replacing any power adapter - what to check?

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
Reply to
gavink151
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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
Reply to
ehsjr
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.
Reply to
Anthony Guzzi
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.
Reply to
Rheilly Phoull
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?
Reply to
151
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
Reply to
ehsjr

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