Power Adaptor Compatability

I own a Studio 1557 that uses an adaptor with 19.5V/4.62A output. My wife owns an Inspiron 6000 with an adaptor with 19.5V3.34A output. The jack sizes are identical. Can we use each other's adaptors? My assumption is that I might get away with both but that my wife might damage her laptop with my adaptor due to the higher output.

However, since assumptions are the mother of all f*ck ups, I'd prefer sound advice from someone more knowledgeable on these issues!

 

You have it in reverse. Your wife will likely get away with it but you probably won't.

That's because voltage is the force which is pumped out of the jack, whereas the current is the electrical charge contained in that force.

Think of your adapter as a water pump. The voltage is the water pressure. Your laptop needs to be able to cope with that much water pressure or it will be damaged. The current is the volume of water the pump can supply. You can use anything up to the rated supply, but if you demand more water than the pump can supply, it will overheat and maybe burn out.

Your Studio 1557 adapter uses 19.5V to supply up to 4.62A current, whereas your wifes adapter can only supply up to 3.34A of current.
Her adapter would likely get very very hot trying to supply your power hungry 1557 with the 4A+ it will try and draw.
Whereas you adapter will easily meet the demands of her Inspiron which will only need 3Aish of the 4.62A yours can supply.

That said, I'd still advise you don't swap around as there are other factors such as jack polarity which can be different.

 

Thanks for the excellent, in-depth and easy-to-understand reply. Your analogy was quite apt as I am a fireman!

 

No probs, happy to help.

 

Regarding polarity - all Dell power bricks made since the Pentium M era have the same form factor and pinout (save for a couple oddballs like the B130), so as long as your adapter meets your laptop's power requirements, you can generally use any old Dell adapter without any problems.