How does my laptop know that I have a different brand power supply plugged in.

thatsmessedup

Junior Member
Jul 2, 2015
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I have lots of high quality power supplies but my laptop refuses to charge on any except the one it came with. How can it even know?
 

Harvey

Administrator<br>Elite Member
Oct 9, 1999
35,057
67
91
Power bricks have different voltage and current rating, and they differ as to whether the sleve or inner contact is positive. Also, the outer diameter of the connector from various power supplies can vary.

Start by knowing the voltage and amperage requirements for your machine. The info should be on your original power brick, or you can check the manual or the manufacturer's site.

Any supply that provides the required voltage and AT LEAST the required current should work. A supply that provides more than the minimum required current is fine.

And be sure you know which terminal is supposed to be positive and which is ground.
 

VirtualLarry

No Lifer
Aug 25, 2001
56,574
10,211
126
Dell power bricks have a third "center pin", that is a data connector, that allows the laptop and the power brick to communicate, and the laptop verifies that you are using an official Dell power brick.
 

pitz

Senior member
Feb 11, 2010
461
0
0
Dell power bricks have a third "center pin", that is a data connector, that allows the laptop and the power brick to communicate, and the laptop verifies that you are using an official Dell power brick.

I'm pretty sure anyone can just call up Analog Devices (or similar) and order the chips. There's nothing magical or proprietary about it. Only thing is, it has to be a proper/compatible chip on the other end, and sometimes the less-than-scrupulous "Asian" manufacturers try to cheap out on even that.
 

MongGrel

Lifer
Dec 3, 2013
38,466
3,067
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I've owned two prebuilt computer i my life I think the first was a Packard Bell 386 P40 I think I upgraded to a P60 in 1990.

The second was a Dell about 3 years later, the RAM was Propietary and I haf to pay twice as much at the time to upgrade it, so I've been building my own ever since.
 

thatsmessedup

Junior Member
Jul 2, 2015
3
0
0
Dell power bricks have a third "center pin", that is a data connector, that allows the laptop and the power brick to communicate, and the laptop verifies that you are using an official Dell power brick.

Interesting. I think this was the tidbit of information I was looking for. I never noticed a third pin in any of my power supplies so it must be somewhat hidden.
 

lazybedone

Member
Apr 15, 2015
154
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0
Thank you so much! Its really helpful. My laptop had a problem 2 days ago with my power supply. Been very thankful to see this post! :)