Power adaptor question

[ChrisW]

I have a device which uses 9V 500mA. I am wondering if I can use a
regulated switchmode 9V 2A power adaptor without damaging the device.

 

[Eeyore]

ChrisW wrote:

I have a device which uses 9V 500mA. I am wondering if I can use a
regulated switchmode 9V 2A power adaptor without damaging the device.

Yes.

The current rating on power supplies is simply the maximum they can
deliver without overheating, damage or shutdown. The 'device'simply takes
as much current as it needs.

Same with the electricity supply to a house. It may be rated at 100A for
example but you only use what's required.

Graham

 

[Mike]

On Sun, 23 Dec 2007 22:55:51 -0800 (PST), ChrisW <sanufi@gmail.com> wrote:

I have a device which uses 9V 500mA. I am wondering if I can use a
regulated switchmode 9V 2A power adaptor without damaging the device.

Yes you can. The 2A rating is where it will either shutdown or start overheating
and your 1/2A load will not approach the 2A so you'll be fine.

Mike

"The scientist is possessed by the sense of universal
causation...His religious feeling takes the form of
rapturous amazement at the harmony of natural law,
which reveals the intelligence of such superiority
that, compared with it, systematic thinking and acting
of human beings is an utterly insignificant reflection."
Albert Einstein (theoretical physicist)

 

[Eeyore]

Chris wrote:

On Dec 24, 12:55 am, ChrisW <san...@gmail.com> wrote:
I have a device which uses 9V 500mA. I am wondering if I can use a
regulated switchmode 9V 2A power adaptor without damaging the device.

I'm not entirely sure you have a 9VDC@2A wall wart adapter or another
form of switchmode power supply. All switching DC wall warts are made
to handle no-load condition, but many switching power supplies require
a minimum load. Also, if you plug power into a jack on the device
which requires a male power plug, you may have to be concerned about
momentary short circuit while you're plugging it in. The old
unregulated DC wall warts could handle that without problem, but
switching wall warts may or may not be able to handle it. The good
news is that switching wall warts usually can. But if it can't, to
protect the switching power supply you might have to unplug the wall
wart before you remove the plug from the device.

Is this mere speculation on your part ?

Graham

 

[Chris]

On Dec 24, 12:55 am, ChrisW <san...@gmail.com> wrote:

I have a device which uses 9V 500mA. I am wondering if I can use a
regulated switchmode 9V 2A power adaptor without damaging the device.

I'm not entirely sure you have a 9VDC@2A wall wart adapter or another
form of switchmode power supply. All switching DC wall warts are made
to handle no-load condition, but many switching power supplies require
a minimum load. Also, if you plug power into a jack on the device
which requires a male power plug, you may have to be concerned about
momentary short circuit while you're plugging it in. The old
unregulated DC wall warts could handle that without problem, but
switching wall warts may or may not be able to handle it. The good
news is that switching wall warts usually can. But if it can't, to
protect the switching power supply you might have to unplug the wall
wart before you remove the plug from the device.

Whether or not the power supply can handle it, I'm sure your device
will be OK.

Cheers
Chris

 

[Chris]

On Dec 24, 9:41 am, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:

Chris wrote:
On Dec 24, 12:55 am, ChrisW <san...@gmail.com> wrote:
I have a device which uses 9V 500mA. I am wondering if I can use a
regulated switchmode 9V 2A power adaptor without damaging the device.

I'm not entirely sure you have a 9VDC@2A wall wart adapter or another
form of switchmode power supply.  All switching DC wall warts are made
to handle no-load condition, but many switching power supplies require
a minimum load.  Also, if you plug power into a jack on the device
which requires a male power plug, you may have to be concerned about
momentary short circuit while you're plugging it in.  The old
unregulated DC wall warts could handle that without problem, but
switching wall warts may or may not be able to handle it.  The good
news is that switching wall warts usually can.  But if it can't, to
protect the switching power supply you might have to unplug the wall
wart before you remove the plug from the device.

Is this mere speculation on your part ?

Graham- Hide quoted text -

- Show quoted text -

Hi, Graham. Some switcher wall warts come with the female-type plug
(fits into a center pin on the device being powered), and I've heard
one reason for that is that it prevents shorting the switcher when
plugging in.

But it *is* speculation on my part, and definitely shouldn't be taken
without a grain of salt. The OP could easily momentarily short the
wall wart output with a jumper wire, and see if the power supply
survives.

I'm sure that either way, nothing will happen to the OP's device,
which was his basic question. That is, assuming the switcher wall
wart has the right type of plug and the polarity is correct.

Thanks for the spot, sir.

Happy Holidays
Chris