'Wall wart' power supplies: voltage?

Here's one possibly for Jeff L as a follow up to my earlier Buffalo adaptor
thread (the header of which I would insert here except that when I do it
comes out as minute times new roman for some stupid reason!).

It turns out that the unpowered sitecom pocket hub I had been trying to use,
does in fact have a socket for an external power supply, which I had not
noticed and was not referred to in the user guide. (It turns out there is
one FAQ on the sitecom site, and it is about which supply to use, and it
would appear that my one from the old D-link router will do - once it has
the right plug...)

Now, I have a number of power supply 'wall warts' from succesive cell
phones, routers etc. and would like to use one of these rather than just buy
yet another one.

Curiously, when I check the voltages of some of these devices it seems to be
wildly at variance with what I understsand of what appears on the labels.

For example, I have a FRIWO FW 4199, which is supposedly 5V (equals sign
with the bottom line as three dashes - what does this mean exactly: have
been unable to look it up!) 410mA 2.05VA which both my old avo meters tell
me is 9V not 5.

I also have a Sony AC-MZR37 which says 4.5V (same symbol) 500mA, which my
meters tell me is turning out 7.5 V.

Another Nokia phone charger we have emits a high pitched whine...

Other 'warts' that I have do measure as what they are supposed to be, so
what is going on? Are these devices just very unreliable or very difficult
to measure, and what does this mean for the devices they are meant to power?

I was quite surprised to have to come back here with this question, but none
of the manufacturer's sites I tried even seemed to have anywhere to look
this sort of thing up, and I did not have a way of searching for the symbol
with the broken equals sign. I probably ought to know what it means but it
is a long time since I read any of this basic stuff and now I don't know
where to!

Cheers,

S

Addenda:

I should have noted that the '4.5V' 500mA Sony supply is the only one that
has the right plug on the end: so if the problem is just the way I've been
measuring it, this would be my logical first choice to try powering the
oocket hub with...

S


"Steve H" <(E-Mail Removed)> wrote in message
news:tKBLh.12397$(E-Mail Removed)...
> Here's one possibly for Jeff L as a follow up to my earlier Buffalo
> adaptor
> thread (the header of which I would insert here except that when I do it
> comes out as minute times new roman for some stupid reason!).
>
> It turns out that the unpowered sitecom pocket hub I had been trying to
> use,
> does in fact have a socket for an external power supply, which I had not
> noticed and was not referred to in the user guide. (It turns out there is
> one FAQ on the sitecom site, and it is about which supply to use, and it
> would appear that my one from the old D-link router will do - once it has
> the right plug...)
>
> Now, I have a number of power supply 'wall warts' from succesive cell
> phones, routers etc. and would like to use one of these rather than just
> buy
> yet another one.
>
> Curiously, when I check the voltages of some of these devices it seems to
> be
> wildly at variance with what I understsand of what appears on the labels.
>
> For example, I have a FRIWO FW 4199, which is supposedly 5V (equals sign
> with the bottom line as three dashes - what does this mean exactly: have
> been unable to look it up!) 410mA 2.05VA which both my old avo meters tell
> me is 9V not 5.
>
> I also have a Sony AC-MZR37 which says 4.5V (same symbol) 500mA, which my
> meters tell me is turning out 7.5 V.
>
> Another Nokia phone charger we have emits a high pitched whine...
>
> Other 'warts' that I have do measure as what they are supposed to be, so
> what is going on? Are these devices just very unreliable or very
> difficult
> to measure, and what does this mean for the devices they are meant to
> power?
>
> I was quite surprised to have to come back here with this question, but
> none
> of the manufacturer's sites I tried even seemed to have anywhere to look
> this sort of thing up, and I did not have a way of searching for the
> symbol
> with the broken equals sign. I probably ought to know what it means but
> it
> is a long time since I read any of this basic stuff and now I don't know
> where to!
>
> Cheers,
>
> S
>
>
>

"Steve H" <(E-Mail Removed)> wrote in
news:tKBLh.12397$(E-Mail Removed):


> Other 'warts' that I have do measure as what they are supposed to be,
> so what is going on? Are these devices just very unreliable or very
> difficult to measure, and what does this mean for the devices they are
> meant to power?

It all depends on the design. Some may be simply a transformer w/a DC
bridge rectifier. Others may be regulated after the DC rectifier, or
provide AC-DC isolation. Others may be switching supplies, which require a
load to get a true reading of the voltage. The cheapest one's are usually
simple DC bridge rectifiers w/o regulation.

As for the devices they power....again, depends on the device.

Typically, a device will have an internal regulator that cuts the voltage
down even more. If it calls for a 5V supply, there is probably a 3.3v
regulator inside the device. While a 5v device will most likely function
with a 9VDC supply, it may not for long. The regulator inside will get very
hot, very quickly, and possibly burn up, if it is a standard 7805-like
(linear) regulator.

This symbol: ____
----

Means it is a DC output. Yes, I have seen AC output wall adapters.

It's best just to use one that you have that outputs the correct voltage
right off the bat.

On Mon, 19 Mar 2007 19:44:25 GMT, "Steve H"
<(E-Mail Removed)> wrote:

>It turns out that the unpowered sitecom pocket hub I had been trying to use,
>does in fact have a socket for an external power supply, which I had not
>noticed and was not referred to in the user guide.

USB power is always 5.0VDC at whatever current is necessary. That's
usually 0.5A per port. So, if your pocket hub has 4 ports, you'll
need 2Amps of current capeability. Also note that there's a very big
difference between a battery charger (as detailed in your cell phone
and camera examples), and a battery eliminator (as required by this
USB contrivance). I'll spare you the details (unless you want them).

Does $14 including shipping work for you?
<http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250009707289>
You didn't say anything about the connector, so I can't be sure it
will just plug into your Sitecom USB hub.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558 (E-Mail Removed)
# http://802.11junk.com (E-Mail Removed)
# http://www.LearnByDestroying.com AE6KS

Jeff Liebermann <(E-Mail Removed)> wrote in
news:(E-Mail Removed):

> On Mon, 19 Mar 2007 19:44:25 GMT, "Steve H"
> <(E-Mail Removed)> wrote:
>
>>It turns out that the unpowered sitecom pocket hub I had been trying
>>to use, does in fact have a socket for an external power supply, which
>>I had not noticed and was not referred to in the user guide.
>
> USB power is always 5.0VDC at whatever current is necessary. That's
> usually 0.5A per port. So, if your pocket hub has 4 ports, you'll
> need 2Amps of current capeability. Also note that there's a very big
> difference between a battery charger (as detailed in your cell phone
> and camera examples), and a battery eliminator (as required by this
> USB contrivance). I'll spare you the details (unless you want them).
>
> Does $14 including shipping work for you?
> <http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250009707289>
> You didn't say anything about the connector, so I can't be sure it
> will just plug into your Sitecom USB hub.
>
>

Hey Jeff,

Whenever I'm looking for a wall adapter, the first place I look is
Hosfelt.

www.hosfelt.com wall adapters are listed under 'Adapter' on the left
side.

The stock constantly changes, and right now they don't have as much as
usual, but worth looking at if you need one. this is where I bought the
18VAC output wall adapter I mentioned in my post.

Thanks again Jeff and Dan,

That clears up a few things, and reassures me me or my meter weren't going
mad after all!

Here in the UK, things are not as cheap as they are out your way, so I will
refrain from buying a dedicated new adapter just yet, as the adapter from my
defunct D-Link router is correct for the USB hub bar the plug - which I will
now swap over, and hopefully then prove that it was just lack of power that
was the problem with my Buffalo USB wireless adaptor.

Cheers,

S


"DanS" <(E-Mail Removed)> wrote in message
news:Xns98F8CC5155049thisnthatadelphianet@194.177. 96.78...
> Jeff Liebermann <(E-Mail Removed)> wrote in
> news:(E-Mail Removed):
>
>> On Mon, 19 Mar 2007 19:44:25 GMT, "Steve H"
>> <(E-Mail Removed)> wrote:
>>
>>>It turns out that the unpowered sitecom pocket hub I had been trying
>>>to use, does in fact have a socket for an external power supply, which
>>>I had not noticed and was not referred to in the user guide.
>>
>> USB power is always 5.0VDC at whatever current is necessary. That's
>> usually 0.5A per port. So, if your pocket hub has 4 ports, you'll
>> need 2Amps of current capeability. Also note that there's a very big
>> difference between a battery charger (as detailed in your cell phone
>> and camera examples), and a battery eliminator (as required by this
>> USB contrivance). I'll spare you the details (unless you want them).
>>
>> Does $14 including shipping work for you?
>> <http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250009707289>
>> You didn't say anything about the connector, so I can't be sure it
>> will just plug into your Sitecom USB hub.
>>
>>
>
> Hey Jeff,
>
> Whenever I'm looking for a wall adapter, the first place I look is
> Hosfelt.
>
> www.hosfelt.com wall adapters are listed under 'Adapter' on the left
> side.
>
> The stock constantly changes, and right now they don't have as much as
> usual, but worth looking at if you need one. this is where I bought the
> 18VAC output wall adapter I mentioned in my post.
>
>

And the result is ... see back at the Buffalo adaptor thread...

S

"spamlet" <(E-Mail Removed)> wrote in message
news:YlQLh.12325$(E-Mail Removed)...
> Thanks again Jeff and Dan,
>
> That clears up a few things, and reassures me me or my meter weren't going
> mad after all!
>
> Here in the UK, things are not as cheap as they are out your way, so I
> will refrain from buying a dedicated new adapter just yet, as the adapter
> from my defunct D-Link router is correct for the USB hub bar the plug -
> which I will now swap over, and hopefully then prove that it was just lack
> of power that was the problem with my Buffalo USB wireless adaptor.
>
> Cheers,
>
> S
>
>
> "DanS" <(E-Mail Removed)> wrote in message
> news:Xns98F8CC5155049thisnthatadelphianet@194.177. 96.78...
>> Jeff Liebermann <(E-Mail Removed)> wrote in
>> news:(E-Mail Removed):
>>
>>> On Mon, 19 Mar 2007 19:44:25 GMT, "Steve H"
>>> <(E-Mail Removed)> wrote:
>>>
>>>>It turns out that the unpowered sitecom pocket hub I had been trying
>>>>to use, does in fact have a socket for an external power supply, which
>>>>I had not noticed and was not referred to in the user guide.
>>>
>>> USB power is always 5.0VDC at whatever current is necessary. That's
>>> usually 0.5A per port. So, if your pocket hub has 4 ports, you'll
>>> need 2Amps of current capeability. Also note that there's a very big
>>> difference between a battery charger (as detailed in your cell phone
>>> and camera examples), and a battery eliminator (as required by this
>>> USB contrivance). I'll spare you the details (unless you want them).
>>>
>>> Does $14 including shipping work for you?
>>> <http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250009707289>
>>> You didn't say anything about the connector, so I can't be sure it
>>> will just plug into your Sitecom USB hub.
>>>
>>>
>>
>> Hey Jeff,
>>
>> Whenever I'm looking for a wall adapter, the first place I look is
>> Hosfelt.
>>
>> www.hosfelt.com wall adapters are listed under 'Adapter' on the left
>> side.
>>
>> The stock constantly changes, and right now they don't have as much as
>> usual, but worth looking at if you need one. this is where I bought the
>> 18VAC output wall adapter I mentioned in my post.
>>
>>
>
>

Steve H wrote:

> Other 'warts' that I have do measure as what they are supposed to be, so
> what is going on? Are these devices just very unreliable or very difficult
> to measure, and what does this mean for the devices they are meant to power?

The ones that measure as indicated are regulated. The ones that measure
higher are unregulated. If it were possible to measure the voltage of
the unregulated wall wart when it was plugged into the device it is
intended for, it would be about the right voltage under that load.

The symbol with the line and three dashes is for DC.

Unregulated supplies save the manufacturer a few cents in manufacturing,
and the device it powers (or charges) is designed to work with a wide
enough voltage range so it doesn't affect it.

Here's one supply that should work, once you put on the proper tip
"http://www.allelectronics.com/cgi-bin/item/PS-537/480/5VDC_3.7A_SWITCHING_POWER_SUPPLY_.html"

Thanks for the extra info SMS: it is good to find so many helpful people
about!

The allelectronics supply does look amazingly good value (though in the UK I
won't be able to take advantage of this).

The Sitecom FAQ recommended a 2.5A supply, and this coincided with the
supply I still had from a router recently replaced, so I used this to see if
my pocket hub would power the troublesome Buffalo WLI-U2-KG54-AI USB
wireless adaptor I have been trying to make work in my laptop (Inspiron
2600) - the subject of quite a long earlier thread you may have missed.

I can report back that even with the additional power to the USB hub, the
wireless adaptor will not start on the laptop though it works fine on the
pc. If you see the other thread you will find that that just about exhausts
every avenue I can think of as to why the device may not work in the laptop.
Buffalo still have not got back to me with any further suggestions either...

Thanks once again,

S
"SMS" <(E-Mail Removed)> wrote in message
news:4600623c$0$27198$(E-Mail Removed)...
> Steve H wrote:
>
>> Other 'warts' that I have do measure as what they are supposed to be, so
>> what is going on? Are these devices just very unreliable or very
>> difficult
>> to measure, and what does this mean for the devices they are meant to
>> power?
>
> The ones that measure as indicated are regulated. The ones that measure
> higher are unregulated. If it were possible to measure the voltage of the
> unregulated wall wart when it was plugged into the device it is intended
> for, it would be about the right voltage under that load.
>
> The symbol with the line and three dashes is for DC.
>
> Unregulated supplies save the manufacturer a few cents in manufacturing,
> and the device it powers (or charges) is designed to work with a wide
> enough voltage range so it doesn't affect it.
>
> Here's one supply that should work, once you put on the proper tip
> "http://www.allelectronics.com/cgi-bin/item/PS-537/480/5VDC_3.7A_SWITCHING_POWER_SUPPLY_.html"

Steve H wrote:
> Thanks for the extra info SMS: it is good to find so many helpful people
> about!
>
> The allelectronics supply does look amazingly good value (though in the UK I
> won't be able to take advantage of this).
>
> The Sitecom FAQ recommended a 2.5A supply, and this coincided with the
> supply I still had from a router recently replaced, so I used this to see if
> my pocket hub would power the troublesome Buffalo WLI-U2-KG54-AI USB
> wireless adaptor I have been trying to make work in my laptop (Inspiron
> 2600) - the subject of quite a long earlier thread you may have missed.

I'd suspect the laptop a lot more than the USB Wireless adapter.

I have a lot of experience troubleshooting USB issues, and often it's
the host controller, the processor, or the USB driver that are the cause
of USB problems, rather than the USB device. The problems are
exacerbated when it goes through a hub. It can even work for a while
just fine, then start screwing up.

I.e. see "http://81.5.185.34/tc-one-thousand/issues.html#USBFunc" which
turned out to be a driver problem that was never discovered until a
specific combination of processor and USB host controller exacerbated
the problem. The processor would be servicing other PCI devices and the
USB would time-out and disconnect when it should have waited for the
processor, then the system would rediscover the USB device, and it would
work for a while then disconnect again. This was a very difficult USB
issue to troubleshoot, requiring renting an expensive USB analyzer to
see what was going on. The failure didn't occur when connected directly
to the USB port on the system, only when connected through a USB 2.0 hub
which was in the docking station. Fortunately there was a fix in the
processor's firmware that solved the problem, and was able to be
downloaded and installed by the user.

You might want to check if there was ever an updated USB driver for that
notebook.

In any case, I'd give up and buy a Cardbus wireless adapter, unless you
need the CardBus slot for something else.