USB power supplies.

Well yes, assuming you did not buy yours from a market trader, in which case its probably either a fake or dangerous. Brian

Those drawings are a bit of a waste of space. ;-) None of them really looks exactly like the one I'm talking about which, here, is the commonest small one. But the closest by those drawings would be the Mini-A, so perhaps the camera handbook is right after all. And they could have given the dimensions easily.

We have two tom-toms - one from about 4 years ago (mini USB) that I regularly charge from a motorola phone supply and a netbook, and the other from the last year (micro USB) from a different phone supply and the netbook. Both run from the supplied adaptors in the cars as well, and both seem quite happy with all the chargers - so I don't think they are that fussy.

Charles F

Micro USB looks like a squashed capital D from the business end. The ends of the D are a vertical bit below a sloped bit when you have the contacts at the bottom.

Mini USB has the rounded bits of the D reversed, and they're made from a sloped bit below a vertical bit when you have the contacts at the bottom. They're also a bit thicker top to bottom than MicroUSB

In practice differing voltages are largely interchangeable. Trouble is there's no way to know for sure when they are.

NT

Quite. I've never quite worked out why they seem to cost the same per unit. For a fraction of the capacity. Not like they're exactly rare, either.

That's definitely mini-USB-B. I just measured one. :)

micro-USB-B is 6.9 x 1.9+bumps mm. This is the euro-standard for small hand-held data device chargers.

So a C or D cell is the same price as an AA or AAA?

To make, pretty much. But they charge what the market will bear.

That applies to everything. However, equally, everything has a cost of materials and energy required to make and transport it. It is nonsense to say two similar products but made to a different scale cost the same.

Try asking your greengrocer for 10 pounds of apples for the same price as

I have 2 Nokia phones. The charger is the same voltage, but new one has a smaller plug that is easier to break.

When they are sold by weight? You need to try doing the shopping yourself one day.

No-one's yet mentioned the use of slightly above 5v in some USBs. It doesnt help with compatibility.

NT

In message , at 20:25:16 on Sun, 3 Aug

...

Let's just take this one as an example. The equipment in question is modern, and so are their remote controls. I have seen remote controls the same external size with 4xAAA rather than 2xAA, but that's even more ridiculous - not only do they require replacing more often, the cost is twice as much.

Then perhaps you need to avoid those pound shops where everything is the same price.

USB is a standard so yes pin outs are set. Note that powered USB devices have different current push capabilities, one of the pins dictates the max current available.

As someone pointed out iPhones are different ....... however EU is forcing all phone manufacturers (who need CE sales approval) to adopt standard USB. I think from 2015

Good move ... stop the myriad of chargers that seem to build up.

Not charger related - but 3 easily done 'wrong USB connections'

# On some devices the micro USB socket is not that sturdy and it is possible to insert plug upside down.

# You can plug standard USB plug into an Ethernet socket (not good)

# You can plug standard USB plug into a PC USB socket the wrong way round ...

Which would result in no connection, looking at the ones here.

Not good for the ethernet, maybe, as it would short it out and possibly bend the contacts, but no problem for the USB, unless it's one of the rare unshielded ones that I've seen on thumb drives.

That takes a fair amount of force. Enough to damage both plug and socket.

Hmmm... Some receiving devices short the 2 data pins together, some use resistors of various values between the data pins to request more current, and these schemes aren't compatible with each other, nor do they all result in the same current delivery. Some even negotiate with a standard computer mounted USB socket using a data packet to ask for more current, so they can only draw the default current from a normal charger.

Finally. Until USB3 takes over.

Incidentally, I recently bought a Nokia phone that will charge either from the latest standard Nokia round plug type charger in an hour or so, or via Micro USB in two or three hours.