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Chinese girl electrocuted answering her iPhone 5 on charger.

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  • Chinese girl electrocuted answering her iPhone 5 on charger.

    Youqing "You-ching" (wife) was watching CCTV (China Central TV).
    She say they report Chinese girl electrocuted answering her iPhone 5.

    Anyone know about this?

    China's house voltage is 220 V. 50 Hz.
    Doubtful that Chinese have GFIs.

    Thank you.



    I'd take an educated guess - but I'm unqualified.
    It ain't just soot, it's paydirt.
    "I swear, wherever Gift goes, argument follows." -Youtube comment

  • #2
    Re: Chinese girl electrocuted answering her iPhone 5 on charger.

    Originally posted by Robert Gift View Post
    Youqing "You-ching" (wife) was watching CCTV (China Central TV).
    She say they report Chinese girl electrocuted answering her iPhone 5.

    Anyone know about this?

    China's house voltage is 220 V. 50 Hz.
    Doubtful that Chinese have GFIs.

    Thank you.



    http://news.yahoo.com/apple-probe-de...105228058.html

    Comment


    • #3
      Re: Chinese girl electrocuted answering her iPhone 5 on charger.

      You sure it was a real Iphone? There are numerous nasty cases of imitation products out there bearing reputable trademarks on them overseas.
      Hell, when I was in Afghanistan, our Electric Shop was warned of fake Square D breakers being sold to the US forces in the region. To verify this, I went to Snieder Electric's website and sure enough, they have a webpage just to report imitation breakers. Oh yeah, that was a warm fuzzy feeling there repairing portable power panels (aka "spider boxes) knowing there is a chance the breakers I'm replacing with just might not really trip.

      Comment


      • #4
        Re: Chinese girl electrocuted answering her iPhone 5 on charger.

        I'm guessing the problem is with the power adapter, not the phone. They no longer use adaptors that used to just burn up a winding when taking a crap. Now a days they just have cheap solid-state deviced that can potentially short out causing line voltage to be on the low voltage side.

        I do not trust UL listings from china as they are often just a fraudulent sticker put on.
        Last edited by johncameron; 07-16-2013, 01:04 PM. Reason: image

        Comment


        • #5
          Re: Chinese girl electrocuted answering her iPhone 5 on charger.

          Yep that looks like a dangerous circuit. As long as the current draw is reasonable and the Zener diode is operating the output will stay at 9V.

          If the Zener goes open circuit the output voltage will go to 220V by the look of things especially at low/no current draws since the voltage dropped across R1 will be less although the Zener will be drawing some residual current to keep it in the breakdown region.

          The traditional transformer coupled power supply with bridge rectifier and smoothing cap or a switching supply with an isolating transfer is much safer.

          Comment


          • #6
            Re: Chinese girl electrocuted answering her iPhone 5 on charger.

            Originally posted by blue_can View Post
            Yep that looks like a dangerous circuit. As long as the current draw is reasonable and the Zener diode is operating the output will stay at 9V.

            If the Zener goes open circuit the output voltage will go to 220V by the look of things especially at low/no current draws since the voltage dropped across R1 will be less although the Zener will be drawing some residual current to keep it in the breakdown region.

            The traditional transformer coupled power supply with bridge rectifier and smoothing cap or a switching supply with an isolating transfer is much safer.
            Although you bring up some interesting theories, I believe that most members of this forum will agree that the culprit was a faulty flux capacitor.

            Comment


            • #7
              Re: Chinese girl electrocuted answering her iPhone 5 on charger.

              Originally posted by blue_can View Post
              Yep that looks like a dangerous circuit. As long as the current draw is reasonable and the Zener diode is operating the output will stay at 9V.

              If the Zener goes open circuit the output voltage will go to 220V by the look of things especially at low/no current draws since the voltage dropped across R1 will be less although the Zener will be drawing some residual current to keep it in the breakdown region.

              The traditional transformer coupled power supply with bridge rectifier and smoothing cap or a switching supply with an isolating transfer is much safer.
              Good point, but the breakdown voltage of the Zener (eg. output from bridge) would be far less than 220vdc. Maybe 30 volts max? I was thinking more along the lines of the bridge overheating/shorting. I believe the bridge would have to fail first.

              Perhaps they could lower the line fuse rating a bit to make it safer also?

              Comment


              • #8
                Re: Chinese girl electrocuted answering her iPhone 5 on charger.

                Originally posted by ArizonaPlumber View Post
                Although you bring up some interesting theories, I believe that most members of this forum will agree that the culprit was a faulty flux capacitor.
                Right, its not rated at 1.5 gigawatts

                Comment


                • #9
                  Re: Flux capacitors are rated at 1.21 gigawatts. Everyone know dis.

                  Originally posted by johncameron View Post
                  Right, its not rated at 1.5 gigawatts
                  Not to make fun. So sorry that the young woman died.
                  I'd take an educated guess - but I'm unqualified.
                  It ain't just soot, it's paydirt.
                  "I swear, wherever Gift goes, argument follows." -Youtube comment

                  Comment


                  • #10
                    Re: Chinese girl electrocuted answering her iPhone 5 on charger.

                    Originally posted by johncameron View Post
                    Good point, but the breakdown voltage of the Zener (eg. output from bridge) would be far less than 220vdc. Maybe 30 volts max? I was thinking more along the lines of the bridge overheating/shorting. I believe the bridge would have to fail first.

                    Perhaps they could lower the line fuse rating a bit to make it safer also?
                    It is a odd design for sure. From what I can see the voltage at the bridge will be dependent on current draw - the more current you draw the more the voltage drop across R1 and so the voltage would be less at the bridge. But as long as the Zener is operating the output will remain at 9V. The breakdown voltage of the Zener is 9V as per the circuit diagram - remember Zeners are designed to be operated in the reverse biased region .

                    The bridge does little to contribute to voltage drop - on each half cycle each diode pair in the current path will be forward biased so the voltage drop across it will be about 0.7V so it being a short is not going to be an issue. Now if R1 or the 0.33uF cap becomes a short then it would be an issue coupled with the Zener failing.

                    I do have a copy of SPICE on my PC - I could model the circuit and give a more accurate answer

                    Comment


                    • #11
                      Re: Chinese girl electrocuted answering her iPhone 5 on charger.

                      Originally posted by blue_can View Post
                      It is a odd design for sure. From what I can see the voltage at the bridge will be dependent on current draw - the more current you draw the more the voltage drop across R1 and so the voltage would be less at the bridge. But as long as the Zener is operating the output will remain at 9V. The breakdown voltage of the Zener is 9V as per the circuit diagram - remember Zeners are designed to be operated in the reverse biased region .

                      The bridge does little to contribute to voltage drop - on each half cycle each diode pair in the current path will be forward biased so the voltage drop across it will be about 0.7V so it being a short is not going to be an issue. Now if R1 or the 0.33uF cap becomes a short then it would be an issue coupled with the Zener failing.

                      I do have a copy of SPICE on my PC - I could model the circuit and give a more accurate answer
                      Thanks, Bluecan

                      My electronic knowledge is admittedly lacking, but I believe a zener diode has a maximum voltage tolerance as well as current, just as a regular diode has a maximum piv value (voltage it can handle before breaking down). Even with little or no current draw, Regulating some 200 ought volts down to 9v seems like a daunting task for that little zener. I was expecting the output from the bridge to be much less.

                      Comment


                      • #12
                        Re: Chinese girl electrocuted answering her iPhone 5 on charger.

                        Originally posted by johncameron View Post
                        Thanks, Bluecan

                        My electronic knowledge is admittedly lacking, but I believe a zener diode has a maximum voltage tolerance as well as current, just as a regular diode has a maximum piv value (voltage it can handle before breaking down). Even with little or no current draw, Regulating some 200 ought volts down to 9v seems like a daunting task for that little zener. I was expecting the output from the bridge to be much less.
                        Yes you are correct - I think my post was not very clear. During regular operation my guess is that the current draw through the Zener will be sufficient to cause enough voltage drop across R1 so as not to exceed the Zener rating. The Zener being a semiconductor device does not obey Ohm's law so while it is operating the voltage can be never anything other than 9V.

                        If you stick 220V across a 9V Zener assuming the Zener is not rated for such a high voltage, the Zener will clamp the output to 9V until it blows up due to excess current draw at which point the output will either go to 220V if the Zener goes open or to 0V if the Zener becomes a short and blow a fuse or breaker. While the Zener is operating the output can never be anything other than the Zener's rated voltage.

                        Better power supply circuit will use a regulator or even a simple pass transistor in conjunction with a Zener to set a more accurate voltage using negative feedback.

                        Comment


                        • #13
                          Re: Chinese girl electrocuted answering her iPhone 5 on charger.

                          What you say makes sense, but I don't follow the numbers. I see the resistors limiting the current to about 2ma. If Z1 was "open" the voltage would be roughly 200v after the bridge.
                          Now say Z1 in the circuit draws about 1ma, the diodes internal voltage would get dragged down 50% to around 100v and thus making it fall within it's specs. Is that right? That would only leave 1ma left as usable power?

                          Comment


                          • #14
                            Re: Chinese girl electrocuted answering her iPhone 5 on charger.

                            Originally posted by johncameron View Post
                            What you say makes sense, but I don't follow the numbers. I see the resistors limiting the current to about 2ma. If Z1 was "open" the voltage would be roughly 200v after the bridge.
                            Now say Z1 in the circuit draws about 1ma, the diodes internal voltage would get dragged down 50% to around 100v and thus making it fall within it's specs. Is that right? That would only leave 1ma left as usable power?
                            Here is a deeper analysis of the circuit to help answer your question.

                            In parallel with R1 there is a 0.33uF cap. Its reactance at 50Hz will be about 10Kohm (1/2*pi*f*c). So in reality the impedance of the R-C network will be about 10K. If you ignore R2 at an output of 9V the current drawn will be about 20mA. So it looks like this circuit was designed for a current draw of 20mA.

                            The R1/R2/C combination looks like a crude low pass filter to attenuate any high frequency noise on the mains.

                            So from the circuit it is fair to conclude the Zener will draw about 20mA with no load. We don't have to guess about it being possibly 1mA - we can infer that it will be about 20mA since that's how the circuit is configured.

                            As a load is placed on the output less current will flow though the Zener and more will flow through the load. Eventually at some point if the Zener is robbed of too much current it will exit the breakdown region and the voltage will start to rise. However, the current draw is heavy enough at that stage the drop across the R/C combination may be sufficient to not require the Zener. Hard to say without modelling the circuit more exactly on a simulation tool such as SPICE.
                            Last edited by blue_can; 07-19-2013, 12:22 AM.

                            Comment


                            • #15
                              Re: Chinese girl electrocuted answering her iPhone 5 on charger.

                              Originally posted by blue_can View Post
                              Here is a deeper analysis of the circuit to help answer your question.

                              In parallel with R1 there is a 0.33uF cap. Its reactance at 50Hz will be about 10Kohm (1/2*pi*f*c). So in reality the impedance of the R-C network will be about 10K. If you ignore R2 at an output of 9V the current drawn will be about 20mA. So it looks like this circuit was designed for a current draw of 20mA.

                              The R1/R2/C combination looks like a crude low pass filter to attenuate any high frequency noise on the mains.

                              So from the circuit it is fair to conclude the Zener will draw about 20mA with no load. We don't have to guess about it being possibly 1mA - we can infer that it will be about 20mA since that's how the circuit is configured.

                              As a load is placed on the output less current will flow though the Zener and more will flow through the load. Eventually at some point if the Zener is robbed of too much current it will exit the breakdown region and the voltage will start to rise. However, the current draw is heavy enough at that stage the drop across the R/C combination may be sufficient to not require the Zener. Hard to say without modelling the circuit more exactly on a simulation tool such as SPICE.
                              Oh yea, I forgot to include Xc in the circuit! I get it, That would put Impedance under 10K and current around 24ma. Your last paragraph gives me a lot of clarity also.

                              Thanks blue_can

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