USB Socket on Laptop

[DerbyBorn]

I worry about using the socket for charging in case the lead develops a short.

What would happen if I did plug in a shorted lead or a faulty device to the

5v USB supply? Is there any protection?

[Harry Bloomfield]

DerbyBorn pretended :

USB outlets are current limited to a set maximum output, so no damage would ensue from them being shorted or any attempt to overload them.

Some are capable of 500ma, 1amp, or even more. 500mA is common on PC's and laptops. The devices you plug in also have their own current input protection, so a device which perhaps needs 500mA will draw that and no more, even if plugged into a USB outlet of 3amps capability.

[Andy Burns]

Some machines measure the current, and shutdown the port and display an "over-current" warning if a device takes more than the amount it has negotiated (I've not seen that behaviour for a few years though) I presume most have polyfuses these days.

[Tim Watts]

In a computer the socket is well protected against most common eventualities.

Wall wart chargers vary considerably!

[Tim Watts]

Subject to more recent changes, the USB power delivery spec limited current to 100mA unless the device negotiated a higher amount.

[newshound]

I *sometimes* think about wear and tear on the socket although I have never had one fail.

Thanks to the EU, I now have plenty of USB wall warts, most of them nice small switched mode supplies so I generally use these.

But as others have said, I'd have no concerns about charging from the laptop if necessary from the protection viewpoint.

[Mike Tomlinson]

En el artículo , DerbyBorn escribió:

Yes.

What has this got to do with DIY?

[John Rumm]

Yes, the power is disconnected, and you get a warning on screen telling you that a device is drawing more than the allowed amount of current.

[DerbyBorn]

Mike Tomlinson wrote in news: [e-mail]:

A PC group are too focused on software rather than electrical practicalities.

[Graham.]

My Dell puts up a balloon notification on the taskbar when a USB port draws too much current.

The first PC I owned that had USB support had 22mm wire ended glass fuses soldered onto the header PCB!

[Davey]

I had a thumbdrive which wore out its blade contact, either that or something got loose inside; but as it was a solid item, I doubt that, so I think it was the connector. It got lots of use, too, so wearing out was not a big surprise.

[Mike Tomlinson]

En el artículo , DerbyBorn escribió:

Pretty feeble.

Try uk.comp.homebuilt.

[DerbyBorn]

Mike Tomlinson wrote in news: [e-mail]:

I would feel obliged to trawl through months of questions to see if it had been covered. I have a good recall of what I have already seen on this group.

[Brian-Gaff]

Well my old Dell tells me that the current on the usbhas exceeded the supply limit and I need to buy a self powered hub to plug other things in to it. Brian

[DerbyBorn]

"Brian-Gaff" wrote in news:mqfmad$in8$ [e-mail]:

Thanks Brian - and mine is a Dell - an Inspiron N5010.

[Davey]

It's a lot more D-I-Y than a journey through Sellafield. Unless you have your own nuclear reactor, that it. Or problems with iPhones, or nostalgia, aka the Good Old Days. Or many other subjects that get covered on this NG. Why pick on this one?