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#31 |
Zealot
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Device: DBoox Max,Galaxy note 10.1 & 3,LE1700 tablet,sony PRS-500,iRex DR1000S
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I also notice the same on my reader. (at 230V). I sometimes get the same type of vibrations on other devices (laptop, for example), and usually unplugging the power plug, turning it upside-down, and plugging it back into the wall helps. It didn't help on my reader, though. But try it on yours.
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#32 |
eBook Enthusiast
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I've just tried measuring it on mine - no voltage reading beyond random noise on the multimeter. I'm convinced it's just a mains frequency vibration, which is very common in all sorts of devices.
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#33 | |
dstampe
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Join Date: Jan 2007
Location: Canada
Device: Sony PRS-500
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Quote:
If it leaks a little, it could leak a lot, the insulation to the AC power is compromised. Given that you are feeling a "tingle" and are not touching something that's grounded, there is the possibility you could get a more severe shock if you were touching something grounded. You really can't get any sort of shock from 5.2V by itself, unless you (a) place it in your mouth or (b) penetrate the skin with needles or an open wound, The fact that a meter does not read a high voltage from the metal to ground just means that the leakage path resistance is high--for now. (Voltmeters have their own resistance that drops the voltage measured through a high resistance). I'm not saying the insulation in the charger will break down completely, but it's not comforting to see any sort of leakage. There are possible design decisions that could have been made in the power pack circuitry that could create a high-resistance (or capacitive) leakage path. Standards allow up to 1 milliamp (more than a "tingle" of leakage measured at twice the rated AC voltage. So it's possible that the designers of the power pack made the decision to allow some leakage (at the edge of detectability, say 0.1 milliamp) to save a few cents. Not very professional, if you ask me. Anyway, based on international safety standards (I've had the not-do-fun experiennce of pushing a few products through tha regulation nughtmare), I'd be cautious. Any double-insulated device that causes a tingle when not soaking wet is potentially dangerous. If you must use it, I would: - plug the Reader in with the charger unplugged, then place it in a safe plage, then plug the charger it. - Minimize contact with the Reader while charging - Get a replacement charger or a use a different charging method. Last edited by dstampe; 03-17-2007 at 07:47 AM. |
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#34 |
Gizmologist
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Location: Republic of Texas Embassy at Jackson, TN
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Given the fact that meters (which are designed to measure well into the millivolt range) are showing nothing no voltage, I'm entirely satisfied that this is a vibration, and not leakage -- I don't get any tingle when I place my finger across the contacts in a 9 volt battery, for instance, and that's way above the level of meter noise, and it's capable of putting out a good bit more than a single milliamp.
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#35 |
Gadget Force®
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Actually I measured the current from me touching the reader with one hand en the other hand holding the ground contact in the wallsocket. The current is: 0.03mA. So like I said before it is very normal to have some noise going over the DC output if the charger is cheap made without to many filters. I have the same with my laptop BTW, also a nice tingle. :P
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#36 | |
Groupie
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Device: Sony PRS-500
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#37 |
Gadget Force®
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That's weird because I didn't get more than 0.9VAC. 1.1mA through your DMM could be 0.03mA through my body considering you DMM is a very low resistor(shunt) and my body is much higher. I don't know how it can be that you measure 22VAC.
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#38 |
Gizmologist
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22 VAC you should definitely feel, no question at all.
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#39 | |
Groupie
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#40 |
Gadget Force®
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I took my Reader to my work and we measured it with some real high tech stuff. There is actually 100VAC on the DC ground when connecting the charger to 230VAC. But with a very low current so it's not harmfull. With a little load the 100VAC drops down until under 5VAC. This comes from the netfilter that is inside the charger. RSaunders is right that it is caused by a capacitor, but it's not really leaking in a bad way. It's the capacitor used as a netfilter. Like I said before you can feel the same on the casing of a PC when you connect it to a non-grounded wallsocket.
Last edited by diabloNL; 03-23-2007 at 08:44 PM. |
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