---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 06/25/14: 14 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:24 AM - Re: Re: Brownout battery charging? (Tcwtech) 2. 04:18 AM - Re: Brownout battery charging? (donjohnston) 3. 04:19 AM - Re: How is it I get a shock from an iPod? (John MacCallum) 4. 04:21 AM - Re: How is it I get a shock from an iPod? (racerjerry) 5. 06:45 AM - Re: How is it I get a shock from an iPod? (Eric M. Jones) 6. 06:51 AM - Re: How to decide if a heat sink is required for a Rect Br (Eric M. Jones) 7. 07:11 AM - Vintage Electronics at ShopGoodwill.com (Eric M. Jones) 8. 07:17 AM - Re: Vintage Electronics at ShopGoodwill.com (donjohnston) 9. 07:19 AM - Re: iPod shocks (GLEN MATEJCEK) 10. 07:45 AM - Re: Re: iPod shocks (Daniel Hooper) 11. 07:47 AM - Re: Re: iPod shocks (Etienne Phillips) 12. 08:03 AM - Re: Re: iPod shocks (James Kilford) 13. 10:44 AM - Re: How is it I get a shock from an iPod? (Eric Page) 14. 07:12 PM - Re: Re: iPod shocks (Dave Saylor) ________________________________ Message 1 _____________________________________ Time: 03:24:53 AM PST US Subject: Re: AeroElectric-List: Re: Brownout battery charging? From: Tcwtech Our information is that at least the GRT 24 volt version is Not 12-24 capable and suffers from low voltage reboot issues during engine cranking and for some during electric hydraulic pump actuation. We have solved their issues on a number of occasions using the 24 volt ips product. Bob Newman. TCW technologies. > On Jun 24, 2014, at 10:42 PM, Tim Andres wrote: > > > If it's just brownout, and you have a 28V system...I'm guessing the EFIS will run on 12-28 volts, so I doubt you'll sag under 12 volts when cranking. Be fine won't it? > Tim > >> On Jun 24, 2014, at 6:34 PM, "donjohnston" wrote: >> >> >> >> nuckolls.bob(at)aeroelect wrote: >>> >>> What's your anticipated architecture? >> >> Not sure what you're looking for. Like I said, I'm running a VPX-Pro, 24v electrical system. I don't know how much more you need beyond the diagram I posted. Let me know, and I'll provide it. >> >>> Under what conditions do you anticipate a battery failure? >> >> I don't anticipate a battery failure. My primary reason is to keep the EFIS during engine start. An added benefit is being able to power the EFIS in the event of a battery or contactor failure. The latter is just an added benefit. Not a primary reason. >> >> >>> >>> Yeah, you'll have to roll your own and you're going to be loathe to install anything with robustness . . . meaning small . . . meaning not particularly long-lived when connected across a DC bus system. >> >> Well, I was looking at 3-5ah (the EFIS and AHRS draw about 2a). So I certainly wasn't looking for cross-country endurance. >> >> >>> The deslumpifier is by far the more elegant solution . . . with a Z-13/8 or similar architecture and rudimentary preventative maintenance, there's just no compelling driver for bolting more boxes full of lead to your airplane . . . even itty-bitty ones. >> >> Eric Jones provided me with a schematic for his DeSlumpifier a while back. But after thinking about the time to make the changes for a 24v system and build it, I thought that a backup battery option may be quicker and easier. >> >> >> >> >> Read this topic online here: >> >> http://forums.matronics.com/viewtopic.php?p=425412#425412 > > > > > ________________________________ Message 2 _____________________________________ Time: 04:18:51 AM PST US Subject: AeroElectric-List: Re: Brownout battery charging? From: "donjohnston" tim2542(at)sbcglobal.net wrote: > If it's just brownout, and you have a 28V system...I'm guessing the EFIS will run on 12-28 volts, so I doubt you'll sag under 12 volts when cranking. Be fine won't it? > Tim No. With GRT, you get either a 12v or a 24v version. The 24v version drops off at around 21v. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=425439#425439 ________________________________ Message 3 _____________________________________ Time: 04:19:13 AM PST US From: John MacCallum Subject: RE: AeroElectric-List: How is it I get a shock from an iPod? HI Dave, I think Carl can probably answer this best but I should think it=99s caused by the Switch mode power supply of the Charger and a floating ground coupled with Double Insulation. In layman=99s terms the charger is building up a charge because it=99s not earthed and because you are by standing on the ground (or concrete) you get a small amount of Current that flows through yourself from Ground. Therefore if your skin resistance is low enough you feel a slight tingle. This often happens with other devices that have floating grounds. Tv=99s, Stereo Systems and other such devices. It=99s gets to be more than 5 volts because the power supply has internal high frequency switching transistors that are driving an output transformer the primary winding of which is at least at 110 volts, (in the US and 240 volts here in Australia). I don=99t think it is really correct for Apple to refer to it as a static charge because usually if you continue to touch the device the tingle will persist because the source of the current is still present but others may have more information on that subject. Cheers John MacCalllum From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Dave Saylor Sent: Wednesday, 25 June 2014 3:49 PM Subject: AeroElectric-List: How is it I get a shock from an iPod? Here's a non-aviation question for the group. Unless you fly with an iPod, I guess. Background: My son complained today that he got shocked by an iPod. FWIW, it's a 5th gen nano plugged into an Apple USB charging cube by an Apple charging cord--not knock-off parts. First I said yeah, right...but he insisted so like an idiot I figured I'd show him how that was impossible....and of course I got shocked too. Not as strong as 120VAC but enough to get my attention. We were both barefoot (key, I think...) on a concrete slab, in the garage. It happened when either of us touched the metal lock switch. I've never had any issues with the power strip we were using. Putting a meter between the lock switch and ground I measure an invigorating 60VAC. Between the neutral of the power strip to any other ground is zero, so I figure the power strip is wired correctly. Inverting the cube (it's not polarized) makes no difference, still 60VAC. I tried a few things: different plug, no shock. Different cord, no shock. Different cube, no shock. I went back to the original combination: BZZZZT. So it is repeatable. There's an Apple support document describing the possibility of static shock when using their device. This was not your typical feet-on-carpet-touch-a-doorknob static shock. It was sustained as long as I touched the lock switch. The iPod works and charges just fine except for that particular combination of parts. Questions: In general, how is it that an iPod can give me an electric, non-static shock? I thought that USB was only 5V. How does more than 5V get into the system? Or more appropriately, how does it get out of the system? Could this happen from a 12V system, or is part of the 120V getting through? Thanks for tolerating a non-airplane topic, --Dave Saylor ________________________________ Message 4 _____________________________________ Time: 04:21:39 AM PST US Subject: AeroElectric-List: Re: How is it I get a shock from an iPod? From: "racerjerry" Buy one of those cheap LED type plug-in polarity testers from a home improvement store and check the polarity of your garage outlets. It sounds like you may have a dangerous condition in your shop with possible wire polarity reversal and/or a grounded neutral. For about 5 bucks, the tester will quickly alert you of any problem. Another good idea is to retrofit a ground fault circuit interrupter (GFCI) into garage outlets now required by code for new construction. A single GFCI will protect all downstream outlets, so a GFCI is not required at every outlet for protection and retrofitting is not a big deal. GFCIs are LIFESAVERS. Your shock may be a wake-up call to a larger and quite dangerous problem for the sake of your children and their breadwinner, please dont ignore it. -------- Jerry King Read this topic online here: http://forums.matronics.com/viewtopic.php?p=425442#425442 ________________________________ Message 5 _____________________________________ Time: 06:45:03 AM PST US Subject: AeroElectric-List: Re: How is it I get a shock from an iPod? From: "Eric M. Jones" > Putting a meter between the lock switch and ground I measure an invigorating 60VAC. Between the neutral of the power strip to any other ground is zero, so I figure the power strip is wired correctly. Inverting the cube (it's not polarized) makes no difference, still 60VAC. The actual ground to neutral is never zero, but it should be less than 3VAC. But this is probably not the problem. Sounds like you have a bad charger, Dave. And don't think because this is a common problem that it is acceptable. They could all be bad. do not archive -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=425452#425452 ________________________________ Message 6 _____________________________________ Time: 06:51:42 AM PST US Subject: AeroElectric-List: Re: How to decide if a heat sink is required for a Rect Br From: "Eric M. Jones" I sell very nice Power_Deuce_Schottkys for the Z-19 half bridges or any other purpose. Very low Vf, modest heat sink included. -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=425453#425453 Attachments: http://forums.matronics.com//files/power_deuce_schottky_manual_269.pdf ________________________________ Message 7 _____________________________________ Time: 07:11:04 AM PST US Subject: AeroElectric-List: Vintage Electronics at ShopGoodwill.com From: "Eric M. Jones" Do Not Archive A couple weeks ago someone wanted to sell off a TV repair inventory and it reminded me that my favorite "vintage electronics" market was the vintage electronics (and miscellaneous) pages of ShopGoodwill.com. There among the odd junk you can find Simpson 360/370's, old oscilloscopes, test gear and all manner of stuff you wish you hadn't tossed. I keep thinking I should email a note to Bob N., saying, "BOB!, you really should see this!" But I have restrained myself... so far. Last week I bid on a Curta Type I calculator. Cheeeeez.......... I just grabbed a 4DX Flightcom headset (brand new) for $49. Remember it all goes to charity. -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=425454#425454 ________________________________ Message 8 _____________________________________ Time: 07:17:56 AM PST US Subject: AeroElectric-List: Re: Vintage Electronics at ShopGoodwill.com From: "donjohnston" Eric M. Jones wrote: > Last week I bid on a Curta Type I calculator. Cheeeeez.......... A Curta Type I? How much did you bid and did you get it??? Read this topic online here: http://forums.matronics.com/viewtopic.php?p=425456#425456 ________________________________ Message 9 _____________________________________ Time: 07:19:20 AM PST US Subject: AeroElectric-List: Re: iPod shocks From: GLEN MATEJCEK > > Hi Guys- it sounds like you are getting a half wave tickle, which could > imply that the guts of the device are intended for a polarized plug while > the polarized plug itself is absent. If that is the case, each time you > plug in you would have a 50 / 50 chance of getting a have wave zap, 60v > here and 110 v for Etienne. I'd repeat the V measurement excercise twice, > once with each plug / recceptacle orientation. If you get 1/2 line V one > way and zero the other, there you go. > > > Time: 10:51:06 PM PST US > From: Dave Saylor > Subject: AeroElectric-List: How is it I get a shock from an iPod? > > Here's a non-aviation question for the group. Unless you fly with an iPod, > I guess. > > Background: > > My son complained today that he got shocked by an iPod. FWIW, it's a 5th > gen nano plugged into an Apple USB charging cube by an Apple charging > cord--not knock-off parts. First I said yeah, right...but he insisted so > like an idiot I figured I'd show him how that was impossible....and of > course I got shocked too. Not as strong as 120VAC but enough to get my > attention. > > We were both barefoot (key, I think...) on a concrete slab, in the garage. > It happened when either of us touched the metal lock switch. I've never > had any issues with the power strip we were using. > > Putting a meter between the lock switch and ground I measure an > invigorating 60VAC. Between the neutral of the power strip to any other > ground is zero, so I figure the power strip is wired correctly. Inverting > the cube (it's not polarized) makes no difference, still 60VAC. > > I tried a few things: different plug, no shock. Different cord, no shock. > Different cube, no shock. I went back to the original combination: > BZZZZT. So it is repeatable. > > There's an Apple support document describing the possibility of static > shock when using their device. This was not your typical > feet-on-carpet-touch-a-doorknob static shock. It was sustained as long as I > touched the lock switch. > > The iPod works and charges just fine except for that particular combination > of parts. > > Questions: > > In general, how is it that an iPod can give me an electric, non-static > shock? I thought that USB was only 5V. How does more than 5V get into the > system? Or more appropriately, how does it get out of the system? Could > this happen from a 12V system, or is part of the 120V getting through? > > Thanks for tolerating a non-airplane topic, > > --Dave Saylor > > ________________________________ Message 17 > ____________________________________ > > > Time: 11:48:32 PM PST US > Subject: Re: AeroElectric-List: How is it I get a shock from an iPod? > From: Etienne Phillips > > Hi Dave > > I think it's an Apple thing - I get zapped by my aluminium Macbook Pro, > exactly how you describe it - when it's plugged in. Sometimes it's actually > painful, since the skin in the inner arms is pretty sensitive! I don't know > if it's any different here in a 220V country, but I'd really like to get to > the bottom of it. It's happened at multiple locations, which leads me to > believe that it's also not affected by the supply wiring. > > Thanks > Etienne > > > On 25 June 2014 07:49, Dave Saylor > wrote: > > > Here's a non-aviation question for the group. Unless you fly with an > > iPod, I guess. > > > > Background: > > > > My son complained today that he got shocked by an iPod. FWIW, it's a 5th > > gen nano plugged into an Apple USB charging cube by an Apple charging > > cord--not knock-off parts. First I said yeah, right...but he insisted so > > like an idiot I figured I'd show him how that was impossible....and of > > course I got shocked too. Not as strong as 120VAC but enough to get my > > attention. > > > > We were both barefoot (key, I think...) on a concrete slab, in the > garage. > > It happened when either of us touched the metal lock switch. I've never > > had any issues with the power strip we were using. > > > > Putting a meter between the lock switch and ground I measure an > > invigorating 60VAC. Between the neutral of the power strip to any other > > ground is zero, so I figure the power strip is wired correctly. Inverting > > the cube (it's not polarized) makes no difference, still 60VAC. > > > > I tried a few things: different plug, no shock. Different cord, no > shock. > > Different cube, no shock. I went back to the original combination: > > BZZZZT. So it is repeatable. > > > > There's an Apple support document describing the possibility of static > > shock when using their device. This was not your typical > > feet-on-carpet-touch-a-doorknob static shock. It was sustained as long > as I > > touched the lock switch. > > > > The iPod works and charges just fine except for that particular > > combination of parts. > > > > Questions: > > > > In general, how is it that an iPod can give me an electric, non-static > > shock? I thought that USB was only 5V. How does more than 5V get into > the > > system? Or more appropriately, how does it get out of the system? Could > > this happen from a 12V system, or is part of the 120V getting through? > > > > Thanks for tolerating a non-airplane topic, > > > > --Dave Saylor > > > > * > > > > > > * > > > > > > ________________________________ Message 10 ____________________________________ Time: 07:45:49 AM PST US From: Daniel Hooper Subject: Re: AeroElectric-List: Re: iPod shocks The puzzling thing is that there should be no path for these kinds of shocks, no matter what... See Ken Shirriff's teardown of an apple charger here: http://www.righto.com/2012/05/apple-iphone-charger-teardown-quality.html and here: http://www.righto.com/2014/05/a-look-inside-ipad-chargers-pricey.html Is the voltage between neutral and ground zero *when it's plugged in*? I wonder if you don't have some resistance there or something that develops a voltage only when there is a load applied. Very odd. On Jun 25, 2014, at 9:18 AM, GLEN MATEJCEK wrote: > Hi Guys- it sounds like you are getting a half wave tickle, which could imply that the guts of the device are intended for a polarized plug while the polarized plug itself is absent. If that is the case, each time you plug in you would have a 50 / 50 chance of getting a have wave zap, 60v here and 110 v for Etienne. I'd repeat the V measurement excercise twice, once with each plug / recceptacle orientation. If you get 1/2 line V one way and zero the other, there you go. > > > > > > Time: 10:51:06 PM PST US > From: Dave Saylor > Subject: AeroElectric-List: How is it I get a shock from an iPod? > > Here's a non-aviation question for the group. Unless you fly with an iPod, > I guess. > > Background: > > My son complained today that he got shocked by an iPod. FWIW, it's a 5th > gen nano plugged into an Apple USB charging cube by an Apple charging > cord--not knock-off parts. First I said yeah, right...but he insisted so > like an idiot I figured I'd show him how that was impossible....and of > course I got shocked too. Not as strong as 120VAC but enough to get my > attention. > > We were both barefoot (key, I think...) on a concrete slab, in the garage. > It happened when either of us touched the metal lock switch. I've never > had any issues with the power strip we were using. > > Putting a meter between the lock switch and ground I measure an > invigorating 60VAC. Between the neutral of the power strip to any other > ground is zero, so I figure the power strip is wired correctly. Inverting > the cube (it's not polarized) makes no difference, still 60VAC. > > I tried a few things: different plug, no shock. Different cord, no shock. > Different cube, no shock. I went back to the original combination: > BZZZZT. So it is repeatable. > > There's an Apple support document describing the possibility of static > shock when using their device. This was not your typical > feet-on-carpet-touch-a-doorknob static shock. It was sustained as long as I > touched the lock switch. > > The iPod works and charges just fine except for that particular combination > of parts. > > Questions: > > In general, how is it that an iPod can give me an electric, non-static > shock? I thought that USB was only 5V. How does more than 5V get into the > system? Or more appropriately, how does it get out of the system? Could > this happen from a 12V system, or is part of the 120V getting through? > > Thanks for tolerating a non-airplane topic, > > --Dave Saylor > > ________________________________ Message 17 ____________________________________ > > > Time: 11:48:32 PM PST US > Subject: Re: AeroElectric-List: How is it I get a shock from an iPod? > From: Etienne Phillips > > Hi Dave > > I think it's an Apple thing - I get zapped by my aluminium Macbook Pro, > exactly how you describe it - when it's plugged in. Sometimes it's actually > painful, since the skin in the inner arms is pretty sensitive! I don't know > if it's any different here in a 220V country, but I'd really like to get to > the bottom of it. It's happened at multiple locations, which leads me to > believe that it's also not affected by the supply wiring. > > Thanks > Etienne > > > On 25 June 2014 07:49, Dave Saylor > wrote: > > > Here's a non-aviation question for the group. Unless you fly with an > > iPod, I guess. > > > > Background: > > > > My son complained today that he got shocked by an iPod. FWIW, it's a 5th > > gen nano plugged into an Apple USB charging cube by an Apple charging > > cord--not knock-off parts. First I said yeah, right...but he insisted so > > like an idiot I figured I'd show him how that was impossible....and of > > course I got shocked too. Not as strong as 120VAC but enough to get my > > attention. > > > > We were both barefoot (key, I think...) on a concrete slab, in the garage. > > It happened when either of us touched the metal lock switch. I've never > > had any issues with the power strip we were using. > > > > Putting a meter between the lock switch and ground I measure an > > invigorating 60VAC. Between the neutral of the power strip to any other > > ground is zero, so I figure the power strip is wired correctly. Inverting > > the cube (it's not polarized) makes no difference, still 60VAC. > > > > I tried a few things: different plug, no shock. Different cord, no shock. > > Different cube, no shock. I went back to the original combination: > > BZZZZT. So it is repeatable. > > > > There's an Apple support document describing the possibility of static > > shock when using their device. This was not your typical > > feet-on-carpet-touch-a-doorknob static shock. It was sustained as long as I > > touched the lock switch. > > > > The iPod works and charges just fine except for that particular > > combination of parts. > > > > Questions: > > > > In general, how is it that an iPod can give me an electric, non-static > > shock? I thought that USB was only 5V. How does more than 5V get into the > > system? Or more appropriately, how does it get out of the system? Could > > this happen from a 12V system, or is part of the 120V getting through? > > > > Thanks for tolerating a non-airplane topic, > > > > --Dave Saylor > > > > * > > > > > > * > > > > > > > > > ========== > - > ric-List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List > ========== > MS - > k">http://forums.matronics.com > ========== > e - > -Matt Dralle, List Admin. > t="_blank">http://www.matronics.com/contribution > ========== > > > > > > > > ________________________________ Message 11 ____________________________________ Time: 07:47:15 AM PST US Subject: Re: AeroElectric-List: Re: iPod shocks From: Etienne Phillips Hi Glen I've tried swapping the plug around, with no improvement. The charger is supplied with a non-polarized 2-pin plug on the end, so it's being used as intended (certainly as intended by Apple, but maybe not by the people who designed the insides - if not Apple). This isn't an isolated incident, it happened on my previous Macbook Pro (7 years ago) and happened in the iStore last week on the latest generation stuff. I'm not saying it's right, as it certainly isn't pleasant - but it doesn't seem as though Apple is taking complaints about it too seriously. I'll try and remember to take a voltage measurement tonight to see how bad it is. What is interesting is that it zaps me no matter how well I'm insulated from the floor. Etienne On 25 June 2014 16:18, GLEN MATEJCEK wrote: > Hi Guys- it sounds like you are getting a half wave tickle, which could >> imply that the guts of the device are intended for a polarized plug while >> the polarized plug itself is absent. If that is the case, each time you >> plug in you would have a 50 / 50 chance of getting a have wave zap, 60v >> here and 110 v for Etienne. I'd repeat the V measurement excercise twice, >> once with each plug / recceptacle orientation. If you get 1/2 line V one >> way and zero the other, there you go. > > ________________________________ Message 12 ____________________________________ Time: 08:03:31 AM PST US Subject: Re: AeroElectric-List: Re: iPod shocks From: James Kilford Hi Etienne, Same here in the UK, but with a Toshiba laptop. Some of the black coating has rubbed off the left-hand front corner of the laptop, revealing a tiny 1x1mm bit of metal... right where my wrist is. When it's plugged in, I get a shock from it; when it's not, I don't. Here in the UK, all sockets are wired the same way, with specific L, N & E terminals. FWIW. James p.s. a further oddity. If I run my finger along the laptop, for example next to the mousepad, it sort of "drags" when the laptop's plugged in... when it's not, there's no friction at all. Go figure! On 25 June 2014 15:46, Etienne Phillips wrote: > Hi Glen > > I've tried swapping the plug around, with no improvement. The charger is > supplied with a non-polarized 2-pin plug on the end, so it's being used as > intended (certainly as intended by Apple, but maybe not by the people who > designed the insides - if not Apple). > > This isn't an isolated incident, it happened on my previous Macbook Pro (7 > years ago) and happened in the iStore last week on the latest generation > stuff. I'm not saying it's right, as it certainly isn't pleasant - but it > doesn't seem as though Apple is taking complaints about it too seriously. > > I'll try and remember to take a voltage measurement tonight to see how bad > it is. What is interesting is that it zaps me no matter how well I'm > insulated from the floor. > > Etienne > > > On 25 June 2014 16:18, GLEN MATEJCEK wrote: > >> Hi Guys- it sounds like you are getting a half wave tickle, which could >>> imply that the guts of the device are intended for a polarized plug while >>> the polarized plug itself is absent. If that is the case, each time you >>> plug in you would have a 50 / 50 chance of getting a have wave zap, 60v >>> here and 110 v for Etienne. I'd repeat the V measurement excercise twice, >>> once with each plug / recceptacle orientation. If you get 1/2 line V one >>> way and zero the other, there you go. >> >> >> >> * > > > * > > ________________________________ Message 13 ____________________________________ Time: 10:44:16 AM PST US Subject: Re: AeroElectric-List: How is it I get a shock from an iPod? From: Eric Page Dave, I think it's likely that the charging cube you have, though it may look like genuine Apple, is actually a knockoff. There have been many examples of th ese coming from China, and they almost never have the same safety-minded des ign as the genuine article. They look virtually identical, but the insides a re a joke by comparison. If it is an Apple, it clearly has a manufacturing d efect. Obviously, these things convert 120VAC to 5VDC. Believe it or not, the proc ess involves AC voltages much higher than line voltage. If the device doesn 't have proper allowances in its design for creepage and clearance (distance between high and low voltage sections), it can be a death trap. I *STRONGL Y* recommend that you throw the offending charger away *IMMEDIATELY* and get a new one. I would stick with either a genuine Apple part, or one of the w ell-known aftermarket brands like Belkin. You should never feel an AC shock from any consumer electronics device. Eve r. Eric P.S. Crack the cube open and take a couple pictures of the insides before y ou toss it. It's pretty easy to tell the difference between Apple and knock off. On Jun 25, 2014, at 12:49 AM, Dave Saylor wrote: > Here's a non-aviation question for the group. Unless you fly with an iPod , I guess. > > Background: > > My son complained today that he got shocked by an iPod. FWIW, it's a 5th g en nano plugged into an Apple USB charging cube by an Apple charging cord--n ot knock-off parts. First I said yeah, right...but he insisted so like an i diot I figured I'd show him how that was impossible....and of course I got s hocked too. Not as strong as 120VAC but enough to get my attention. > > We were both barefoot (key, I think...) on a concrete slab, in the garage. It happened when either of us touched the metal lock switch. I've never h ad any issues with the power strip we were using. > > Putting a meter between the lock switch and ground I measure an invigorati ng 60VAC. Between the neutral of the power strip to any other ground is zer o, so I figure the power strip is wired correctly. Inverting the cube (it's n ot polarized) makes no difference, still 60VAC. > > I tried a few things: different plug, no shock. Different cord, no shock. Different cube, no shock. I went back to the original combination: BZZZZ T. So it is repeatable. > > There's an Apple support document describing the possibility of static sho ck when using their device. This was not your typical feet-on-carpet-touch- a-doorknob static shock. It was sustained as long as I touched the lock swit ch. > > The iPod works and charges just fine except for that particular combinatio n of parts. > > Questions: > > In general, how is it that an iPod can give me an electric, non-static sho ck? I thought that USB was only 5V. How does more than 5V get into the syst em? Or more appropriately, how does it get out of the system? Could this h appen from a 12V system, or is part of the 120V getting through? > > Thanks for tolerating a non-airplane topic, > > --Dave Saylor ________________________________ Message 14 ____________________________________ Time: 07:12:14 PM PST US From: Dave Saylor Subject: Re: AeroElectric-List: Re: iPod shocks Thanks to everyone who replied. This is such a great resource, I never get tired of the discussion. I did some more checking. My garage wiring seems to be fine. Can't find any fault there. I really do appreciate the concern, you guys are great. As for the half wave, even with polarity reversed, same effect. I tried a couple more chargers. A different Belkin charger gives me a 45V potential to ground. I have one of the dedicated USB receptacles that wires into a wall plug. It only gives me about 3V, which I figure is maybe just noise. And I tried a few more locations for the chargers. They seem to give the same result no matter where they're plugged in. Same result with two iPods and an iPhone. Nothing, though, with an iPad that uses the new type of mini plug. So the problem seems to be in the charger, some worse than others. I think the big difference was being barefoot on the concrete slab. That gave a great path to ground, courtesy of yours truly. I'm getting a new charger! --Dave On Wed, Jun 25, 2014 at 8:02 AM, James Kilford wrote: > Hi Etienne, > > Same here in the UK, but with a Toshiba laptop. Some of the black coating > has rubbed off the left-hand front corner of the laptop, revealing a tiny > 1x1mm bit of metal... right where my wrist is. When it's plugged in, I get > a shock from it; when it's not, I don't. Here in the UK, all sockets are > wired the same way, with specific L, N & E terminals. > > FWIW. > > James > > p.s. a further oddity. If I run my finger along the laptop, for example > next to the mousepad, it sort of "drags" when the laptop's plugged in... > when it's not, there's no friction at all. Go figure! > > > On 25 June 2014 15:46, Etienne Phillips > wrote: > >> Hi Glen >> >> I've tried swapping the plug around, with no improvement. The charger is >> supplied with a non-polarized 2-pin plug on the end, so it's being used as >> intended (certainly as intended by Apple, but maybe not by the people who >> designed the insides - if not Apple). >> >> This isn't an isolated incident, it happened on my previous Macbook Pro >> (7 years ago) and happened in the iStore last week on the latest generation >> stuff. I'm not saying it's right, as it certainly isn't pleasant - but it >> doesn't seem as though Apple is taking complaints about it too seriously. >> >> I'll try and remember to take a voltage measurement tonight to see how >> bad it is. What is interesting is that it zaps me no matter how well I'm >> insulated from the floor. >> >> Etienne >> >> >> >> On 25 June 2014 16:18, GLEN MATEJCEK wrote: >> >>> Hi Guys- it sounds like you are getting a half wave tickle, which could >>>> imply that the guts of the device are intended for a polarized plug while >>>> the polarized plug itself is absent. If that is the case, each time you >>>> plug in you would have a 50 / 50 chance of getting a have wave zap, 60v >>>> here and 110 v for Etienne. I'd repeat the V measurement excercise twice, >>>> once with each plug / recceptacle orientation. If you get 1/2 line V one >>>> way and zero the other, there you go. >>> >>> >>> >>> * >> >> ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List >> tp://forums.matronics.com >> _blank">http://www.matronics.com/contribution >> >> * >> >> > * > > > * > > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.