Let’s say that my laptop computer needs 50 volts or 200 volts (I don’t know what it actually uses.)
Now, if I plug my laptop into a 110-volt outlet (this is on an airplane, so I have no other alternative power outlets available; it’s either the 110v or nothing), will my power cord be capable of moderating the electricity to the desired level? Or will my laptop suffer damage from having too much or too little electricity fed into it?
As you can tell, I’m a complete novice and ignorant when it comes to electrical matters. I don’t even know if my question is legit, but there it is - does power outlet supply matter to computers, and can a power cord make it all turn out good - i.e., ensure that the laptop gets the right voltage regardless of whether the socket is 70, 110, 180 or 200 volts?
All modern laptop computers use an external power supply.
With very few exceptions, these are designed to accept any voltage standard across the world.
Just look on the adapter - it will tell you what the acceptable voltage range is.
Your computer will definitely need a different voltage and current from what’s available in any AC slot. (In fact, it probably needs DC, not AC.) The brick on your power cord is responsible for transforming what’s available at the outlet into what it needs.
Most modern power bricks are smart enough to take a range of different juices. For instance, I looked at a couple of mine, and they both listed "INPUT: 100-240 V, 50-60 Hz. America and Canada use 120V, and Great Britain uses 230V, but my computer power bricks could work with either, as long as I have the right adaptor plug.
The little brick thing that’s part of your laptop power adapter transforms external voltages into whatever your laptop needs. It usually has a range on it, like 100-240v, which is what you can plug it into. It then converts whatever that voltage is into whatever your laptop needs, so your laptop sees the same voltage no matter what you’re plugged into. Most laptop chargers these days can be used internationally, maybe with a change of adapter head.
Just as a point of interest, the lowest mains electricity voltage you’ll find anywhere in the world is 100 V, in Japan. The highest is 240.
As others have said, most modern laptop power supplies will work with a range of 100-240 V. If yours covers that range then it’ll work anywhere in the world.
A related question I’ve had is about the output of the transformer (power supply). It seems most laptops run on 19 volts, but I assume different machines will draw a different amount of current. Some power supplies I’ve had say, for example, “OUTPUT: 15-24 Vdc.” Does this mean that that the laptop could operate on, lets say, 17 volts, or does that mean that the voltage actually varies as the machine operates?
Output *voltage *of a power supply is fixed, and the computer will draw only as much *current *as needed. I could see at least three reasons why a power supply might have the voltage labeled as you indicate.
The supply company makes the same supply with different voltage versions. Usually they will have a checkbox by the actual voltage used, or a label indicating the actual voltage.
The supply is a generic laptop supply that has the output voltage controlled either by a switch, or by proprietary adapters that it uses for the various laptop brands.
The supply uses multiple power lines of different voltages, possibly for better filtering. In that case instead of a round connector, it would be a squarish connector with four or more contacts.
I believe these do actually vary their voltage… anyway they understand the laptop has a regulator (…well in front of or in the form of, a switch mode power supply to produce all the different voltages required,efficiently … ) and there for the small over voltage or under voltage is no problem.
I can’t recall having seen a power supply with a range labeled like that and especially so broad. Which supply said that? However, it is not at all uncommon for a supply to output something quite different from the nominal voltage.
Some older laptop supplies had several outputs so you might have, say, 20VDC @4amps AND 12VDC @1amp but I haven’t seen one like this in years.
It would need a more complicated connector, for starters.
This is one label on the back of one. IIRC, I got it at some electronics supply store.
Well, it has a base connector which can have different jacks attached, so it can be connected to various machine power inputs. But is the output going to be the same no matter which connector you attach? Or does it automatically produces a different voltage depending on which machine you connect it to? I mean, does a power supply just consistently output 90w, and then the voltage will adjust according to the current that gets drawn from it?
The voltage is determined by circuitry in the tips. It will only output one voltage per tip type.
The wattage figure is the maximum safe amount that the power supply can provide. Wattage is current (Amps) times voltage (Volts). A laptop computer will use a set voltage, but the current draw will vary depending on what it is doing.
ETA: Again. The voltage output of a power supply is meant to be constant and stable. The current draw (Amps) of a device attached to the power supply is what varies. Electronics are built to work with a specific voltage.
Yes, I know that so I was curious about the “variable” voltage, but it hadn’t occurred to me that the tips themselves would have their own circuitry. That must mean that devices with that specific jack (and diameter, etc.) must always run on the same voltage, right? (Are there standards about power supply jacks?) I thought that just about all laptops run on 19v, but now I see some are lower, so it’s designed for those, too.
Nope, there is no standard. Look at the list of tips I quoted. You have to make sure you are using the right voltage tip for your device as different voltages may be the same size.
