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 Use 3A power supply with 2.5A device? 
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Post Use 3A power supply with 2.5A device?
Hello,

I am not very knowledgeable when it comes to electricity. I have a
wireless router that takes an input of 5V/2.5A but I lost the power
supply for it. I have another power supply from another wireless
router that is 5V/3A. I heard that Volts can fluctuate a bit but Amps
have to be dead on (or below).

Will this power supply work with my router or do I have to go out and
buy a new one? Thanks!

Regan


17 Mar 2008, 14:01
Post Re: Use 3A power supply with 2.5A device?
"Regan" <reiklen@gmail.com> wrote in message
news:d5fc43c1-b79e-4c7a-bd11-c456097fa413@v29g2000hsf.googlegroups.com...
> Hello,
>
> I am not very knowledgeable when it comes to electricity. I have a
> wireless router that takes an input of 5V/2.5A but I lost the power
> supply for it. I have another power supply from another wireless
> router that is 5V/3A. I heard that Volts can fluctuate a bit but Amps
> have to be dead on (or below).
>
> Will this power supply work with my router or do I have to go out and
> buy a new one? Thanks!
>

Yes it will. The voltage needs to be about the same because higher the
voltage the more current it will draw and the hotter it will get. The lower
the voltage the less current which might not be enough(although I've ran
some devices with 2V below what they "needed").

The current is also variable but if you don't give it enough current then it
probably won't work well. You can always give it "more" but realize that
devices actually only use as much current as they "need"(which depends on
the voltage so getting the voltage right is the main issue).

If a device requires X volts then it needs X volts(+- 1V in most cases will
be ok) and if it "needs" Y amps then it means it needs *ATLEAST* Y amps.
You can give it 100 times Y and be ok because it will still only use Y amps.

Make sure you get the polarity right too.


17 Mar 2008, 14:01
Post Re: Use 3A power supply with 2.5A device?
In <d5fc43c1-b79e-4c7a-bd11-c456097fa413@v29g2000hsf.googlegroups.com>,
Regan wrote:
>
>I am not very knowledgeable when it comes to electricity. I have a
>wireless router that takes an input of 5V/2.5A but I lost the power
>supply for it. I have another power supply from another wireless
>router that is 5V/3A. I heard that Volts can fluctuate a bit but Amps
>have to be dead on (or below).
>
>Will this power supply work with my router or do I have to go out and
>buy a new one? Thanks!

Volts need to match, and amps of the load need to be same as or less
than the amp rating of the power supply.

Unregulated power supplies, especially "wall warts", tend to have volts
going high when amps taken is far below what they are rated for. However,
I see no problem with putting a 2.5 amp load on a 3 amp supply. I would
worry a little bit if the power supply is an unregulated wallwart and the
amps taken is less than half the wallwart's rating. For that matter, I
suspect that 5 volt ones over 3/4 amp or so tend to be regulated.

I say go for it. (My warranty - if things go wrong, I refund what I got
paid to post this and do nothing more.)

- Don Klipstein (don@misty.com)


17 Mar 2008, 14:01
Post Re: Use 3A power supply with 2.5A device?
On Mon, 7 Jan 2008 17:53:16 -0800 (PST), Regan <reiklen@gmail.com>
wrote:

>Hello,
>
>I am not very knowledgeable when it comes to electricity. I have a
>wireless router that takes an input of 5V/2.5A but I lost the power
>supply for it. I have another power supply from another wireless
>router that is 5V/3A. I heard that Volts can fluctuate a bit but Amps
>have to be dead on (or below).
>
>Will this power supply work with my router or do I have to go out and
>buy a new one? Thanks!

It'll be fine. Tme important thing is the available current from
power supply is greater than required current input while the voltage
is the same. Check polarity as well, your router may not have
diode(s)to handle reverse polarity and reverse polarity can destroy
your router.

Let me try to simplify trhe voltage vs current: think of electricity
as water pipe. The voltage is the pressure that pushes the water (or
electricity) through and too high of voltage will cause burn out or
worse. Current is the measurement of electricity flowing through in
one period.

So matching voltage is important but the supply current only needs to
be equal or higher than required input of the device as the device
will only draw as needed and not more. Low current source like a
cheap power supply will defiantly overload trying to provide more
current than it's capable of.


17 Mar 2008, 14:02
Post Re: Use 3A power supply with 2.5A device?
On Mon, 7 Jan 2008 17:53:16 -0800 (PST), Regan <reiklen@gmail.com> wrote:

:Hello,
:
:I am not very knowledgeable when it comes to electricity. I have a
:wireless router that takes an input of 5V/2.5A but I lost the power
:supply for it. I have another power supply from another wireless
:router that is 5V/3A. I heard that Volts can fluctuate a bit but Amps
:have to be dead on (or below).
:
:Will this power supply work with my router or do I have to go out and
:buy a new one? Thanks!
:
:Regan


Not exactly correct. You MUST use a suitable power supply with the SAME voltage
and AT LEAST the same current output rating. The output cable plug MUST have the
same polarity as the original.

You can't afford to allow the voltage to fluctuate significantly from the stated
5V and the PSU must be capable of supplying the maximum stated current without
the voltage sagging by more than a couple of hundred mV max at full rated load.
For the 5V/3A supply this will undoubtedly be a regulated switch mode unit, and
since the original unit was only rated at 2.5A, it will have a greater overhead
margin and thus will be even more capable of accurately maintaining the 5V
output at the current determined by the load.


17 Mar 2008, 14:02
Post Re: Use 3A power supply with 2.5A device?
On 8 jan, 02:53, Regan <reik...@gmail.com> wrote:
> Hello,
>
> I am not very knowledgeable when it comes to electricity. I have a
> wireless router that takes an input of 5V/2.5A but I lost the power
> supply for it. I have another power supply from another wireless
> router that is 5V/3A. I heard that Volts can fluctuate a bit but Amps
> have to be dead on (or below).
>
> Will this power supply work with my router or do I have to go out and
> buy a new one? Thanks!
>
> Regan

hello
i thinks to buy a new power supply or wireless router


17 Mar 2008, 14:02
Post Re: Use 3A power supply with 2.5A device?
On 8 jan, 02:53, Regan <reik...@gmail.com> wrote:
> Hello,
>
> I am not very knowledgeable when it comes to electricity. I have a
> wireless router that takes an input of 5V/2.5A but I lost the power
> supply for it. I have another power supply from another wireless
> router that is 5V/3A. I heard that Volts can fluctuate a bit but Amps
> have to be dead on (or below).
>
> Will this power supply work with my router or do I have to go out and
> buy a new one? Thanks!
>
>I think to you power supply 5V3A it's not compatible with your wireless router because the current he produce to much current and he risk burning out then its necessary to change your power supply or your wireless router.


17 Mar 2008, 14:02
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