long as Apple has existed?

Aurornis 3y ago
No company is going to put chokes on every cable if they’re not needed to pass FCC. Why would they? Would you want extra chokes on every cable just in case a ham operator might use the product somewhere? Note that this author isn’t claiming the device breaks FCC limits, just that it emits enough that his highly sensitive radio could pick it up. It’s not reasonable to be mad at a company for shipping a product that meets the limits. This guy just wanted something lower than the official limits because he’s tuning a radio to that frequency right next to it.
yreg 3y ago
Can you ELI5 how does this negatively affect the consumer and why should the consumer prefer the 'bad looking' choke option?
- topspin 3y ago
  Ferrite chokes are large and heavy. They're also not free. So the product costs more, weighs more and gets bigger.
  - yreg 3y ago
    Sounds like I'm with Steve on this one.
    - topspin 3y ago
      Yeah. Who needs a usable RF spectrum when iphone has interwebs?
- JoeAltmaier 3y ago
  Not only does the device feed high-frequency signals into your power wiring, it can get noise from it like motors turning on or off and spiking the voltage. It's only a problem if it's a problem. If they'd done proper filtering inside the device maybe it's ok.

TheRealPomax 3y ago

That's... not a magsafe charger? That's a USB-C NFC charger. By all means show it's shit in every possible way but let's not grace them by acknowledging it has anything to do with magsafe. That's a Applified Qi charger.

meatmanek 3y ago
MagSafe® is a registered trademark of Apple Inc., so if they call it a MagSafe® charger, it's a MagSafe® charger. https://en.wikipedia.org/wiki/MagSafe_(wireless_charger) https://en.wikipedia.org/wiki/MagSafe_(wireless_charger)
- TheRealPomax 3y ago
  Gonna hit back with "nope". If Kleenex gets into toilet paper and tell you that toilet paper is now kleenex, the response is "you clearly don't what what the hell you're talking about, get your head out your ass". Magsafe is a magnetic power connector that clicks into a socket, whether Apple sticks their head up their ass or not.
  - jve 3y ago
    > Magsafe is a magnetic power connector that clicks into a socket, Wikipedia on MagSafe (wireless charger) > MagSafe is a proprietary, *magnetically attached* wireless power transfer That probably means I can talk with my phone while wireless charger hangs on to the back of the phone?!
    - deleted 3y ago
      [deleted]
    - elliottkember 3y ago
      Yes, you can. I have double-sided tape under mine to keep it on my desk, otherwise you pick both up. I really like them stuck-down, I use one on my bedside table and one on my desk.
3y ago

kazinator 3y ago

Once upon a time, when I was working at Broadcom, I put on a nice demo for some colleagues. I had a long serial line strung across my desk from a USB-Serial dongle to an embedded board. It ran under the LCD monitor. Weird banding and noise was showing on the monitor. The demo was: "watch the artifacts on the monitor go away, as I clamp this ferrite bead around the serial cable".

stainablesteel 3y ago

so does this make charging more efficient? does it help preserve hardware in the long-run? is there a guarantee that these frequencies weren't added in for some engineered purpose?

fsckboy 3y ago
I have a feeling this makes charging less... not efficient, but slower charging. The end of this thing is a bunch of wire in a loop, the inductor that transfers the energy to the phone. So it was odd to me that he chose the cord as the antenna that was broadcasting the noise, when I'd think it would be the business end. These frequencies being broadcast might be overlooked harmonics, ok to filter out, but they might be a designed part of the energy transfer that the charger is attempting. It's possible that he's damped the noise and the charging, but under normal use he doesn't need the maximum charge so it's still a win. not my specialty, just speculating based on basic EE knowledge.
- ComputerGuru 3y ago
  It’s not hard to verify before throwing shade at OP’s work. 1) article specifically mentions the actual frequencies used by wireless charging up top, 2) you can refer to Wikipedia to see the same [0]: the frequency for charging is the much lower From 87-205 KILOhertz (while the harmful frequencies being filtered out are in the hundreds of MEGAhertz). So, no, this doesn’t slow down charging. [0]: https://en.wikipedia.org/wiki/Inductive_charging https://en.wikipedia.org/wiki/Inductive_charging

bloggie 3y ago

The poster's assumption that this is caused by the Apple product could be incorrect. The emissions could be caused by the supply equipment noise propagating down the cable. The load presented by the Apple product could induce the supply equipment to emit noise at that frequency.

tuetuopay 3y ago
I'd be much more enclined to blame the cigarette lighter to usb adapter used in the car instead of the magsafe adapter. apple usually do their homework.

MBCook 3y ago

I see something that looks like a MagSafe puck with a black plastic piece snapped on for some reason. Are we sure it’s a real MagSafe puck? The article didn’t check that. Sadly copies of Apple stuff are so rampant, especially on Amazon, if you didn’t buy it yourself from a reputable retailer. It’s quite possible it’s a fake. The little white charger bricks were copied rampantly. With Apple’s prices the fakers stand to make a lot. Given Apple’s normal engineering quality that would be my first guess. Or Bloggie’s guess it’s the PSU that’s the issue. It’s interesting they found the problem, and that a simple ferrite bead fixed it. But I have no doubt there are fakes out there for something g like the MagSafe puck. Without ruling that out simply declaring it a “piece of crap” seems unwarranted.

ggm 3y ago

Apple have form for some very odd stray vibrations around their macbook and being on charge. It's a not-electric-but-you-think-it-is thing around soft-touching their brushed aluminium case, sometimes. The "gosh, this is hot" thing when its on charge has been an issue from time to time, as the magsafe ages out, or some component on the mac board. Apparently its caused by HF on top of the desired DC, leaking out the componentry somehow as mechanical vibration.

stouset 3y ago
It is electric, and it happens when you're on ungrounded AC.
- ggm 3y ago
  The write ups I've read said it was a microvibration on the board, not leakage into you. Its origin is electric no matter what.
  - stouset 3y ago
    It’s leakage current. Again, it only happens when ungrounded.
- jve 3y ago
  And happens also on multiple DELL laptops I used/touched.
gzalo 3y ago
It's just a grounding issue, just that you feel the 50/60hz and your skin detects it as a weird texture/vibration. I think the periodic electric impulses may be interpreted by your brain as a fake stick-slip phenomenon and change how the texture feels. See: https://superuser.com/questions/462244/electric-shock-mild-vibrating-sensation-on-macbook-pro-when-charging/462288#462288 https://superuser.com/questions/462244/electric-shock-mild-v...

layer8 3y ago

> The final product showing the ferrite bead with three wraps of the interference causing USB cable around it. Isn’t that just two wraps? Or two and a half at best?

ComputerGuru 3y ago
Good question/nice catch! It does look like two wraps to me as well, but fortunately the datasheet does seem to show the same impedance for that resonant frequency at either N=2 or N=3 wraps so I think it shouldn’t matter. (And despite OP’s disqualifier, I would trust the datasheet to more or less represent what’s going to happen.)

asdefghyk 3y ago

Did the ferrite on the power cord , reduce the charge efficiency ?

gambiting 3y ago

My problem with literally every wireless charger I ever used is awful coil whine or ticking noise, really disturbing if you have the charger next to your bed. I've tried official Apple one, Samsung one, Anker, Auckley, few other random chinese brands, and they are all so loud when charging(Samsung's is probably the worst for it, as it has a fan inside - yes it charges my S23 pretty quickly but I wouldn't use it anywhere other than a loud office environment). I don't know if this is a problem of insulation or is it just inevitable given the technology used.

mystik21 3y ago
Interesting...I've used my Apple MagSafe charger since its release with the iPhone 12 and I have never once noticed a whine or ticking from it. AFAIK, I do not have exceptional hearing loss from age and I am able to hear all but the highest of frequencies in the audible spectrum. Would you call it particularly high pitched?
- gambiting 3y ago
  Yeah.....like a very high pitched whine. At low battery level it's pretty much steady, then as it gets close to 100% the charger clearly provides power in pulses as it goes on and off with longer and longer gaps.
ComputerGuru 3y ago
I’m very sensitive to coil whine (and have documented hyperacusis for high-pitched noises) but I’ve had no issues with the Belkin wireless fast charger; BUT if you’ve had this issue with all the different makes and models perhaps it is the coil in the phone and not the one in the charger that is faulty? There’s a coil in each.