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Old 09-02-2013, 03:37 PM   #1
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Default Question about power adapters, wattages, voltage and amps

I have a laptop that has two ratings: 18.5V/3.5 mA and 19.0V/4.74mA. This means the watts is 64.75 for the first rating and 90.06 for the second (P=IV)

I have a charger that is rated 19.5V/3.34mA, which means the power supplied is 65.13W

The wattage of the charger is close to that of the first rating of the laptop. Does that mean the charger will work? Or is it something to do with the voltage and amp rating?

Also, how is it that the laptop can take both ratings of 64.75W and 90.06W?
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Old 09-02-2013, 03:49 PM   #2
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Default Re: Question about power adapters, wattages, voltage and amps

It will not work because the voltage is different. The voltage must match.
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Old 09-02-2013, 04:01 PM   #3
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Default Re: Question about power adapters, wattages, voltage and amps

Your laptop should only have 1 voltage/amperage rating. Can you post a picture of where you see the 2 ratings?

It is important that the charger's voltage matches EXACTLY but the current rating of the charger should be equal to or greater than the rating for the laptop. You also need to make sure that the polarity of the DC plug is correct.
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Old 09-02-2013, 07:33 PM   #4
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Default Re: Question about power adapters, wattages, voltage and amps

strollin,

I have attached the pictures. The laptop rating is under the battery, bu then again maybe Im reading the wrong thing. Maybe its 19V and 4.74mA and the line on top is the input specs. Still will a 19.5V/3.5mA work with my laptop
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File Type: jpg 20130902_173317.jpg (43.2 KB, 3 views)
File Type: jpg 20130902_173332.jpg (106.9 KB, 5 views)
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Old 09-03-2013, 09:25 AM   #5
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Default Re: Question about power adapters, wattages, voltage and amps

That's strange that there are 2 ratings, haven't seen that before. I think the key is that the top rating has US next to it which seems to mean that the rating is 18.5V/3.5 mA in the US and 19.0V/4.74mA outside the US.

The 19.5V adapter may work but it could cause problems such as overheating and it could even damage your laptop. The laptop probably has regulation circuitry in it that can handle higher/lower voltages but why take chances on an expensive item such as your laptop? You should be able to find an adapter with the correct voltage for $20 or so.
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Old 09-03-2013, 09:47 AM   #6
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Default Re: Question about power adapters, wattages, voltage and amps

strollin, okay I know I can find another adapter for about 20 or so, I was just hoping I could use this one. I know that current wise,l if the adapter can supply more or equal to the rating, things will work as the laptop takes what it needs. But as to voltage, do you know what variance is acceptable?
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Old 09-03-2013, 11:52 AM   #7
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Default Re: Question about power adapters, wattages, voltage and amps

No, I don't know what variance is acceptable. You'd need to contact the laptop mfr support people and ask them but I'd be willing to bet they will simply attempt to sell you a new adapter at a higher cost then you could find one elsewhere.
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Old 09-03-2013, 04:07 PM   #8
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Default Re: Question about power adapters, wattages, voltage and amps

strollin,

thanks for the info
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