A question for the Hardware Geeks Among Us...

[Jackpine Radical]

I have a new Fujitsu laptop with a power supply that puts out 19 volts and 3.16 amps.

My old laptop's power supply puts out 19 volts and 3.95 amps. The barrel connecters seem interchangeable, and both have positive centers. Can I use them interchangeably? I have extra power supplies for my old machine so I can plug it in at home or at either of my offices without having to lug the power supplies around.

My suspicion is that I can use the chargers from the old machines for the new one, but obviously I don't want to do anything that would harm my machines.

Anybody got sensible advice here?

[Guy Fawkes]

1. Don't do it,

you could wind up frying your new laptop. Also, electrical fires are bad.

[artfan]

2. I would not

odds are it would be OK but could burn out power supply and will almost certainly void any warranty.

[benburch]

3. I'd do it.

And I've been an engineer for years.

I would not want to reverse that though. The smaller supply would likely overheat and shut down on the older machine.

[IowaGuy]

4. Absolutely correct...

The ampweage rating is the max the transformer can deliver at that voltage. If the voltage, cycles, phasing are the same (and in all likelihood are in this case) then the laptop will only draw the amps it needs. This is somewhat analogous to putting a bigger gas line and gas tank on your car....won't hurt it or make it go any faster, you would just have more capacity than you had before.

[phreakwars]

5. Yes it would work

The laptop is only going to draw the AMPs it needs anyway. The only way you could damage it, is by putting on a power supply with LESS amps to draw on.
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[benburch]

6. Then you'd likely hurt the power supply before you'd hurt the laptop.

Though when the voltage drops, because you are overloading that small supply, the voltage regulators in the laptop might not be able to cope. Depends on the design. I'd definitely not put the lower rated supply on the older machine.

[Jackpine Radical]

7. Thanks everyone.

I hadn't contemplated using the lower-amperage supply on the old machine. I certainly won't do that, but it sounds like I won't have to get lower-amp chargers to match the rating of the one on my new machine.

[MazeRat7]

8. New Laptop + Old supply = OK. Old Laptop + New supply != OK.

The new power module does not have enough power to "safely" support the old laptop.

MZr7