Electrical Engineering - replacing any power adapter

Author

replacing any power adapter - what to check?

gavin@my-deja.com

2008-03-13, 8:25 pm

OK! quicky question about power adapters:

If I need to replace a power adapter for a gadget I need to check the
following I( think):

1) the adapter can supply 110-240 volts (switching) - this is only a
*must check* if its a foreign device for example
2) The correct current type will be supplied (AC or DC)
3) The voltage is in the correct range (e.g. 5v)
4) the frequency is correct (e.g. 50-60Hz)

Now how about the current? For example the adapter for my laptop has
a picture of a line with a dotted line underneath then the value 6.7A
as the output... what is this saying? If I am replacing a device's
adapter - need I worry about this value?

Anything else one needs to check to avoid fires/explosions?

thanks and sorry for the somewhat trivial nature of the query - I am
guessing the readers of this group are well positioned to know the
answers however.

Gav

ehsjr

2008-03-14, 3:25 am

gavin@my-deja.com wrote:
> OK! quicky question about power adapters:
>
> If I need to replace a power adapter for a gadget I need to check the
> following I( think):
>
> 1) the adapter can supply 110-240 volts (switching) - this is only a
> *must check* if its a foreign device for example
> 2) The correct current type will be supplied (AC or DC)
> 3) The voltage is in the correct range (e.g. 5v)
> 4) the frequency is correct (e.g. 50-60Hz)
>
> Now how about the current? For example the adapter for my laptop has
> a picture of a line with a dotted line underneath then the value 6.7A
> as the output... what is this saying? If I am replacing a device's
> adapter - need I worry about this value?

Yes. That 6.7A rating tells you that the adapter is capable of
providing up to 6.7 amps of current to the device. The new
adapter must be able to supply the maximum current that the device
will draw. The correct way to determine what the device will
draw is in the device ratings - not in the adapter ratings. If
you don't have documentation on that, then you can assume 6.7A
and get a suitable replacement adapter capable of that current.

Ed

>
> Anything else one needs to check to avoid fires/explosions?
>
> thanks and sorry for the somewhat trivial nature of the query - I am
> guessing the readers of this group are well positioned to know the
> answers however.
>
> Gav
>
>

Anthony Guzzi

2008-03-14, 3:25 am

gavin@my-deja.com wrote:
> OK! quicky question about power adapters:
>
> If I need to replace a power adapter for a gadget I need to check the
> following I( think):
>
> 1) the adapter can supply 110-240 volts (switching) - this is only a
> *must check* if its a foreign device for example
> 2) The correct current type will be supplied (AC or DC)
> 3) The voltage is in the correct range (e.g. 5v)
> 4) the frequency is correct (e.g. 50-60Hz)
>
> Now how about the current? For example the adapter for my laptop has
> a picture of a line with a dotted line underneath then the value 6.7A
> as the output... what is this saying? If I am replacing a device's
> adapter - need I worry about this value?
>
> Anything else one needs to check to avoid fires/explosions?
>
> thanks and sorry for the somewhat trivial nature of the query - I am
> guessing the readers of this group are well positioned to know the
> answers however.
>
> Gav
>
>

I thought there was something to do with polarity, but I don't know the
details. There's a little symbol with a plus and an arrow or something.

Rheilly Phoull

2008-03-14, 9:25 am

"gavin@my-deja.com" <gavink151@gmail.com> wrote in message
news:230f95c2-1d71-4c65-bafb-038951cdc0a6@s19g2000prg.googlegroups.com...
> OK! quicky question about power adapters:
>
> If I need to replace a power adapter for a gadget I need to check the
> following I( think):
>
> 1) the adapter can supply 110-240 volts (switching) - this is only a
> *must check* if its a foreign device for example
> 2) The correct current type will be supplied (AC or DC)
> 3) The voltage is in the correct range (e.g. 5v)
> 4) the frequency is correct (e.g. 50-60Hz)
>
> Now how about the current? For example the adapter for my laptop has
> a picture of a line with a dotted line underneath then the value 6.7A
> as the output... what is this saying? If I am replacing a device's
> adapter - need I worry about this value?
>
> Anything else one needs to check to avoid fires/explosions?
>
> thanks and sorry for the somewhat trivial nature of the query - I am
> guessing the readers of this group are well positioned to know the
> answers however.
>
> Gav
>
>
Yup, the dotted and continuous lines represent a DC input. The polarity
(Positive or negative) is important with regards to which pin on the input
connector gets positive or the negative (usually the centre pin is positive
but not always with the round jacks) you have to get it right.

--
Cheers ............. Rheilly

151

2008-03-14, 9:25 am

On Mar 14, 2:57 am, ehsjr <eh...@bellatlantic.net> wrote:
> ga...@my-deja.com wrote:
>
>
>
>
> Yes. That 6.7A rating tells you that the adapter is capable of
> providing up to 6.7 amps of current to the device. The new
> adapter must be able to supply the maximum current that the device
> will draw. The correct way to determine what the device will
> draw is in the device ratings - not in the adapter ratings. If
> you don't have documentation on that, then you can assume 6.7A
> and get a suitable replacement adapter capable of that current.
>
> Ed
>

hi (and thanks all who replied!)

ok so what happens if the adapter cant supply the current the device
wants to draw? is there any serious risk or will it simply not work?

[color=darkred]
>
>
>

ehsjr

2008-03-15, 3:25 am

151 wrote:
> On Mar 14, 2:57 am, ehsjr <eh...@bellatlantic.net> wrote:
>
>
>
> hi (and thanks all who replied!)
>
> ok so what happens if the adapter cant supply the current the device
> wants to draw? is there any serious risk or will it simply not work?
>
>
>
>

The adapter could burn out. Further "serious risk"
(like flames? meltdown? not sure what you have in
mind) is not likely - but you can't declare it
totally impossible, either. Adapters are supposed
to be built to prevent overheating to the point
they catch on fire or melt.

Ed

dirskyster@gmail.com

2008-03-15, 9:25 am

On 3=D4=C214=C8=D5, =C9=CF=CE=E76=CA=B146=B7=D6, "ga...@my-deja.com" <gavink=
....@gmail.com> wrote:
> OK! quicky question about power adapters:
>
> If I need to replace a power adapter for a gadget I need to check the
> following I( think):
>
> 1) the adapter can supply 110-240 volts (switching) - this is only a
> *must check* if its a foreign device for example
> 2) The correct current type will be supplied (AC or DC)
> 3) The voltage is in the correct range (e.g. 5v)
> 4) the frequency is correct (e.g. 50-60Hz)
>
> Now how about the current? For example the adapter for my laptop has
> a picture of a line with a dotted line underneath then the value 6.7A
> as the output... what is this saying? If I am replacing a device's
> adapter - need I worry about this value?
>
> Anything else one needs to check to avoid fires/explosions?
>
> thanks and sorry for the somewhat trivial nature of the query - I am
> guessing the readers of this group are well positioned to know the
> answers however.
>
> Gav

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dirskyster@gmail.com

2008-03-15, 9:25 am

dirskyster@gmail.com

2008-03-16, 1:25 pm

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