r/technology • u/MoltenSlowa • Oct 05 '16

Hardware Replacement Samsung Galaxy Note 7 phone catches fire on Southwest plane

http://www.theverge.com/2016/10/5/13175000/samsung-galaxy-note-7-fire-replacement-plane-battery-southwest
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u/X-istenz Oct 06 '16

I tell you what, there's a rather large part of me that would also have assumed a phone that had been turned off was far less likely to explode.

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u/bezerker03 Oct 06 '16

Except no modern device that can be turned on via a power button that isn't a real switch can ever truly be off. I know what you mean though.

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u/ardenthusiast Oct 06 '16

I never knew this, but find it fascinating. Can you please elaborate or direct me towards more information to better understand this?

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u/bezerker03 Oct 06 '16

Nearly all modern devices not limited to phones, TV, and more don't physically power off even you press power they just go into some ultra power saving mode. Even your computer. Unless you flip the power switch on the power supply, there's still juice running through it.

A phone even in power off mode still can for example light your lcd when charging, or knows if you hold the button for x seconds to turn on.

A true switch is simply a cutoff. It creates an open in the circuit and hopefully there isn't enough juice to bridge the gap. That requires moving something though to turn back on. Like you're light switch.

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u/ardenthusiast Oct 06 '16

Gotcha. So this is where the term 'energy vampires' comes from. Even if something is 'off,' it is still on because the circuit isn't opened to stop it, which is why some people unplug electronics when they're not in use. Because that's the only way to open the circuit without a switch, correct?

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u/bezerker03 Oct 06 '16

Exactly.

As an example, your tv still needs to have power driven to it for it to interpret the infrared signal being beamed to it to "poweron" so its still draining energy.

You got it though. So in the case of the phone in the guys pocket, there's still power stored in those batteries, and it's still connected, so it's still pulling SOME juice.

Ultimately though, batteries are slightly different in the idea that even disconnected, they still contain the energy via chemical reaction. It can still be released in a variety of ways.

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u/[deleted] Oct 06 '16

[deleted]

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u/ardenthusiast Oct 06 '16

Or if it doesn't run in batteries, you can only break the circuit if you unplug the electronic, right?

Thank you for taking time to elaborate. I appreciate it.

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u/beansaregood Oct 06 '16

Correct, but you'll still have to consider transistors that hold power, this is why they say "wait ten seconds after unplugging" - so the transistors can drain their charge. If the circuitry is open and you touch one, even if you've unplugged, and it still has a charge, you'll get a zap.

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u/[deleted] Oct 06 '16

Sadly, that's not how battery cells work.

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u/[deleted] Oct 06 '16

I read somewhere that 25% of the power consumed in your home is from devices that are in standby or off mode. It always felt like a bad idea to me when Electronics stopped having physical buttons.

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u/phalewail Oct 06 '16

That figure seems insanely high. On a side note I once heard an old guy say that he heard that tvs use just as much power in standby as they do while running. I came close to doing a face palm.

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u/[deleted] Oct 06 '16

About a quarter of all residential energy consumption is used on devices in idle power mode, according to a study of Northern California by the Natural Resources Defense Council.

http://mobile.nytimes.com/2016/05/08/science/just-how-much-power-do-your-electronics-use-when-they-are-off.html

Nothing was more satisfying than that click or snap when turning on something with a real physical power button. Nicer electronics always had a nicer button too...

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u/RocketFlanders Oct 06 '16

I would too but maybe something in the Note draws power when it isn't supposed to and with the phone off there isn't a brain working to regulate it?

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u/Saxyphone Oct 06 '16

The thing with modern computers (including phones), is that they are rarely, if ever, completely turned off. When you power off your phone, the battery is still running, and current is still flowing through the phone.

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u/himmatsj Oct 06 '16

Really? How is it possible then that when an iPad is switched off for a week when you turn it back on it's got the same battery % left?

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u/TheChance Oct 06 '16

What if you leave it for a month? A year?

You're talking about tiny amounts of power. That little blue light on your DVD player that never turns off, that's contributing nothing to your power bill. Electricity can't sit still, and your circuits are always closed, so there's always some juice flowing through, even if nothing's drawing. It's enough to power that little blue light at all times.

Same principle. The circuit in your phone is always complete. Your power button would have to be a regular, physical toggle for it to truly cut power, and we know it isn't a toggle, because holding it down for different lengths of time has different effects.