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.
Eliminating radio interference from Apple charger
101–110 of 179 posts
Re: Eliminating radio interference from Apple charger
#102Earlier quoted context omitted.
> Since on a narrow-body aircraft passengers can easily be within 2 meters of some of the VHF antennae. But, separated by a very large piece of conductive metal. (I think even carbon fiber planes have a conductive layer in there, to prevent damage from lightning strikes.)
Isn’t carbon fiber conductive itself?
Carbon fibre is definitely conductive. A couple of years ago I measured a 1” diameter tube and got about 15ohms/ft.
Re: Eliminating radio interference from Apple charger
#103Pretty 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..
How are you going to get that 20Ah battery into an iphone?
Re: Eliminating radio interference from Apple charger
#104> 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 po…
>If RF got outside the charger and into the USB cable, it's very badly designed
Wouldn't this then be a problem with whatever car charger he is using and not with the apple device plugged into that charger?
Re: Eliminating radio interference from Apple charger
#105> 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 po…
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.
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Re: Eliminating radio interference from Apple charger
#106That'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.
MagSafe® is a registered trademark of Apple Inc., so if they call it a MagSafe® charger, it's a MagSafe® charger.
Re: Eliminating radio interference from Apple charger
#107I 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?
Can you ELI5 how does this negatively affect the consumer and why should the consumer prefer the 'bad looking' choke option?
Ferrite chokes are large and heavy. They're also not free. So the product costs more, weighs more and gets bigger.
Re: Eliminating radio interference from Apple charger
#108That'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.
Are you saying that it’s a counterfeit? Apple sells this as a MagSafe charger: https://www.apple.com/shop/product/MHXH3AM/A/magsafe-charger
Re: Eliminating radio interference from Apple charger
#109I wonder if someone suggested this at apple and was overruled because a bulky ferrite would "look bad"
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."
I'm not so sure. I can't think os a solution other than a choke off the top of my head.
Re: Eliminating radio interference from Apple charger
#110Earlier quoted context omitted.
You don't have to let the spikes from the switcher get very far. Here's the schematic for a switcher I designed.[1] This is a strange application - USB power in, 120V out, to drive an antique Teletype machine. Without any filtering, there would be huge spikes in the DC across C1-C2. But it didn't take much filtering to fix that. There's a small ferrite bead at L2, and an RC filter at the snubber at R1-C7. The back to…
Oooh. I clicked through your PCB there. I would highly recommend you read a couple books on circuit design. You have a 2 layer PCB with no ground plane and you aren't routing ground, signals passing parallel with each other on adjacent layers, you have mixed analog and digital domain, massively long traces where they could be shortened with a small jumpers. Worst offender is you aren't using a ground plane or routing…
Nothing there is going faster than about 300KHz, so the signal paths are not a big issue. If things had to go faster, there would be a proper ground plane. The tiny area around the switching IC did require careful layout (it just follows the Linear Technology data sheet) but the rest doesn't matter much.
There is no one ground. The 120VDC side has an HV ground, and the 5VDC side has a ground. The important point is to have separation between the two.