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FoxyMX
21-12-2009, 10:43 AM
When a laptop is running on AC power, is it still possible for a plugged in device to receive a zap from power surges or spikes?

Some people seem to think that the AC power is going straight to the battery so that the laptop is running on battery power at all times, even when plugged in. :confused:

I don't believe this. What if the battery is dead, flat or not even in the laptop?

My thinking is that when the laptop is plugged in it is running on AC mains power only, regardless of whether there is a functional battery in it or not. I am right, of course, aren't I?

wratterus
21-12-2009, 10:52 AM
You are right.

FoxyMX
21-12-2009, 10:55 AM
Of course. As I always am. :p :p

Thanks. :thumbs:

wratterus
21-12-2009, 11:00 AM
:banana

pctek
21-12-2009, 11:14 AM
When a laptop is running on AC power, is it still possible for a plugged in device to receive a zap from power surges or spikes?



Of course.
You can kill things from power through a phone line too.

FoxyMX
21-12-2009, 11:22 AM
OK, well this is what someone has told me. Note that they are referring to when the laptop is plugged in to the mains.


For clarification, laptop computers always run off of DC power even if the laptop's battery isn't in the computer. The little black box on the laptop's power adapter cord coverts the 110 volt 60 cycle AC into the DC power used to charge the battery or run the computer. There is no AC current beyond the transformer in the computer's power adapter. Now as to whether or not a power surge could get past the adapter through the computer into the audio circuit and cause a surge in the audio cable is another matter.

wratterus
21-12-2009, 11:27 AM
That is true, I was thinking mains power rather than AC power when I replied to the first post. All notebook power supplies convert the power to DC (normally around 19v), but you can still get surges through the power supplies.

FoxyMX
21-12-2009, 11:39 AM
All notebook power supplies convert the power to DC (normally around 19v), but you can still get surges through the power supplies.

So a surge could zap a device that is plugged into the laptop? More specifically, an audio cable?

wratterus
21-12-2009, 11:40 AM
It is possible. Unlikely, but possible.

FoxyMX
21-12-2009, 11:47 AM
It's unlikely for one to be hit by lightening, but is it possible. That's enough for me. ;)

Thanks again. :thumbs:

hotkiwi
21-12-2009, 06:37 PM
And by the way, take your battery out if you work all day on the notebook.

or is this an urban myth too ??? (I mean reducing the number of charge cysles by remocing the battery)

Burnzee
22-12-2009, 10:39 AM
Hi FoxyMX


When a laptop is running on AC power, is it still possible for a plugged in device to receive a zap from power surges or spikes?


Yes, it's very possible for a plugged in device to get a zap from power surges or spikes but not likely in normal use. Get a zap catcher to help prevent this happening and save your lappie too.


Some people seem to think that the AC power is going straight to the battery so that the laptop is running on battery power at all times, even when plugged in.

The AC power is converted to a lower value DC voltage by the little black box you plug into the mains and the lappie. The black box contains a special type of circuitry called a Switched Mode Supply. From there it goes to your battery charge control circuit then to the battery. It also provides power to supply the laptop. Note this a parrallel cicuit not a series one. It does NOT go to the battery then out of the battery to the computer.


My thinking is that when the laptop is plugged in it is running on AC mains power only, regardless of whether there is a functional battery in it or not. I am right, of course, aren't I?


You are right but you simply put it the wrong way. Think what you meant to say was the laptop when is plugged in it is SUPPLIED by the mains only. The computer at no point runs on AC.


And by the way, take your battery out if you work all day on the notebook.

or is this an urban myth too ??? (I mean reducing the number of charge cycles by removing the battery)


Just want to clear this up too. This may have been true in the old days but it is bad advice with modern laptops. All lappies these days have a battery charge control circuit to charge the battery to it's optimium. A laptop battery last longer if it is fully charged (100%) or stored part charged at 40%.

Take the battery out and first you create a large hole where wild life - spiders, roaches, ants etc and dust can enter. Next your battery life is starting to decline unless you struck the magic 40%.

Removing the battery does not reduce the number of charge cycles, it actually increases them by one each time you put your battery back!!

Taking good care of your battery will give it long life. Avoid high tempertures.

Hope this helps.


BURNZEE

FoxyMX
22-12-2009, 04:42 PM
Cheers Burnzee. I always get tripped up by my electrickery terminology but glad to hear I was kind of on the right track. :p :cool: