What is the key rule for ensuring that a different laptop charger can work with a laptop?
I've always been wary since a few years ago when I used a laptop charger from a different brand laptop, not looking at the charger's electrical specifications, and it ruined my battery, essentially turning the laptop into an A/C only computer.
My current laptop is a Toshiba, as is my smaller one, and the chargers for each have the same voltage and amperage. I thus assume that they would be safely interchangeable.
However, do voltage and amperage have to be the same to be safe? I would suspect that a higher voltage would wreck the laptop or battery, as with a higher amperage. I don't have a great knowledge of power, however.
These are my guesses; could you please verify each and elaborate? I'd like to learn why something is good or bad. Do both the input and output specs have to match the criteria? Or is only the output important?
- Higher voltage & higher amperage: bad
- Higher voltage & same amperage: bad
- Higher voltage & low amperage: bad
- Same voltage & higher amperage: bad
- Same voltage & same amperage: good
- Same voltage & lower amperage: good, but slower charge
- Lower voltage & higher amperage: bad
- Lower voltage & same amperage: good, but less power and slower charge
- Lower voltage & lower amperage: good, but less power and slower charge
(PS: I suppose the same would apply to phones, etc?)