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newb.
02-05-2007, 10:06 AM
Hey guys, it's me again :D

Just a few questions that have been lingering in my cranium.

1) Is it true that all laptops use a transformer instead of a PSU?

2) Why will a magnet destroy components in your computer if the two come in contact?

Thanks. :cool:

memphis
02-05-2007, 10:31 AM
Question 1 + Question 2 = Answer 3 = GOOGLE

:2cents:

Sweep
02-05-2007, 10:39 AM
Were you set questions as homework?

Pete O'Neil
02-05-2007, 11:04 AM
1) Is it true that all laptops use a transformer instead of a PSU?

Wouldn't a PSU just be a kind of transformer? ;)

pctek
02-05-2007, 12:50 PM
1) Is it true that all laptops use a transformer instead of a PSU?

2) Why will a magnet destroy components in your computer if the two come in contact?


http://www.howstuffworks.com/power-supply.htm

http://www.pcworld.com/article/id,116572-page,1/article.html

drcspy
02-05-2007, 02:45 PM
a psu transforms 240v a/c to 12v,5v,3.3v and etc DC....so it IS a transformer anyway.......a lappy 'external' powerpack is a very similar device.....

Burnzee
03-05-2007, 12:03 AM
The first question suggests you are confusing the two different types of power supplies.

The first basic power supply uses a TRANSFORMER to convert 240vac to a lower voltage. It then feeds this to diodes to change this ac to dc. Finally through a capacitor to smooth the voltage. A more complex circuit would use a voltage regulator to control the output. These circuits while cheap to make, suffer from many shortfalls, bulk being one of them. Not the thing for a portable lappie!!

The second, a switchmode power supply uses a TRANSFORMER too but in a different way. A electronic switch chops up the 240vac at a high frequency before passing it through a transformer. The output from this is then fed to diodes, capacitor/s and other smoothing components. The resulting output is then a steady dc voltage suitable for your laptop. The main advantage is the transformer can be smaller and weigh less.

NOTE: These explainations are simplified and to really understand them further reseach is required.

The second question is a bit harder to understand but one thing to consider is if the magnets are moving across a transformer, (coil of wire), they could in theroy at least, generate a voltage. This is exactly how generators and altenators work.

Billy T
03-05-2007, 12:54 AM
Hey guys, it's me again :D

Just a few questions that have been lingering in my cranium.

1) Is it true that all laptops use a transformer instead of a PSU?

2) Why will a magnet destroy components in your computer if the two come in contact?

Thanks. :cool:
Keeping it really simple:

1) A PSU is simply a Power Supply Unit, and in the context of your question, all PSU's incorporate a transformer.

2) A magnet won't do jack to your computer, not unless you throw it through the screen, or attach really powerful little beasties (5-6 gauss) all over your HDD. Then they just might cause a hiccup or two, but they might not too.

Cheers

Billy 8-{)

pctek
03-05-2007, 06:20 AM
Hmm. Powerful magnets.
How do you tell?

Husband has a magnet thats about 6 inches by 4 inches.
Big meaty thing, handy for finding dropped screws and fishing nails out of the fireplace etc.

We tried it once, waved it all over an old drive, this was years ago, actually waved probably isn't the word, you wave the magnet and it slams into the metal and has to be prised off.

It did stuff the drive up.

Billy T
03-05-2007, 07:41 AM
Hmm. Powerful magnets.
How do you tell?
The most powerful commonly available magnets I have tested were small 8mm diameter "rare-earth" buttons used to hold a 365-day joke calendar to a metal surface. They measured in excess of 6 kilogauss. When 8 of them are stacked, you can't physically pull them apart without sliding them sideways.

Judge the strength by whether you can physically force the like poles into face to face contact without bracing one hand against the other while using a third surface as a support. It is virtually impossible to do this for magnets stronger than 100 gauss, and the little 6 kilogauss babies can't be forced together by hand no matter how strong you are or how well you brace your hands. The most powerful types are rare-earth doped ferrites like neodymium-iron-boron. They are the Charles Atlas of the magnet world.

Typical "plaything" ferrite magnets have a strength of about 100 to 400 gauss and plain steel magnets are in the "also-ran" skinny weakling category.

Cheers

Billy 8-{)

dugimodo
03-05-2007, 11:18 AM
well everyone beat me too it :) but.

1) without worrying about it too much laptops have external PSU's supplying a single DC voltage which is changed to other voltages inside the laptop.
Desktops have an internal PSU which supplies multiple different voltages.
A transformer is a pair (or more) of coils which 'transform' one AC voltage to another and is used in the PSU as one of the components, however laptop psu's are electronic and don't necesarily contain tranformers

2) mostly it won't, but information on floppy drives and hard drives is stored magnetically so getting them too close to a magnetic field has the potential of corrupting the data, or if the magnet is strong enough permantley damaging the disk