Risking it all on a Poundland Purchase.

[P Jameson]

Poundland are doing a little cable with USB at one end and five connections
the other end to connect to a variety of different Smart Phones. So you can
charge your phone from your laptop.

Would the voltage likely be *steady* enough not to damage the phone with
'spikes' ?

They also do an adapter to plug into the car cigarette socket with a USB
femail socket built in. This will then accomodate the first mentioned lead.

Would the cigarette socket also be likely to 'spike' and damage the phone?

(dont ask how much they are).

[Brian Gaff]

Well if they were dangerous, they should come with a warning, but if they
start blowing up phones, even at the price you would probably have a claim
against the shop if there was no warning.
Brian

--
From the Bed of Brian Gaff.
The email is valid as bri...@blueyonder.co.uk
Blind user.
"P Jameson" <58214...@mail.invalid> wrote in message
news:lk890l$3h8$1...@dont-email.me...

[Andy Burns]

P Jameson wrote:

> Poundland are doing a little cable with USB at one end and five connections
> the other end to connect to a variety of different Smart Phones. So you can
> charge your phone from your laptop.

USB ports on laptops generally only provide 0.5A, divide that 0.5A
between five devices and it wouldn't go far, so presumably it has five
different types of connector and you pick the one that fits the phone?

Modern phones will take up to 1 or 2A, so charging will be slow, some
phones won't stoop that low and will refuse to charge at all.

> Would the voltage likely be *steady* enough not to damage the phone with
> 'spikes' ?

Provided the phone wants 5V (which is what USB provides) the supply is
regulated for the innards of the laptop anyway.

> They also do an adapter to plug into the car cigarette socket with a USB
> femail socket built in. This will then accomodate the first mentioned lead.
>
> Would the cigarette socket also be likely to 'spike' and damage the phone?

No, it'll be regulated from the car's nominal 12v down to 5V.

[Martin Bonner]

On Monday, May 5, 2014 3:59:14 PM UTC+1, P Jameson wrote:
> Poundland are doing a little cable with USB at one end and five connections
> the other end to connect to a variety of different Smart Phones. So you can
> charge your phone from your laptop.
>
> Would the voltage likely be *steady* enough not to damage the phone with
> 'spikes' ?

The laptop would be damaged by voltage spikes too - so yes.

>
> They also do an adapter to plug into the car cigarette socket with a USB
> femail socket built in. This will then accomodate the first mentioned lead.
>
> Would the cigarette socket also be likely to 'spike' and damage the phone?

I doubt it, but this is *slightly* more dodgy. It depends on your car
electrics. High quality adaptors would have plenty of smoothing to remove
any spikes.

> (dont ask how much they are).

... but you probably don't get high quality for £1

[Jabba]

P Jameson scribbled...

There's not enough power for them to work on many laptops. I've had one
connected to my pc for a couple of years, never had a problem with it.

[Gazz]

"Martin Bonner" <martin...@yahoo.co.uk> wrote in message
news:8fb90637-0241-4ff6...@googlegroups.com...

i had a cheap garmin usb car charger let it's magic smoke out once.... the
second day of use in my new car (both the charger and the car)
Not a nice thing to happen as your driving, luckily we were in town, but got
some funny looks when a smoking charger was chucked out the window into the
gutter,

i then got one of those tomtom branded fag lighter extensions with 2 usb
sockets on the side, one usb socket is a 1 or 1.5 amp 'fast charge' socket,
and it allows me to plug in the charger for the brodit phone mount due to
the fag lighter socket pass through.

but for those cable jobbies with a USB A socket on one end, and a selection
of mini, micro and those awkward bastard phones that still use proprietry
charging jacks, they usually have no electronics in them at all, so it'll be
upto the devise providing the power to keep to the usb voltage and current
standard,

[meow...@care2.com]

On Monday, May 5, 2014 3:59:14 PM UTC+1, P Jameson wrote:

> Poundland are doing a little cable with USB at one end and five connections
> the other end to connect to a variety of different Smart Phones. So you can
> charge your phone from your laptop.
> Would the voltage likely be *steady* enough not to damage the phone with
> 'spikes' ?

never a problem

> They also do an adapter to plug into the car cigarette socket with a USB
> femail socket built in. This will then accomodate the first mentioned lead.
> Would the cigarette socket also be likely to 'spike' and damage the phone?
> (dont ask how much they are).

this is less certain. There are electronics out there that dont survive or protect against the transients that are sommomnish in vehicles. I've no idea about poundland's specs.


NT

[Ian Field]

"P Jameson" <58214...@mail.invalid> wrote in message
news:lk890l$3h8$1...@dont-email.me...

The multi-connector is just a splitter - if you get any spikes, they're
coming from the laptop.

The specification is pretty tight: 5V @ 500mA - reasonable to assume you can
only charge one gadget ar a time.

The car adaptor obviously has some kind of voltage regulator to drop the 12V
down to 5V - at �1 you can afford to break one open and describe to us
what's in it so we can give better informed advice about any potential risk.

[Peter Duncanson]

On Mon, 5 May 2014 15:59:14 +0100, "P Jameson" <58214...@mail.invalid>
wrote:

>Poundland are doing a little cable with USB at one end and five connections
>the other end to connect to a variety of different Smart Phones. So you can
>charge your phone from your laptop.
>
>Would the voltage likely be *steady* enough not to damage the phone with
>'spikes' ?
>

I have no personal experience of this, however....

Charging a Smartphone from a USB socket on a PC or Mac is completely
normal. There should be no voltage spikes as the power output from the
USB socket is designed to power external devices. The real question here
is whether a single USB socket can supply enough current to charge five
Smartphones at once in a reasonable time.

>They also do an adapter to plug into the car cigarette socket with a USB
>femail socket built in. This will then accomodate the first mentioned lead.
>
>Would the cigarette socket also be likely to 'spike' and damage the phone?
>

No. The adapter will contain electronics to reduce the voltage to what
is needed by the phone and will regulate it.

The cigarette lighter socket plug on the connector for charging my
non-smart Nokia mobile has on the label:

Inoput: DC 12V/24V
Output: 5.7V 800 mA

The mains adpater for charging that phone has an output of 5.3V DC.

--
Peter Duncanson
(in uk.tech.digital-tv)

[Roger Mills]

On 05/05/2014 15:59, P Jameson wrote:
> Poundland are doing a little cable with USB at one end and five connections
> the other end to connect to a variety of different Smart Phones. So you can
> charge your phone from your laptop.
>
> Would the voltage likely be *steady* enough not to damage the phone with
> 'spikes' ?
>

It's only a dumb cable - the voltage comes from the laptop. The laptop's
USB output should be regulated to 5v - so it won't damage the phone.
Just mightn't charge it as fast as a dedicated charger 'cos the laptop's
USB will likely only supply 500mA.

> They also do an adapter to plug into the car cigarette socket with a USB
> femail socket built in. This will then accomodate the first mentioned lead.
>
> Would the cigarette socket also be likely to 'spike' and damage the phone?
>

No, it will be a regulated DC to DC converter to produce 5v from the
car's 12+ volts. Very likely the same innards as those sold by the likes
of Maplin at several times the price.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

[Ian Field]

"Peter Duncanson" <ma...@peterduncanson.net> wrote in message
news:j1ffm91mtjpci6cb3...@4ax.com...

> On Mon, 5 May 2014 15:59:14 +0100, "P Jameson" <58214...@mail.invalid>
> wrote:
>
>>Poundland are doing a little cable with USB at one end and five
>>connections
>>the other end to connect to a variety of different Smart Phones. So you
>>can
>>charge your phone from your laptop.
>>
>>Would the voltage likely be *steady* enough not to damage the phone with
>>'spikes' ?
>>
> I have no personal experience of this, however....
>
> Charging a Smartphone from a USB socket on a PC or Mac is completely
> normal. There should be no voltage spikes as the power output from the
> USB socket is designed to power external devices. The real question here
> is whether a single USB socket can supply enough current to charge five
> Smartphones at once in a reasonable time.
>
>>They also do an adapter to plug into the car cigarette socket with a USB
>>femail socket built in. This will then accomodate the first mentioned
>>lead.
>>
>>Would the cigarette socket also be likely to 'spike' and damage the phone?
>>
> No. The adapter will contain electronics to reduce the voltage to what
> is needed by the phone and will regulate it.

I think the point is whether a �1 charge adapter is safe to use on say; a
�100 smartphone for instance.

If it uses a series pass transistor in the regulator, there's always a
possibility the transistor could fail short-circuit and dump the full 12V on
the USB connector.

If the target device uses a lithium battery, a fault condition of 12V on the
USB connector could overwhelm the charge control chip and cause
overcharging - overcharged lithium cells tend to get thermal runaway and
vent with flaming gas!

How many corners did they cut to get it on the shelves at that price?!

[alan]

On 05/05/2014 16:15, Martin Bonner wrote:

> High quality adaptors would have plenty of smoothing to remove
> any spikes.

They probably do not. Some of the "quality" branded 12V/5V adapters for
the car are so small there is no room for anything large.

It will be a switched mode converter using a commonly available chip
that cost pence.

As already stated the current available from a USB lead connected to a
computer/laptop will be limited and the capability will be charging one
phone at a time. Even from a 12V/5V converter for the car probably it
will be limited to charging only one or two devices at the same time.


--
mailto:news{at}admac(dot}myzen{dot}co{dot}uk

[tim.....]

"P Jameson" <58214...@mail.invalid> wrote in message
news:lk890l$3h8$1...@dont-email.me...

> Poundland are doing a little cable with USB at one end and five
> connections the other end to connect to a variety of different Smart
> Phones. So you can charge your phone from your laptop.

I bought a poundland (actually it was a 99p shop) USB hub

it was CFU

tim

[Scott]

On Mon, 05 May 2014 17:50:22 +0100, Peter Duncanson
<ma...@peterduncanson.net> wrote:

>On Mon, 5 May 2014 15:59:14 +0100, "P Jameson" <58214...@mail.invalid>
>wrote:
>
>>Poundland are doing a little cable with USB at one end and five connections
>>the other end to connect to a variety of different Smart Phones. So you can
>>charge your phone from your laptop.
>>
>>Would the voltage likely be *steady* enough not to damage the phone with
>>'spikes' ?
>>
>I have no personal experience of this, however....
>
>Charging a Smartphone from a USB socket on a PC or Mac is completely
>normal. There should be no voltage spikes as the power output from the
>USB socket is designed to power external devices. The real question here
>is whether a single USB socket can supply enough current to charge five
>Smartphones at once in a reasonable time.

I suspect that is not its intended purpose. As another poster has
commented, it is more likely to be designed to allow connectivity with
different devices.

>
>>They also do an adapter to plug into the car cigarette socket with a USB
>>femail socket built in. This will then accomodate the first mentioned lead.
>>
>>Would the cigarette socket also be likely to 'spike' and damage the phone?
>>
>No. The adapter will contain electronics to reduce the voltage to what
>is needed by the phone and will regulate it.

I'm sure that's true but I think the point of the question is whether
a device that costs �1 will be up to the job.

[Scott]

On Mon, 05 May 2014 17:52:43 +0100, Roger Mills <watt....@gmail.com>
wrote:

[snip]

>
>No, it will be a regulated DC to DC converter to produce 5v from the
>car's 12+ volts. Very likely the same innards as those sold by the likes
>of Maplin at several times the price.

I think you have analysed the question correctly but not extended this
analysis into your answer :-)

[Graham.]

I bought a USB SD card reader from Pound World but it failed after a
few weeks. I bought another one but that failed too.
I think if you plug and unplug the whole thing from the computer it is
OK but it doesn't like the card being inserted or removed when the
reader is powered.

CBA buying another one to investigate further.

--

Graham.

%Profound_observation%

[Adrian C]

On 05/05/14 15:59, P Jameson wrote:
> Poundland are doing a little cable with USB at one end and five connections
> the other end to connect to a variety of different Smart Phones. So you can
> charge your phone from your laptop.
>

Had a look a couple of weeks ago, they also sell USB phone chargers that
plug into the mains. Of course these are safe. Only a quid.



So I spent a while in the shop thinking I'd buy one to take to bits out
of morbid curiosity, but then I spotted a bag of 'spicy crackers' that
probably rates higher in the morbidity for a pound sweepstake. So I
bought that...



Hmmm, WiFi doesn't permeate too well here 6 feet down. Am I getting out?


--
Not Me

[Rod Speed]

P Jameson <58214...@mail.invalid> wrote

> Poundland are doing a little cable with USB at one end and five
> connections the other end to connect to a variety of different Smart
> Phones. So you can charge your phone from your laptop.

> Would the voltage likely be *steady* enough not to damage the phone with
> 'spikes' ?

Yes. The voltage is determined by the laptop, not that cable thing.

The very fundamental problem tho is that there are a variety of
ways those things signal how much current they need so its not
very likely that an el cheapo cable thing will be able to do that
correctly with all the phone connectors, so it wont necessarily
charge the phone as quickly as possible, or at all in the worst cases.

> They also do an adapter to plug into the car cigarette socket with a USB
> femail socket built in. This will then accomodate the first mentioned
> lead.

> Would the cigarette socket also be likely to 'spike' and damage the phone?

That�s certainly much more likely.

[Ian Field]

"Adrian C" <em...@here.invalid> wrote in message
news:bsq1mq...@mid.individual.net...

> On 05/05/14 15:59, P Jameson wrote:
>> Poundland are doing a little cable with USB at one end and five
>> connections
>> the other end to connect to a variety of different Smart Phones. So you
>> can
>> charge your phone from your laptop.
>>
>
> Had a look a couple of weeks ago, they also sell USB phone chargers that
> plug into the mains. Of course these are safe. Only a quid.
>
>
>
> So I spent a while in the shop thinking I'd buy one to take to bits out of
> morbid curiosity,

There's various gadgets in Poundland that I'd like to pull apart out of
curiosity - but all those �'s mount up.

[Ian Field]

"Rod Speed" <rod.sp...@gmail.com> wrote in message
news:bsq6c8...@mid.individual.net...

> P Jameson <58214...@mail.invalid> wrote
>
>> Poundland are doing a little cable with USB at one end and five
>> connections the other end to connect to a variety of different Smart
>> Phones. So you can charge your phone from your laptop.
>
>> Would the voltage likely be *steady* enough not to damage the phone with
>> 'spikes' ?
>
> Yes. The voltage is determined by the laptop, not that cable thing.
>
> The very fundamental problem tho is that there are a variety of
> ways those things signal how much current they need

In the original USB specification it was 100mA unless the target device
signalled otherwise, then a max 500mA was available.

AFAIK that has largely been dropped and the full 500mA is usually available
by default.

A common scheme is "Polyfuse" protection - its a PTC thermistor that can
heat up with the current flowing through it, at a certain current it heats
enough to increase in resistance enough to practically stop current flow.

When the overload is removed it cools and returns to low resistance, so its
self resetting.

[charles]

In article <hAR9v.201663$iZ5....@fx17.am4>, Ian Field

That could well explain why my "Nokia Smart Phone" refused to charge from a
cheap car USB adaptor.

--
From KT24

Using a RISC OS computer running v5.18

[Ian Field]

"charles" <cha...@charleshope.demon.co.uk> wrote in message
news:54033022...@charleshope.demon.co.uk...

In any computer, the 5V rail the USB supply comes from is capable of at
least several amps, without short circuit protection, a mishap could result
in melted copper tracks on the motherboard.

The arrangement in a car adapter is a little different - and there's various
ways of going about it depending how cheap they want to make it.

Possibly the best way is with a switch-mode chip like the industry standard
MC34063 - whether you'll get that for a � is another matter.

Next time I go into town, I might punt a � for one just to break open and
see what's in it.

[Rod Speed]

Ian Field <gangprob...@ntlworld.com> wrote
> Rod Speed <rod.sp...@gmail.com> wrote

>> P Jameson <58214...@mail.invalid> wrote

>>> Poundland are doing a little cable with USB at one end and five
>>> connections the other end to connect to a variety of different Smart
>>> Phones. So you can charge your phone from your laptop.

>>> Would the voltage likely be *steady* enough not to damage the phone with
>>> 'spikes' ?

>> Yes. The voltage is determined by the laptop, not that cable thing.

>> The very fundamental problem tho is that there are a variety of ways
>> those things signal how much current they need

> In the original USB specification it was 100mA unless the target device
> signalled otherwise, then a max 500mA was available.

> AFAIK that has largely been dropped and the full 500mA is usually
> available by default.

That�s a different issue to the current situation where plenty of
phones will happily charge at a lot higher current than 500mA
when that current is available. That would be particularly relevant
with the car fag adapter rather than the use on the laptop. It
is obviously very desirable to have the phone charge as quickly
as possible, particularly when you are charging it in the car after
you have discovered that you forgot to charge it overnight etc.

And needless to say, there are a variety of ways various phones
use to signal that they are can charge at the multiple amps rates.

> A common scheme is "Polyfuse" protection - its a PTC thermistor that can
> heat up with the current flowing through it, at a certain current it heats
> enough to increase in resistance enough to practically stop current flow.

> When the overload is removed it cools and returns to low resistance, so
> its self resetting.

Just had a technoklutz manage to trigger the protection
in a Toshiba laptop USB port by shoving a 3.5mm jack in
there without looking at where he was putting the jack.

In that case it was actually a laptop reboot that reset
the USB port. I haven't managed to remember to get
the model number from him to check what the Toshiba
maintenance manual actually says about that.

[Rod Speed]

charles <cha...@charleshope.demon.co.uk> wrote

> Ian Field <gangprob...@ntlworld.com> wrote
>> Rod Speed <rod.sp...@gmail.com> wrote

>>> P Jameson <58214...@mail.invalid> wrote

>>>> Poundland are doing a little cable with USB at one end and five
>>>> connections the other end to connect to a variety of different
>>>> Smart Phones. So you can charge your phone from your laptop.

>>>> Would the voltage likely be *steady* enough not to damage the phone
>>>> with 'spikes' ?

>>> Yes. The voltage is determined by the laptop, not that cable thing.

>>> The very fundamental problem tho is that there are a variety
>>> of ways those things signal how much current they need

>> In the original USB specification it was 100mA unless the target
>> device signalled otherwise, then a max 500mA was available.

>> AFAIK that has largely been dropped and the
>> full 500mA is usually available by default.

>> A common scheme is "Polyfuse" protection - its a PTC thermistor
>> that can heat up with the current flowing through it, at a certain
>> current it heats enough to increase in resistance enough to
>> practically stop current flow.

>> When the overload is removed it cools and
>> returns to low resistance, so its self resetting.

> That could well explain why my "Nokia Smart Phone"
> refused to charge from a cheap car USB adaptor.

No, that is due to what I said previously. The various smartphones
use different ways of signalling that they can charge with more
than 500mA and some of them just refuse to charge at all if they
don�t see the signal from the USB that they are looking for.

The signalling is done by different fixed voltage
levels etc on the USB data lines in that connector.

[Ian Field]

"Rod Speed" <rod.sp...@gmail.com> wrote in message

news:bsq9i4...@mid.individual.net...

> Ian Field <gangprob...@ntlworld.com> wrote
>> Rod Speed <rod.sp...@gmail.com> wrote
>>> P Jameson <58214...@mail.invalid> wrote
>
>>>> Poundland are doing a little cable with USB at one end and five
>>>> connections the other end to connect to a variety of different Smart
>>>> Phones. So you can charge your phone from your laptop.
>
>>>> Would the voltage likely be *steady* enough not to damage the phone
>>>> with 'spikes' ?
>
>>> Yes. The voltage is determined by the laptop, not that cable thing.
>
>>> The very fundamental problem tho is that there are a variety of ways
>>> those things signal how much current they need
>
>> In the original USB specification it was 100mA unless the target device
>> signalled otherwise, then a max 500mA was available.
>
>> AFAIK that has largely been dropped and the full 500mA is usually
>> available by default.
>
> That�s a different issue to the current situation where plenty of
> phones will happily charge at a lot higher current than 500mA
> when that current is available. That would be particularly relevant
> with the car fag adapter

That's part of what the OP was asking, a badly designed/cheap car adapter
might waste an awful lot of power as heat - an still not quite make the
500mA spec.

A very cheaply made linear regulator could suffer excessive heating at full
load - if the series pass transistor fails, it will fail short-circuit and
dump the full 12V on the load.

A step down switch mode regulator will be a buck-regulator - which also has
a series transistor which will dump the full 12V if it fails, but the
transistor generates much less heat and is far less likely to fail.

Regulation is usually a lot more accurate with a switcher too.

[NY]

"Ian Field" <gangprob...@ntlworld.com> wrote in message
news:JpS9v.165938$Y24....@fx03.am4...

>> That�s a different issue to the current situation where plenty of
>> phones will happily charge at a lot higher current than 500mA
>> when that current is available. That would be particularly relevant
>> with the car fag adapter

Do car 12V -> 5V adaptors have an over-current cutout which will cut the
power to the phone if it tries to draw too much current? My wife has a
tablet PC which will charge happily from some car chargers but not others.
Even in the latter case, it still gives a "charging" indication, rather than
reporting that the charger has been disconnected, but the battery charge
never increases (indeed it falls gradually if the tablet is turned on). The
chargers that fail to charge it still charge other devices OK.

I could understand an over-current cutout, but I'm puzzled that if it comes
into effect the device doesn't report that charging has stopped.

[Ian Field]

"NY" <m...@privacy.net> wrote in message
news:xJednVuARd58a_rO...@brightview.co.uk...

> "Ian Field" <gangprob...@ntlworld.com> wrote in message
> news:JpS9v.165938$Y24....@fx03.am4...
>>> That�s a different issue to the current situation where plenty of
>>> phones will happily charge at a lot higher current than 500mA
>>> when that current is available. That would be particularly relevant
>>> with the car fag adapter
>
> Do car 12V -> 5V adaptors have an over-current cutout which will cut the
> power to the phone if it tries to draw too much current?

That question goes to the root of what the OP asked - it all depends what
you get for your � in Poundland.

A common switch mode regulator chip used in this type of application is the
MC34063 - it has a pin to include a current sensing resistor, whether the
manufacturer of the adapter bothered to use it is another matter.

[Johny B Good]

Not just any computer MoBo, only PC Chips MoBos ime. Even here they
do add a safety fuse in the form of either a very thin circuit trace
or an smd inductor, not items you'd normally class as a fuse but, at 5
volts, good enough to stop a conflagration.

However, the downside of this one shot fusing protection is that all
the USB and PS/2 sockets lose their 5v rail (keyboard and mouse stop
working). I should know 'cos I've bridged a few burnt out
inductors/cct traces with a 3 amp polyfuse on these shite MoBos (after
clearing the short cicrcuit, usually a vandalisedd USB socket from
which I've snipped the offending pin).

With every other brand of MoBo I've seen, the standard practice is to
completely forego the USB negotiation for current protocols and simply
wire the +5v pins to a common bus protected by a 3 or 4 amp polyfuse.
IOW, your 2 or 3 amp usb charger is unlikely to be kept short of juice
when plugged into a desktop PC.

A laptop, otoh, probably does include the full power control protocol
to minimise excessive demand from its battery (but, even here, this
may not always be the case).

>
>The arrangement in a car adapter is a little different - and there's various
>ways of going about it depending how cheap they want to make it.
>
>Possibly the best way is with a switch-mode chip like the industry standard
>MC34063 - whether you'll get that for a � is another matter.
>
>Next time I go into town, I might punt a � for one just to break open and
>see what's in it.

With a limit of just half an amp output, the chinese manufacturer
will be able to get away with mounting the chip straight onto the
circuit board with a blob of protective epoxy to stick it down to the
board (just like those cheap USB flash memory card adapters).

They only have to survive 6 to 12 months before atmospheric pollution
poisons the chip and the punter has to...well, punt another quid their
way. Most Pound shop customers wouldn't bother invoking SOGA over a
one pound item. The Pound shop management rely on this factor but
aren't stupid enough to open this can of worms so will cheerfully
accept any warranty returns with good grace.

If the chip turns out to be under a blob of epoxy on the circuit
board, I'd be a little leary of such a product in this case.
--
Regards, J B Good

[Rod Speed]

Ian Field <gangprob...@ntlworld.com> wrote
> Rod Speed <rod.sp...@gmail.com> wrote
>> Ian Field <gangprob...@ntlworld.com> wrote
>>> Rod Speed <rod.sp...@gmail.com> wrote
>>>> P Jameson <58214...@mail.invalid> wrote

>>>>> Poundland are doing a little cable with USB at one end and five
>>>>> connections the other end to connect to a variety of different Smart
>>>>> Phones. So you can charge your phone from your laptop.

>>>>> Would the voltage likely be *steady* enough not to damage the phone
>>>>> with 'spikes' ?

>>>> Yes. The voltage is determined by the laptop, not that cable thing.

>>>> The very fundamental problem tho is that there are a variety of ways
>>>> those things signal how much current they need

>>> In the original USB specification it was 100mA unless the target device
>>> signalled otherwise, then a max 500mA was available.

>>> AFAIK that has largely been dropped and the full 500mA is usually
>>> available by default.

>> That�s a different issue to the current situation where plenty of phones
>> will happily charge at a lot higher current than 500mA when that current
>> is available. That would be particularly relevant with the car fag
>> adapter

> That's part of what the OP was asking,

No.

> a badly designed/cheap car adapter might waste an awful lot of power as
> heat - an still not quite make the 500mA spec.

That cheap cable will be entirely passive, just a splitter
and maybe some attempt to signal what the cable can
deliver current wise to the smartphones, but the problem
is that the signalling methods that are used don�t allow
any way for them all to signal properly without some
form of switching which I bet it doesn�t have.

There won't be any waste as heat with the cable and
there is very unlikely to be with the fag plug charger
either, just because its not even possible to get rid
of enough heat in one of those and cheaper to use
a switcher anyway.

> A very cheaply made linear regulator could suffer excessive heating at
> full load

But there is no way to get rid of that heat in a
fag plug adapter, so a switcher would be used
instead and that would be cheaper anyway.

> - if the series pass transistor fails, it will fail short-circuit and dump
> the full 12V on the load.

But the smartphone may be designed to handle that situation.

> A step down switch mode regulator will be a buck-regulator - which also
> has a series transistor which will dump the full 12V if it fails, but the
> transistor generates much less heat and is far less likely to fail.

> Regulation is usually a lot more accurate with a switcher too.

The real problem isnt how it fails, the real problem
is the way the different smartphones signal that they
can use more current and with most of them refusing
to charge at all when they don�t see the type of
signalling they expect to see. They do that
because they choose to fail safe in that situation.

[Rod Speed]

NY <m...@privacy.net> wrote
> Rod Speed wrote

>> That�s a different issue to the current situation where plenty of
>> phones will happily charge at a lot higher current than 500mA
>> when that current is available. That would be particularly relevant
>> with the car fag adapter

> Do car 12V -> 5V adaptors have an over-current cutout which will cut the
> power to the phone if it tries to draw too much current?

The best of them do, but its far from clear what those very cheap ones do on
that.

Presumably if the ic used has that capability, the better designs
would use that, but there must be some of the most incompetent
designers that don�t even bother to implement that even when
the ic can do it without any added cost.

> My wife has a tablet PC which will charge happily from some car chargers
> but not others.

And that is because there is more than one way to
signal that it can use the higher charging currents fine.

> Even in the latter case, it still gives a "charging" indication, rather
> than reporting that the charger has been disconnected,

That varys with the tablet and smartphone. Some of the better
designs do indicate when they are refusing to charge even when
the 5V is available.

> but the battery charge never increases (indeed it falls gradually if the
> tablet is turned on).

Yeah, that's not uncommon, because of the different signalling methods used.

> The chargers that fail to charge it still charge other devices OK.

Because they use a different signalling detail to the one that refuses to
charge.

> I could understand an over-current cutout, but I'm puzzled that if it
> comes into effect the device doesn't report that charging has stopped.

It doesn�t because that isnt a cutout. It doesn�t cut out, so
the 5V is still there and so the charging indication is still there.

The signalling is there so the charger can decide that its not a fault
in what is being charged, its just using amps to charge quicker.

[Johny B Good]

On Mon, 05 May 2014 18:35:03 +0100, Graham. <m...@privicy.net> wrote:

>On Mon, 5 May 2014 19:11:19 +0200, "tim....."
><tims_n...@yahoo.co.uk> wrote:
>
>>
>>
>>"P Jameson" <58214...@mail.invalid> wrote in message
>>news:lk890l$3h8$1...@dont-email.me...
>>> Poundland are doing a little cable with USB at one end and five
>>> connections the other end to connect to a variety of different Smart
>>> Phones. So you can charge your phone from your laptop.
>>
>>I bought a poundland (actually it was a 99p shop) USB hub
>>
>>it was CFU
>>
>>tim
>>
>
>I bought a USB SD card reader from Pound World but it failed after a
>few weeks. I bought another one but that failed too.
>I think if you plug and unplug the whole thing from the computer it is
>OK but it doesn't like the card being inserted or removed when the
>reader is powered.

That's not a card reader, it's a flash to USB pen drive converter.
The idea is that you load an appropriate memory card into the slot
then plug it in. When it comes to ejecting it, you have to treat the
whole thing the same as you would a usb pen drive, that is, you use
the 'safely eject hardware' applet in the systray before unplugging it
from the USB slot.

[Brian Gaff]

Yes, but if my life depended on an item I'd certainly not buy it from a
pound shop. Luckily none of them sell parachutes..... yet.
Brian

--
From the Sofa of Brian Gaff Reply address is active

"Rod Speed" <rod.sp...@gmail.com> wrote in message

news:bsqf0u...@mid.individual.net...

> Ian Field <gangprob...@ntlworld.com> wrote
>> Rod Speed <rod.sp...@gmail.com> wrote
>>> Ian Field <gangprob...@ntlworld.com> wrote
>>>> Rod Speed <rod.sp...@gmail.com> wrote
>>>>> P Jameson <58214...@mail.invalid> wrote
>
>>>>>> Poundland are doing a little cable with USB at one end and five
>>>>>> connections the other end to connect to a variety of different Smart
>>>>>> Phones. So you can charge your phone from your laptop.
>
>>>>>> Would the voltage likely be *steady* enough not to damage the phone
>>>>>> with 'spikes' ?
>
>>>>> Yes. The voltage is determined by the laptop, not that cable thing.
>
>>>>> The very fundamental problem tho is that there are a variety of ways
>>>>> those things signal how much current they need
>
>>>> In the original USB specification it was 100mA unless the target device
>>>> signalled otherwise, then a max 500mA was available.
>
>>>> AFAIK that has largely been dropped and the full 500mA is usually
>>>> available by default.
>

>>> That�s a different issue to the current situation where plenty of phones

>>> will happily charge at a lot higher current than 500mA when that current
>>> is available. That would be particularly relevant with the car fag
>>> adapter
>
>> That's part of what the OP was asking,
>
> No.
>
>> a badly designed/cheap car adapter might waste an awful lot of power as
>> heat - an still not quite make the 500mA spec.
>
> That cheap cable will be entirely passive, just a splitter
> and maybe some attempt to signal what the cable can
> deliver current wise to the smartphones, but the problem

> is that the signalling methods that are used don�t allow

> any way for them all to signal properly without some

> form of switching which I bet it doesn�t have.

>
> There won't be any waste as heat with the cable and
> there is very unlikely to be with the fag plug charger
> either, just because its not even possible to get rid
> of enough heat in one of those and cheaper to use
> a switcher anyway.
>
>> A very cheaply made linear regulator could suffer excessive heating at
>> full load
>
> But there is no way to get rid of that heat in a
> fag plug adapter, so a switcher would be used
> instead and that would be cheaper anyway.
>
>> - if the series pass transistor fails, it will fail short-circuit and
>> dump the full 12V on the load.
>
> But the smartphone may be designed to handle that situation.
>
>> A step down switch mode regulator will be a buck-regulator - which also
>> has a series transistor which will dump the full 12V if it fails, but the
>> transistor generates much less heat and is far less likely to fail.
>
>> Regulation is usually a lot more accurate with a switcher too.
>
> The real problem isnt how it fails, the real problem
> is the way the different smartphones signal that they
> can use more current and with most of them refusing

> to charge at all when they don�t see the type of

[dennis@home]

On 05/05/2014 21:07, Ian Field wrote:

> In any computer, the 5V rail the USB supply comes from is capable of at
> least several amps, without short circuit protection, a mishap could
> result in melted copper tracks on the motherboard.

In any computer with proper USB you can short it out for as long as you
like and nothing will break. The USB chips include such protection and
even power management so the OS can limit the power being drawn.

If you are silly enough to wire a USB header to the 5V power rail there
will be a big bang and things will melt when shorted. (seen that done)

[dennis@home]

On 05/05/2014 22:42, Johny B Good wrote:

> With a limit of just half an amp output, the chinese manufacturer
> will be able to get away with mounting the chip straight onto the
> circuit board with a blob of protective epoxy to stick it down to the
> board (just like those cheap USB flash memory card adapters).

There are good reasons why some electronics are like that.. its more
reliable and is used in telecoms and military applications.
Its only a problem if its done incorrectly.

[whisky-dave]

On Monday, 5 May 2014 15:59:14 UTC+1, P Jameson wrote:
> Poundland are doing a little cable with USB at one end and five connections

> (dont ask how much they are).

I'm not going get ripped off by poundland I'm waiting till the 99p shop gets them in :)

[Graham.]

Now you tell me! ;-)



--

Graham.

%Profound_observation%

[Ian Field]

"Johny B Good" <johnny...@invalid.ntlworld.com> wrote in message
news:n17gm9drfc9m70jke...@4ax.com...

I've bought multi-card readers from various suppliers and paid considerably
more than �1 for them - without exception, any camera has refused to
recognise a card formatted by one of these card readers.

[Ian Field]

"Johny B Good" <johnny...@invalid.ntlworld.com> wrote in message

news:navfm9tf7g4982uhr...@4ax.com...

You'll probably find an increasing number of MOBOs have a polyfuse from the
outset.

[Ian Field]

"dennis@home" <den...@killspam.kicks-ass.net> wrote in message
news:5368bd78$0$51138$c3e8da3$28e7...@news.astraweb.com...

> On 05/05/2014 21:07, Ian Field wrote:
>
>> In any computer, the 5V rail the USB supply comes from is capable of at
>> least several amps, without short circuit protection, a mishap could
>> result in melted copper tracks on the motherboard.
>
> In any computer with proper USB you can short it out for as long as you
> like and nothing will break. The USB chips include such protection and
> even power management so the OS can limit the power being drawn.

AFAIK - available current negotiation is falling by the wayside - nowadays
many just give you 500mA by default and use a polyfuse for protection.

[Ian Field]

"Rod Speed" <rod.sp...@gmail.com> wrote in message

news:bsqfut...@mid.individual.net...

> NY <m...@privacy.net> wrote
>> Rod Speed wrote
>
>>> That�s a different issue to the current situation where plenty of
>>> phones will happily charge at a lot higher current than 500mA
>>> when that current is available. That would be particularly relevant
>>> with the car fag adapter
>
>> Do car 12V -> 5V adaptors have an over-current cutout which will cut the
>> power to the phone if it tries to draw too much current?
>
> The best of them do, but its far from clear what those very cheap ones do
> on that.

Just been in Poundland - but they were out of stock.

Town center is off the beaten track for me, but eventually they might have
them in stock when I go there - by the time I get one to crack open and
investigate the innards, this thread will probably be long forgotten.

[Ian Field]

"Rod Speed" <rod.sp...@gmail.com> wrote in message

news:bsqf0u...@mid.individual.net...

You're on about the USB with multiple connector tails - I was on about the
step down regulator in the car cigarette socket adaptor.

[Ian Field]

"Brian Gaff" <brian...@gmail.com> wrote in message
news:lka2co$iag$1...@dont-email.me...

> Yes, but if my life depended on an item I'd certainly not buy it from a
> pound shop. Luckily none of them sell parachutes..... yet.
> Brian

Apparently there are several competing pound shops - and one recently tried
to steal the show by introducing �1 bra's

*****AVALANCHE!!!!!*****.

[Martin Brown]

Although you probably could eject the media from systray and then remove
the card it would be more fiddly to do so.

>
> I've bought multi-card readers from various suppliers and paid
> considerably more than �1 for them - without exception, any camera has
> refused to recognise a card formatted by one of these card readers.

That is more than likely due to Windows perverse default formatting
strategy being inconsistent with what the camera expects to see. Most
cameras require that a certain directory structure is present on their
formatted media and some are very fussy about the file system.

I had a nasty fault with my Pentax istD when new sD memory cards crossed
the 2GB to 4GB barrier. The camera formatted it OK recognised there was
space on the card and allowed continued shooting after the 2GB barrier
but failed to store any of them. A firmware update fixed it.


--
Regards,
Martin Brown

[John Williamson]

On 06/05/2014 17:08, Ian Field wrote:
>
>

That's because, while they are formatted in camera using FAT32 or ExFAT,
the cameras also want to see certain directories that they put on the
card while formatting it for use. Every camera type has a different name
for these directories, and a card formatted in a Fuji will not be
recognised as formatted by a Sony, and vice versa, although after a card
is formatted by both cameras, it will work equally well in both cameras,
as it has both sets of proprietary directories, and all the camera does
when formatting is check the FAT and add its oewn directories. The
exception is, IIRC, Canon, who use a non-standard SD format instead of
FAT, which makes their cards unreadable except by their software, even
out of the camera.

My JVC HD video camcorder puts about five directories on the card, and
it uses them for storing things like scratch files and metadata.

--
Tciao for Now!

John.

[Johny B Good]

Like you, I was non the wiser as to it being a flash memory to USB
pen drive converter when I bought it and assumed it was a card reader
where you can leave it plugged into the USB port and eject and insert
the media as per a card reader.

It took me a few tries before I was convinced it was simply a pen
drive where you could pre-load the flash memory card of your choice.

I think it was the parkable USB plug on a very short cable that had
confused me. The earlier version which just looked like an oversized
pen drive with an SD slot left no such room for confusion.

[Johny B Good]

That's news to me. I've got a couple of Canon stills cameras
(PowerShot A720IS and SX40HS) and both use FAT32 on the SD media.

The only problem I had was the 2GB media limitation on the card
reader in the PC which I sorted by upgrading to a newer card reader
that was compatable with 4GB and larger capacity cards.

The Acer laptop had a single SD slot built in which, unfortunately,
also had this 2GB limitation. Despite it seemingly not being a USB
device, the firmware update did nothing for this limitation so when me
and the missus went on a cruise a few years back when the A720 was a
newly purchased camera, I took a couple of Poundland USB pen drive SD
adapters which did support 4GB and larger cards.

That was also the only time I installed the camera crapware as a
hedge against both pen drive adapters failing during the trip so I
still had a means to siphon the photos off the 4GB SD cards via the
camera's USB port. Thankfully, the need to run the crapware never
arose.

BTW, there's really no point in bothering to format the media using a
PC before putting it back in the camera. The camera is quite capable
of doing its own format (full or quick) thus guaranteeing the required
directory structure anyway. Formatting the media in a PC won't do any
harm, it's just that you might as well let the camera 'initialise' the
card for you to remove all doubts about necessary directory
structures.

[Johny B Good]

On Tue, 6 May 2014 17:11:28 +0100, "Ian Field"

With the exception of PC Chips MoBos (and rebadged clones), thats
been the case, ime, with every other brand of MoBo from before USB was
thrust unwanted upon the industry by Intel's "Sneaky Tricks" dept (a
strategy to ginger up the demand for more powerful CPUs).

The polyfuse was initially fitted to protect against shorts on the 5v
pin in the PS/2 keyboard and mouse sockets (probably just a half or
one amp polyfuse).

When USB started to appear on MoBos, they simply powered the 5v pins
on the usb sockets and headers from the same fused supply rail on the
MoBo, uprating the polyfuse to a 3 or 4 amp one to cater for the
increased loading.

[Johny B Good]

As far as I can see, Desktop PC MoBos never bothered with negotiated
power protocols on the USB sockets. They simply fed the 5v from a 3 or
4 amp polyfuse or two, allowing unlimited current within the limit of
the polyfuse rating to be available to a usb device. Dishing out an
extra 15 to 20 watts to usb gadgets was never going to be an issue on
a PC with a 300 watt or higher rated mains PSU to take the strain.

I think the USB power protocol was only ever employed by laptop /
netbook MoBos on account of the more limited power budget available
for such luxuries along with being part of the power management
features typical of laptop / netbook usage.

[John Williamson]

Obviously I misrembered the make, then. It was a camera being used by
one of the teachers I was carrying on a tour round Europe, and the
camera crashed when they tried to overfill the card with video. That's
when I found that I couldn't even open the card on the computer using a
couple of different file recovery programs, and checking on the maker's
website mentioned that they use their own special formatting system.

I couldn't even download a copy of the required programme without giving
them the full guarantee registration details of the camera, so I
regtretfully handed the lot back to the client, recommending they buy a
new card, but keep the old one for an attempted download when they
either got home or to a dealer.

> BTW, there's really no point in bothering to format the media using a
> PC before putting it back in the camera. The camera is quite capable
> of doing its own format (full or quick) thus guaranteeing the required
> directory structure anyway. Formatting the media in a PC won't do any
> harm, it's just that you might as well let the camera 'initialise' the
> card for you to remove all doubts about necessary directory
> structures.
>

If I'm worried about confidentiality of the material on the card, I do a
full secure wipe and format on the PC, as most of the cameras I've used
only do a quick format on the card, and it's *amazing* how many pictures
you can recover afterwards. One friend was extremely happy that I'd
recovered some of his wedding pictures that he thought he'd lost after
reformatting the card many times since the failed upload attempt,
assuming all those pictures were lost for ever.

[Rod Speed]

"Ian Field" <gangprob...@ntlworld.com> wrote in message

news:bT7av.307720$lM4.1...@fx34.am4...

>
>
> "dennis@home" <den...@killspam.kicks-ass.net> wrote in message
> news:5368bd78$0$51138$c3e8da3$28e7...@news.astraweb.com...
>> On 05/05/2014 21:07, Ian Field wrote:
>>
>>> In any computer, the 5V rail the USB supply comes from is capable of at
>>> least several amps, without short circuit protection, a mishap could
>>> result in melted copper tracks on the motherboard.
>>
>> In any computer with proper USB you can short it out for as long as you
>> like and nothing will break. The USB chips include such protection and
>> even power management so the OS can limit the power being drawn.
>
> AFAIK - available current negotiation is falling by the wayside

No it isn't with smartphone and tablet chargers particularly.

> - nowadays many just give you 500mA by default and use a polyfuse for
> protection.

Its much more complicated than that with chargers.
http://en.wikipedia.org/wiki/Common_External_Power_Supply

[Rod Speed]

"Ian Field" <gangprob...@ntlworld.com> wrote in message

news:pZ7av.273393$Nz7....@fx27.am4...

No, I also covered the fag socket adapter.

> - I was on about the step down regulator in the car cigarette socket
> adaptor.

So was I on that heat question particularly.

[Ian Field]

"Rod Speed" <rod.sp...@gmail.com> wrote in message

news:bst1q7...@mid.individual.net...

If its a switch mode converter - there's very little heat - that's the whole
point of them.

The series pass transistor is either fully on or fully off - when its fully
on its maximum current but very little volt drop, when its fully off there's
all the voltage but only miniscule leakage current - either way; V*A=W ends
up being not very much.

[Rod Speed]

"Johny B Good" <johnny...@invalid.ntlworld.com> wrote in message

news:p5jim9pi8qsn3tdvm...@4ax.com...

> On Tue, 6 May 2014 17:14:00 +0100, "Ian Field"
> <gangprob...@ntlworld.com> wrote:
>
>>
>>
>>"dennis@home" <den...@killspam.kicks-ass.net> wrote in message
>>news:5368bd78$0$51138$c3e8da3$28e7...@news.astraweb.com...
>>> On 05/05/2014 21:07, Ian Field wrote:
>>>
>>>> In any computer, the 5V rail the USB supply comes from is capable of at
>>>> least several amps, without short circuit protection, a mishap could
>>>> result in melted copper tracks on the motherboard.
>>>
>>> In any computer with proper USB you can short it out for as long as you
>>> like and nothing will break. The USB chips include such protection and
>>> even power management so the OS can limit the power being drawn.
>>
>>AFAIK - available current negotiation is falling by the wayside - nowadays
>>many just give you 500mA by default and use a polyfuse for protection.

> As far as I can see, Desktop PC MoBos never bothered
> with negotiated power protocols on the USB sockets.

Some of them certainly did.

> They simply fed the 5v from a 3 or 4 amp polyfuse or
> two, allowing unlimited current within the limit of the
> polyfuse rating to be available to a usb device.

Some of them did rather more than that.

> Dishing out an extra 15 to 20 watts to usb gadgets
> was never going to be an issue on a PC with a 300
> watt or higher rated mains PSU to take the strain.

The problem was more complicated than that, deciding
when the device taking more than an amp was doing that
to charge the device rather than it being a short which
the USB supply should not supply because it was a short.

That was the reason for the negotiation in the first place.

> I think the USB power protocol was only
> ever employed by laptop / netbook MoBos

That is not correct.

> on account of the more limited power budget available
> for such luxuries along with being part of the power
> management features typical of laptop / netbook usage.

There is no point in NEGOTIATION for that.

Plenty of the higher current devices like USB powered
external hard drives had two USB connectors, so the
device could get enough current to power the device.

[Indy Jess John]

On 06/05/2014 22:08, Johny B Good wrote:

> I think the USB power protocol was only ever employed by laptop /
> netbook MoBos on account of the more limited power budget available
> for such luxuries along with being part of the power management
> features typical of laptop / netbook usage.

An interesting discovery about my Win7 Toshiba laptop came when I bought
a Canon LED Scanner, which is powered from the USB socket.

The instructions say that it is a USB2 scanner. The laptop has 2xUSB2
and 1xUSB3 sockets. The scanner wouldn't run when connected to a USB2
socket but works perfectly powered from the USB3 socket. Whether the
laptop is running from internal battery or from mains power made no
difference. There must be something different about the power
availability from the USB socket.

Jim

[Indy Jess John]

On 06/05/2014 17:32, Martin Brown wrote:

> That is more than likely due to Windows perverse default formatting
> strategy being inconsistent with what the camera expects to see. Most
> cameras require that a certain directory structure is present on their
> formatted media and some are very fussy about the file system.

My Panasonic camera doesn't just format, it puts two folders on the
card. One is where the photos go when I take them. The other contains
a file of binary data - I have no idea what it does. It is a pretty
safe bet that the camera firmware expects to find this folder structure
on any media used. Windows formatting wouldn't set it up like that.

Jim

[Rod Speed]

"Ian Field" <gangprob...@ntlworld.com> wrote in message

news:CAcav.176114$wa2.1...@fx05.am4...

And that is why I said that its very unlikely to be anything
else with the fag socket adapter, because there isnt any
easy way to get rid of heat there, and because that
approach is actually cheaper to do as well.

> The series pass transistor is either fully on or fully off - when its
> fully on its maximum current but very little volt drop, when its fully off
> there's all the voltage but only miniscule leakage current - either way;
> V*A=W ends up being not very much.

You were the one that mentioned heat, not me.

[Jim Lesurf]

In article <%yP9v.341541$Kq1.2...@fx07.am4>, Ian Field
<gangprob...@ntlworld.com> wrote:


> "Peter Duncanson" <ma...@peterduncanson.net> wrote in message
> news:j1ffm91mtjpci6cb3...@4ax.com...
> > On Mon, 5 May 2014 15:59:14 +0100, "P Jameson"

> >>
> > No. The adapter will contain electronics to reduce the voltage to what
> > is needed by the phone and will regulate it.

> I think the point is whether a �1 charge adapter is safe to use on say;
> a �100 smartphone for instance.

> If it uses a series pass transistor in the regulator, there's always a
> possibility the transistor could fail short-circuit and dump the full
> 12V on the USB connector.

> How many corners did they cut to get it on the shelves at that price?!

The discussion and low price bring to mind something I discovered years ago
in kit supplied by someone.

The kit required various 12V / 9V / 5V supplies for different items in the
box. The 'designer' <sic> supplied some of the 9V or 5V by adding series
resistors to the output from a 12V regulator.

The result was predictable. The voltages varied as the items drew currents
that weren't constant. Performance was awful. And in the end some of the -
very costly - items failed due to drawing a 'lower than assumed' current,
so experiencing high rail voltages.

Caveat emptor. 8-/

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

[dennis@home]

On 06/05/2014 22:12, John Williamson wrote:

> If I'm worried about confidentiality of the material on the card, I do a
> full secure wipe and format on the PC, as most of the cameras I've used
> only do a quick format on the card, and it's *amazing* how many pictures
> you can recover afterwards. One friend was extremely happy that I'd
> recovered some of his wedding pictures that he thought he'd lost after
> reformatting the card many times since the failed upload attempt,
> assuming all those pictures were lost for ever.
>

You can format the card hundreds of times, it won't erase the data
unless it wears one of the cells out and reallocates a "free" one.

[John Williamson]

A full format, in theory, should generate an empty FAT and zero all the
available cells. A quick format just generates an empty FAT.

Most cameras don't give you a choice, and often just check the card is
formatted, format it if necessary, and then add their directories,
leaving the rest of the file structure intact.

[Max Demian]

"Indy Jess John" <jimw...@OMITblueyonder.co.uk> wrote in message
news:u5dav.263786$vB1....@fx36.am4...

I think it's basically 100 mA or more if the device asks nicely* (up to 500
mA I think - or is it 1A?). Your laptop is just being stroppy. (Some devices
like external HDDs expect to be connected to two USB sockets to provide
enough power.)

* I don't know how this 'negotiation' works. What about things like USB mug
warmers?

--
Max Demian

[Steve Thackery]

Jim Lesurf wrote:

> The kit required various 12V / 9V / 5V supplies for different items
> in the box. The 'designer' <sic> supplied some of the 9V or 5V by
> adding series resistors to the output from a 12V regulator.

That is absolutely appalling!

--
SteveT

[Andrew Gabriel]

In article <I9P9v.410200$H82.3...@fx23.am4>,
"Ian Field" <gangprob...@ntlworld.com> writes:
>
> The car adaptor obviously has some kind of voltage regulator to drop the 12V
> down to 5V - at �1 you can afford to break one open and describe to us
> what's in it so we can give better informed advice about any potential risk.

I've broken many open, to pinch the small switched mode PSU out of them
to use for something else. I've never seen one with any protection against
the FET shorting (which would generate 12V output), but I've never had that
happen yet either.

You can get ones which supply 4.2A now, for 2 x 2.1A USB outputs.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

[Andrew Gabriel]

In article <lk890l$3h8$1...@dont-email.me>,

"P Jameson" <58214...@mail.invalid> writes:
> Poundland are doing a little cable with USB at one end and five connections
> the other end to connect to a variety of different Smart Phones. So you can
> charge your phone from your laptop.
>
> Would the voltage likely be *steady* enough not to damage the phone with
> 'spikes' ?
>

> They also do an adapter to plug into the car cigarette socket with a USB
> femail socket built in. This will then accomodate the first mentioned lead.
>
> Would the cigarette socket also be likely to 'spike' and damage the phone?
>
> (dont ask how much they are).

I've taken to carrying a few around in my laptop bag.
If I'm away at a meeting, there are always one or two people walking
around trying to borrow phone chargers (most commonly iphone users).

Also, they are a bit fragile. You don't need to yank very hard on the
cable for the conductors to break. I'm probably on the third one for
my own use in a couple of years.

The style that Poundland do does change periodically, but they usually
have at least one variety in stock.

[Rod Speed]

"Max Demian" <max_d...@bigfoot.com> wrote in message
news:bsucu7...@mid.individual.net...

That varys, particularly with the stuff being discussed,
the USB smartphone and tablet chargers.

> What about things like USB mug warmers?

Those are even cruder, but there is no reason why
they can't use the same signalling that the smartphone
and tablets do and get amps if they want it and the
USB port can provide that.

[Max Demian]

"Steve Thackery" <nob...@nowhere.com> wrote in message
news:__Odnbuwqe4nYvTO...@bt.com...

Many moons ago I bought a PSU 'kit' to supply 6v to the motor of a portable
tape recorder. It was advertised as supplying 6V, 9V or 12V at up to 1A. It
consisted of a 12V output transformer, a rectifier, a 12V Zener, a
multi-tapped dropper resister and some capacitors for smoothing.

It would really only supply 1A at 12V; the use of the dropper resistor meant
that it couldn't supply any other voltage with reasonable regulation - even
a tranny with a push-pull output wouldn't have worked.

--
Max Demian

[djc]

DCIM (Digital Camera Images) and DCF (Design Rule for Camera File
System) one of those 'standards' that is not quite a standard.

http://www.techterms.com/definition/dcim

--
djc

[Andrew Gabriel]

In article <54033022...@charleshope.demon.co.uk>,
charles <cha...@charleshope.demon.co.uk> writes:
> In article <hAR9v.201663$iZ5....@fx17.am4>, Ian Field

> <gangprob...@ntlworld.com> wrote:
>
>
>> "Rod Speed" <rod.sp...@gmail.com> wrote in message

>> news:bsq6c8...@mid.individual.net...
>> > P Jameson <58214...@mail.invalid> wrote
>> >

>> >> Poundland are doing a little cable with USB at one end and five
>> >> connections the other end to connect to a variety of different Smart
>> >> Phones. So you can charge your phone from your laptop.
>> >
>> >> Would the voltage likely be *steady* enough not to damage the phone
>> >> with 'spikes' ?
>> >

>> > Yes. The voltage is determined by the laptop, not that cable thing.
>> >
>> > The very fundamental problem tho is that there are a variety of ways
>> > those things signal how much current they need
>
>> In the original USB specification it was 100mA unless the target device
>> signalled otherwise, then a max 500mA was available.

It's still the case, but most USB ports don't police the current
drawn against that negotiated, although the USB hub chips commonly
used do include the logic to do so.

>> AFAIK that has largely been dropped and the full 500mA is usually
>> available by default.
>

>> A common scheme is "Polyfuse" protection - its a PTC thermistor that can
>> heat up with the current flowing through it, at a certain current it
>> heats enough to increase in resistance enough to practically stop
>> current flow.
>
>> When the overload is removed it cools and returns to low resistance, so
>> its self resetting.
>
> That could well explain why my "Nokia Smart Phone" refused to charge from a
> cheap car USB adaptor.

Nokia used a private scheme before USB power supported the passive
signalling with resistors on the USB data lines. If fed with < 5.5V,
the phone limited itself to low current draw. If fed with something
fractionally higher (which is illegal in the USB spec), the phone
assumed it was running from a charger and drew more current.

In theory, drawing more than 100mA required exchanging USB packets
to ask if it's possible to do so, which required at least some
microcontroller capability on the power driving side, which wasn't
practical for USB power supplies and chargers. The current spec
allows them to signal up to 2.1A available by the use of resistors
tied to the data lines.

In the current USB spec, much higher power is available by negotiation
(cranks up the voltage to limit the current in the connectors, and the
cable has to be suitable too). It's intended to provide enough power
to run a laptop. However, I've not yet seen any devices making use of
high supply voltage USB.

[Ian Field]

"Jim Lesurf" <no...@audiomisc.co.uk> wrote in message
news:5403a1d...@audiomisc.co.uk...

> In article <%yP9v.341541$Kq1.2...@fx07.am4>, Ian Field
> <gangprob...@ntlworld.com> wrote:
>
>
>> "Peter Duncanson" <ma...@peterduncanson.net> wrote in message
>> news:j1ffm91mtjpci6cb3...@4ax.com...
>> > On Mon, 5 May 2014 15:59:14 +0100, "P Jameson"
>
>> >>
>> > No. The adapter will contain electronics to reduce the voltage to what
>> > is needed by the phone and will regulate it.
>
>> I think the point is whether a �1 charge adapter is safe to use on say;
>> a �100 smartphone for instance.
>
>> If it uses a series pass transistor in the regulator, there's always a
>> possibility the transistor could fail short-circuit and dump the full
>> 12V on the USB connector.
>
>> How many corners did they cut to get it on the shelves at that price?!
>
> The discussion and low price bring to mind something I discovered years
> ago
> in kit supplied by someone.
>
> The kit required various 12V / 9V / 5V supplies for different items in the
> box. The 'designer' <sic> supplied some of the 9V or 5V by adding series
> resistors to the output from a 12V regulator.
>
> The result was predictable. The voltages varied as the items drew currents
> that weren't constant. Performance was awful. And in the end some of the -
> very costly - items failed due to drawing a 'lower than assumed' current,
> so experiencing high rail voltages.
>
> Caveat emptor. 8-/

These days, a large order of a popular SMPSU chip works out cheaper per part
than a row of fat power dropper resistors.

They can make the case a lot cheaper too, if there's not a lot of heat
generated.

[Ian Field]

"Max Demian" <max_d...@bigfoot.com> wrote in message

news:bsujg4...@mid.individual.net...

The better ones have a row of tappings on the secondary - but the regulation
still isn't great!

[Ian Field]

"John Williamson" <johnwil...@btinternet.com> wrote in message
news:bsucrp...@mid.individual.net...

There have been high profile prosecutions because formatted memory cards
aren't necessarily empty.

[Ian Field]

"Rod Speed" <rod.sp...@gmail.com> wrote in message

news:bst8uf...@mid.individual.net...

I might have been alluding to the fact that if it gets hot - the bin is the
best place for it.

[Jim Lesurf]

In article <__Odnbuwqe4nYvTOn...@bt.com>, Steve
Thackery

Yes. We had to spend about two-three months going though what had been
done and redesigning/rebuilding the kit. It was also plauged with RF loops,
leaks, etc.

By the time this all came to light the originator had changed job and
employer. Heaven knows what happened next!

[Johny B Good]

That's been the prime reason for using switching regulators in small
wallwart powered devices (ethernet switches, routers etc) for over a
decade now.

For once, a cost cutting measure that offers the end customer an even
greater benefit in that you can replace a faulty wallwart[1] with any
6 to 15 volt DC wallwart with a matching or greater VA rating with
impunity as long as the plug matches the socket.

If the plug doesn't match you can just cut the plug off the end of
the old wallwart and graft it onto the end of the replacement
walwart's lead (or, better still if you know how to use a toffee
hammer and a hot glue gun, swap the complete lead over to the new
wallwart).

This is an exercise I've done many times, usually to replace an
inefficient wallwart with a more efficient one to save a watt or two
on a 4 to 6 watt load. It's not a lot by itself but the savings can
mount up on a bunch of such kit that's typically running 24/7 year in
year out.

[1] Even the cheaper ac output transformer types can usually be
replaced by a DC output wallwart on account the input circuit of the
switching regulator has a fullwave bridge rectifier with a 16 or 25v
rated smoothing cap through which the DC from the wallwart will be
passed at the expense of about a 1.5 volt drop in the rectifier
bridge.

6 volts might not be quite enough in this case. A 7.5v minimum up to
a maximum of 15v should still be ok (and if the input cap has a 25v
rating, you can use even higher output voltages right up to 25v - no
artificial voltage veto as per the same circuitry typically used by
laptop makers).

[Johny B Good]

That's far from being a problem unique to memory cards. If you don't
have access to a PC of some sort with a secure erase/format utility,
you can always record a video or three after the in camera format
using the most memory expensive video format possible.

It might take a few hours to over-write the incriminating evidence
and need more than one video shot if hitting the 59 minute or 4GB
limit with larger media and quite possibly a change of battery to boot
but at least it's doable 'in the field' when away from a suitable PC.

A suitable scene to shoot such a movie of would be a distant scene at
maximum zoom to enhance the heat haze shimmer or the traffic flow on a
busy road to maximise the memory consumption rate. In the privacy of
your own home a movie of the TV tuned into an action movie broadcast
would also suffice. No worry about copyright infringement since you'll
be formatting the card as soon as you've done with obliterating the
evidence.

[Ian Field]

"Huge" <Hu...@nowhere.much.invalid> wrote in message
news:bsveo2...@mid.individual.net...

> On 2014-05-07, Jim Lesurf <no...@audiomisc.co.uk> wrote:
>> In article <__Odnbuwqe4nYvTOn...@bt.com>, Steve
>> Thackery
>><nob...@nowhere.com> wrote:
>>> Jim Lesurf wrote:
>>
>>> > The kit required various 12V / 9V / 5V supplies for different items in
>>> > the box. The 'designer' <sic> supplied some of the 9V or 5V by adding
>>> > series resistors to the output from a 12V regulator.
>>
>>> That is absolutely appalling!
>>
>> Yes. We had to spend about two-three months going though what had been
>> done and redesigning/rebuilding the kit. It was also plauged with RF
>> loops,
>> leaks, etc.
>>
>> By the time this all came to light the originator had changed job and
>> employer. Heaven knows what happened next!
>

> He went to work for Amstrad? :o)

I was trying to remember which hard-drive manufacturer Amstrad took to court
because their crappy drives were giving Amstrad a bad reputation.

[Rod Speed]

"Ian Field" <gangprob...@ntlworld.com> wrote in message

news:LQsav.253384$t73.2...@fx14.am4...

No, its still there in the quoting above.

[Ian Field]

"Rod Speed" <rod.sp...@gmail.com> wrote in message

news:bsvhi5...@mid.individual.net...

Like this you mean?:

[Rod Speed]

"Ian Field" <gangprob...@ntlworld.com> wrote in message

news:oBwav.235781$vM2.1...@fx18.am4...

No, your first mention of heat.

[Ian Field]

"Rod Speed" <rod.sp...@gmail.com> wrote in message

news:bsvn4u...@mid.individual.net...

As you've proven - I had to word things fairly broadly to allow for
dumbasses!

[Ian Field]

"dennis@home" <den...@killspam.kicks-ass.net> wrote in message
news:5368bf43$0$28554$c3e8da3$28e7...@news.astraweb.com...
> On 05/05/2014 22:42, Johny B Good wrote:
>
>> With a limit of just half an amp output, the chinese manufacturer
>> will be able to get away with mounting the chip straight onto the
>> circuit board with a blob of protective epoxy to stick it down to the
>> board (just like those cheap USB flash memory card adapters).
>
> There are good reasons why some electronics are like that.. its more
> reliable and is used in telecoms and military applications.
> Its only a problem if its done incorrectly.

For a start, the wire-bonds to the chip die have to be there whether they're
to PCB tracks or pins that will need soldering.

Solder joints were a reliability weak spot before dodgy RoHS solder.

Black-blob chips seemed to have flourished since RoHS.

[Ian Field]

"Andrew Gabriel" <and...@cucumber.demon.co.uk> wrote in message
news:lkd11u$650$1...@dont-email.me...

> In article <I9P9v.410200$H82.3...@fx23.am4>,
> "Ian Field" <gangprob...@ntlworld.com> writes:
>>
>> The car adaptor obviously has some kind of voltage regulator to drop the
>> 12V
>> down to 5V - at �1 you can afford to break one open and describe to us
>> what's in it so we can give better informed advice about any potential
>> risk.
>
> I've broken many open, to pinch the small switched mode PSU out of them
> to use for something else. I've never seen one with any protection against
> the FET shorting (which would generate 12V output), but I've never had
> that
> happen yet either.
>
> You can get ones which supply 4.2A now, for 2 x 2.1A USB outputs.

Having missed out at Poundland, I went in Lidl and this weeks weekly offers
include a �3.99 cig-socket adapter with generous assortment of pluggable
phone charging connectors.

Curiosity overcame my tight fisted ness - I'll crack it open later to see
what's in it.

[Ian Field]

"P Jameson" <58214...@mail.invalid> wrote in message
news:lk890l$3h8$1...@dont-email.me...

> Poundland are doing a little cable with USB at one end and five
> connections the other end to connect to a variety of different Smart
> Phones. So you can charge your phone from your laptop.
>
> Would the voltage likely be *steady* enough not to damage the phone with
> 'spikes' ?
>

> They also do an adapter to plug into the car cigarette socket with a USB
> femail socket built in. This will then accomodate the first mentioned
> lead.
>
> Would the cigarette socket also be likely to 'spike' and damage the phone?
>
> (dont ask how much they are).

Yesterday I managed to catch Poundland with some stock of USB adaptors (FX
Factory brand) I only wanted it to break open and see what's in it, and for
only �1 why not.

It uses the very popular MC34063 SMPSU chip, there was a low value resistor
on the PCB that could only be for the current sensing pins, so I didn't need
to trace out the circuit to find out.

Build quality is pretty much OK for something that only cost �1.

[Ian Field]

"Brian Gaff" <bri...@blueyonder.co.uk> wrote in message
news:lk89e2$72m$1...@dont-email.me...
> Well if they were dangerous, they should come with a warning, but if they
> start blowing up phones, even at the price you would probably have a claim
> against the shop if there was no warning.
> Brian

So far I've cracked open a �3.99 one from Lidl and another from Poundland,
neither looked conspicuously dodgy, but 12V down to 5V involves a buck
regulator that has a (switching) series pass transistor - if that fails
short circuit, the 12V will pass through like a dose of salts!

If the application is life support critical, any risk can be eliminated by a
thyristor "crowbar" failsafe circuit. Easy enough to splice a breakout box
into the lead or with a bit of manual dexterity could be squeezed into the
existing case.

Home Bargains have a cigarette adaptor for �1.49, but it only has a white
thin-wide connector - probably for ipad or something.

If you want a failsafe 12V to 5V converter; start with a buck converter that
produces 3.3V - then use a flyback converter to boost it back up to 5V.

If the flyback transistor fails; it shorts the output and produces no
voltage out - just in case the preceeding buck fails, its dead easy to rig
the flyback section to latch up on overvoltage, also producing no output.

[Johny B Good]

I notice there are ebay traders offering this chip in ten off
quantities at 99 pence, post free (Chinese suppliers) so you can see
why these things can be knocked out for just one pound a piece and
still allow for some profit (I'd imagine the rest of the bits would
probably soak up another 40 to 60 pence worth of component costs when
manufactured in bulk).

[Ian Field]

"Johny B Good" <johnny...@invalid.ntlworld.com> wrote in message
news:u2ccn95d66896dt50...@4ax.com...

I could probably find the chip a little cheaper in small quantity if I
searched hard enough, but I now have the chip ready assembled on a PCB with
all the components, that would be really simple to modify for any project I
might think up, and much easier than starting from scratch with prototyping
board.

You have to be careful ordering from overseas - Royal mail charge a
racketeering 'handling fee' to collect any duty, and I've heard some
carriers are even worse!!!

[Johny B Good]

On Fri, 16 May 2014 17:14:23 +0100, "Ian Field"

Very true! :-)

I wasn't suggesting it would be worthwhile buying the individual bits
yourself, just offering information as to how Pound Shops can sell
such _high_tech_ gadgets for _only_ one pound and _still_ make a
healthy profit.

>
>You have to be careful ordering from overseas - Royal mail charge a
>racketeering 'handling fee' to collect any duty, and I've heard some
>carriers are even worse!!!

A very good reason to make good use of a one pound item and modify it
to your purposes (i.e. an excellent example of why you _should_ fix
something that _isn't_ broken - you're simply improving it to suit
your needs).

[John Williamson]

On 17/05/2014 13:00, Johny B Good wrote:
> On Fri, 16 May 2014 17:14:23 +0100, "Ian Field"

>> I could probably find the chip a little cheaper in small quantity if I
>> searched hard enough, but I now have the chip ready assembled on a PCB with
>> all the components, that would be really simple to modify for any project I
>> might think up, and much easier than starting from scratch with prototyping
>> board.
>
> Very true! :-)
>
> I wasn't suggesting it would be worthwhile buying the individual bits
> yourself, just offering information as to how Pound Shops can sell
> such _high_tech_ gadgets for _only_ one pound and _still_ make a
> healthy profit.
>

Sometimes, while Poundland make a nice profit, the liquidators they
bought the stuff from are just grateful to get *any* money back.

Or the factory in China has a container or two full of stuff they can't
sell in China, as they've overestimated demand, so they get rid of it
for the cost of shipping.

There was a batch of radio microphones that appeared in all the markets
in France a while ago for a tenner, all from the same factory, of two
different types. I've never seen them since.

--
Tciao for Now!

John.

[Johny B Good]

The optimum way to guard against such a risk is to use a transformer
to magnetically couple the pulses. The final coupe de grace fat pulse
from the shorted transistor will only generate a few dozen extra
millivolts worth of surge at most, followed by a rapid decay of
voltage, followed a few milliseconds later by the safety fuse blowing.

[Ian Field]

"Johny B Good" <johnny...@invalid.ntlworld.com> wrote in message

news:3gpen9tjuiqpm2paf...@4ax.com...

I agree with that - but you're not going to get a transformer at those
prices.

[Ian Field]

"Johny B Good" <johnny...@invalid.ntlworld.com> wrote in message

news:8gjen91hk2478mjsu...@4ax.com...

At one point I ordered a quantity of 34063, I only wanted one but there was
a minimum order condition.

In the end I used a different chip so the ones I bought are still in the
parts drawer.