Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.


View this topic in a long page with up to 500 replies per page Create new topic
1 | 2 
8716 posts

Uber Geek


  # 1644513 3-Oct-2016 09:12
Send private message

He is too. Circuit diagrams for a genuine charger do show the single Y-cap bridge between the high voltage DC and USB "earth" pin 4.  I'm amazed that's allowed in a class II appliance, they'd more normally be used in an earthed class I appliance with a common ground, "safety" of the cap important in case the earth connection is lost/faulty and the cap short circuits - so there are two points of failure before the user gets a zap.  That design does reduce it to one failure point - possibly not for the device itself - but when something which isn't insulated is plugged in. 

 

 


610 posts

Ultimate Geek


  # 1644536 3-Oct-2016 09:58
Send private message

Only charger I've ever had that caused this symptom was a fake Apple charger.

 

Anyway, genuine or not - who cares? It's misbehaving. Chuck it out.


 
 
 
 


8716 posts

Uber Geek


  # 1644558 3-Oct-2016 10:13
Send private message

No don't chuck it out just yet if you've got the time - stop using it - but pull it apart and post some photos.  Should be able to get a pretty good idea if it is "genuine" or not.




132 posts

Master Geek


  # 1644938 3-Oct-2016 21:15
Send private message

I measured between the case of the phone while charging and the earth and neutral pins.

 

Apple charger I have been using which produces tingling feeling 80 VAC

 

Spare unused apple charger 65 VAC also produces tingling feeling

 

Different outlet = same result

 

 

 

Phone plugged into pc via usb = no tingling feeling.

 

 

 

I have an interest of know why it is not working rather than it is not working = throw it


1906 posts

Uber Geek


  # 1645060 4-Oct-2016 09:39
Send private message

Theres a bunch of reasons why it could have failed but one likely reason has already been discussed.

Also, you've asked how to measure the voltage yet you've gone and done it anyway. If your sockets or switchboard are wired incorrectly you could have smoked something or worse.

8716 posts

Uber Geek


  # 1645230 4-Oct-2016 13:30
Send private message

Well - after participating in this thread, which motivated me to go and do some research on google university, I've come to the conclusion that either nobody knows anything or there's something wildly mysterious going on.

 

Plenty of reports of "tingling" out there.

 

No doubt that those fake chargers on the youtube link are potentially dangerous / don't meet standards.

 

I saw some fake Iphone chargers which looked so close to the genuine thing, that you'd really struggle to see any difference externally.

 

I read a blog by an electrical engineering tutor who stated that he used genuine i-phone wall warts in class to demonstrate voltage leakage, claiming that the 60-80v as measured by the OP was quite normal.  I don't know how sure he is that the chargers are genuine, I have doubts.

 

I watched a youtube where someone tested some fake wall warts vs genuine, but the scale on his meter was set at 100mA or something, one of the fakes measured at a couple of mA but he couldn't get a reading from the genuine charger.  I guess (and only a guess) that you might be able to feel that amount of leakage current as a tingle if voltage was also up there, but it's still only a fraction of the 30 mA which triggers a typical RCD.

 

I tested the two non-apple but genuine other brand USB wall warts I had here, and couldn't measure any leakage at all with my cheap digital multimeter. I don't know if either have noise suppression y-cap like the apple chargers, I'd expect some measurable leakage from them if they did, so I guess that they don't.

 

I tested a MBP charger (genuine) here, voltage leakage was about 0.25v, current 120 uA (IOW close to nothing). That charger isn't marked class II and has an earth lead.  There's no continuity between mains power earth and ground on the macbook, I assume the case is anodised, I needed to put the multimeter on a screw on the case to get a reading.

 

I tested a Sony Vaio laptop charger, voltage leak was 0.1V, current about 10 uA - so small it might have been nothing (galvanic perhaps - and nothing to do with the charger at all).  That charger is a class II (2 pin).

 

Because the current is so low the voltage readings I did get would depend on the impedance of the digital multimeter I used, but I don't know what it is, and I'm not feeling inclined to look it up.

 

I was wrong about use of Y-caps on class II devices with the circuitry used by apple, I found data confirming that it's okay if the caps are certified.  Would people making fake chargers use certified caps?  Even if they looked right, my guess is they'd be fakes.

 

I found comments from US users claiming to have genuine chargers, stating that if they reversed the polarity of how they plugged in the chargers then the "tingling" would stop.  I don't think that should make one iota of difference if it was a genuine charger with bridge rectifier as per the circuit diagram for the charger I saw,  but it would definitely make a difference with the circuit diagram for the "clone" charger shown in the youtube video linked to above in this thread, as it just used a single diode with the other mains line going directly to the transformer primary, then the (wrong type of) noise suppression cap connected from that end of the winding in the primary to the secondary.

 

TLDR - I suspect that many people who think they have "genuine" chargers don't, and it would be nice if someone with a certifiably genuine charger would measure leakage voltage and current.


22519 posts

Uber Geek

Trusted
Subscriber

  # 1645232 4-Oct-2016 13:56
Send private message

Post about an aussie seller of unapproved chargers getting some pretty significant fines.

 

https://web.facebook.com/SupremeCourtNSW/posts/705174239631801

 

Perhaps that might stop the flood of them being sold here too?





Richard rich.ms

 
 
 
 




132 posts

Master Geek


  # 1645322 4-Oct-2016 17:10
Send private message

MadEngineer: Theres a bunch of reasons why it could have failed but one likely reason has already been discussed.

Also, you've asked how to measure the voltage yet you've gone and done it anyway. If your sockets or switchboard are wired incorrectly you could have smoked something or worse.

 

I asked how as I was unsure the way I thought it should be done was 150% the correct way. I did not get an answer here so I looked it up online. Then when I was sure it was the correct method I tested it. I never 'play' with wall voltage. 

 

Cheers Fred99 for the info


22519 posts

Uber Geek

Trusted
Subscriber

  # 1645336 4-Oct-2016 17:24
Send private message

Tried my genuine samsung QC2.0 charger from my note 4, 28v to ground one way around in the socket, 36v the other way around.

 

No current at all, even on the uA scale on my fluke 15+.





Richard rich.ms

3885 posts

Uber Geek

Subscriber

  # 1645525 4-Oct-2016 23:50

Another possibility - Another appliance in the house causing lots of harmonic distortion on the mains. I have managed to get tingles from devices with switchmode supplies, when plugged into my inverter which outputs a modified square wave. Plug the same device into the national grid - no tingle.

 

Those Y caps are intended to behave as a short circuit at RF frequencies. Yet be open circuit at 50Hz. But if there is a whole ton of RF superimposed on top of the mains. Then some of it will flow straight through that Y capacitor.

 

Here is an article about Y capacitor problems (and switch mode supplies in general) http://sound.whsites.net/articles/external-psu.htm#kil






1770 posts

Uber Geek

Trusted

  # 1646427 6-Oct-2016 10:33
Send private message

Aredwood:

 

 

 

Here is an article about Y capacitor problems (and switch mode supplies in general) http://sound.whsites.net/articles/external-psu.htm#kil

 

 

That is quite an interesting article.

 

I'll be keeping my transformer-based DC wall-warts for a lot longer than I thought ...

 

I'd always kept a couple aside for for the very odd-times I needed to do some low-level audio electronics, but now I'll think about keeping (hoard)  a few more iron-cored devices.





My thoughts are no longer my own and is probably representative of our media-controlled government


1 | 2 
View this topic in a long page with up to 500 replies per page Create new topic



Twitter and LinkedIn »



Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





News »

Microsoft New Zealand Partner Awards results
Posted 18-Oct-2019 10:18


Logitech introduces new Made for Google keyboard and mouse devices
Posted 16-Oct-2019 13:36


MATTR launches to accelerate decentralised identity
Posted 16-Oct-2019 10:28


Vodafone X-Squad powers up for customers
Posted 16-Oct-2019 08:15


D Link ANZ launches EXO Smart Mesh Wi Fi Routers with McAfee protection
Posted 15-Oct-2019 11:31


Major Japanese retailer partners with smart New Zealand technology IMAGR
Posted 14-Oct-2019 10:29


Ola pioneers one-time passcode feature to fight rideshare fraud
Posted 14-Oct-2019 10:24


Spark Sport new home of NZC matches from 2020
Posted 10-Oct-2019 09:59


Meet Nola, Noel Leeming's new digital employee
Posted 4-Oct-2019 08:07


Registrations for Sprout Accelerator open for 2020 season
Posted 4-Oct-2019 08:02


Teletrac Navman welcomes AI tech leader Jens Meggers as new President
Posted 4-Oct-2019 07:41


Vodafone makes voice of 4G (VoLTE) official
Posted 4-Oct-2019 07:36


2degrees Reaches Milestone of 100,000 Broadband Customers
Posted 1-Oct-2019 09:17


Nokia 1 Plus available in New Zealand from 2nd October
Posted 30-Sep-2019 17:46


Ola integrates Apple Pay as payment method in New Zealand
Posted 25-Sep-2019 09:51



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.


Support Geekzone »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.