Title: Do power adaptors automatically adjust current and voltage?
Tags: laptop;power-supply;power
Question: I purchased a new power adaptor (19.5 V, 3.33 A, 65 W) for my Compaq Presario v3000 laptop, as replacement for the old one (18.5, 3.5 A, 65 W). It is listed as compatible with my laptop model.
Does the new adaptor automatically adjust based on current drawn?
Comment: I would suggest checking the label on the laptop itself and see what voltage and current it specifies. You should try to match that voltage exactly. And you want an adapter that can supply at least as much current as the laptop says it needs.


Here is another answer: The new adapter will output 19.5V, or very nearly that, regardless of the current the laptop draws, unless it exceeds the supply's maximum output. It's possible that 19.5V is inside the safe input range for your laptop, and it's possible that 3.33A is sufficient. It's also possible that 19.5V is dangerously high for your laptop or that 3.33A is insufficient. But assuming whoever listed it as compatible knew what they were doing, then the ranges must safely overlap.

Here is another answer: Sounds strange to me that the voltage isn't right.
Voltage has to be absolutely right. I tend to see it specified to 1 decimal place, so, it should be right to 1dp. Use the specified voltage.
When it comes to amps, the device uses what it needs. So the power supply's Amps need to be >= what the device needs.
I guess it's possible that when it's as high as 18V then 1V might not make or break it but that's a wild guess to say that and I wouldn't be keen on trying it. You're meant to use the correct voltage.

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