laptop adapter cord size

Discussion in 'General Electronics Chat' started by anhnha, Sep 13, 2014.

  1. anhnha

    Thread Starter Well-Known Member

    Apr 19, 2012
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    As you see in the picture, the cord size at the input of the laptop adapter is bigger than the one at the output.
    What is the reason for this? I guessed it is relating to current capacity but my friend said that is not the case.
    He said that the current flowing through the output cord is also higher than the input one.
    Is that wrong?


    [​IMG]
     
  2. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    Input: 100-240 volts @ 1-0.5 amperes
    Output: 16 volts @ 4.5 amperes.

    Your friend is right.
     
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  3. anhnha

    Thread Starter Well-Known Member

    Apr 19, 2012
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    So, what is the meaning of these parameters?
    I consider the adapter is a power supply so 16V is output voltage and 4.5A is current capacity of the source but how about 100-240 volts @ 1-0.5A?
    Is it the current capacity of wall socket?
    And the cord size?
     
  4. MrChips

    Moderator

    Oct 2, 2009
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    You also have to consider electrical breakdown at the higher voltage,100-240VAC.

    The input power cords are standardized items that must meet international safety standards. These are stock components that are supplied in huge quantities. The OEM (original equipment manufacturer) does not have much say in the matter.
     
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  5. anhnha

    Thread Starter Well-Known Member

    Apr 19, 2012
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    So, the bigger cord is to avoid electrical breakdown. What are other reasons?
     
  6. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    -More durable.
    -Can carry more current.
    -More expansive.
     
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  7. anhnha

    Thread Starter Well-Known Member

    Apr 19, 2012
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    Thanks, what do you mean by "more expansive"?
     
  8. MrChips

    Moderator

    Oct 2, 2009
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    You will notice that the AC mains power cord can be unplugged from the adapter. That is so that the manufacturer of the computer equipment can supply the same adapter for international markets and all they have to change is the AC mains power cord to suit the local AC wall socket required.
     
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  9. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    The input cord must meet many safety criteria - including being stepped on or pulled from the walk by the cord (instead of the plug). All without catching your house on fire or exterminating the user! Safety, safety, safety! The copper adds most of the tensile strength of the cord assembly.

    The risk of failure is too high to make 120/220 V power cords for fractional amp equipment out of copper of the minimum wire size for their amperage.
     
    Last edited: Sep 13, 2014
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  10. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    Also. The input cord is 3 wires. Output cord is only 2 wires.
     
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  11. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Now that I zoom in, it looks like low-voltage output wire is 18 gauge (probably the same as the input mains voltage cord). Read the small white letters on the cord. It should tell you wire size and insulation voltage rating.

    The mains voltage cable has thicker insulation to add to tensile strength and wear from abrasion, bending and compression.
     
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  12. anhnha

    Thread Starter Well-Known Member

    Apr 19, 2012
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    I read and understood the concept for safety in the forum tutorial. However, here where I live doesn't use the third wire, mostly.
     
  13. anhnha

    Thread Starter Well-Known Member

    Apr 19, 2012
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    Actually, that is not my adapter. Mine is Dell one and it doesn't have any information on the wire. I will take a look at that adapter tomorrow.
     
  14. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Sometimes it is hard to see, small letters/numbers impressed in the cord during molding (cladding) or other times it is printed. Look closely, it would be odd to have nothing on a cord - no matter where in the world it was to be sold. It just costs more to do things differently for each region when it could all be done the same way.
     
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  15. anhnha

    Thread Starter Well-Known Member

    Apr 19, 2012
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    Yes, you are right. I just found out.

    [​IMG]

    [​IMG]
     
  16. GopherT

    AAC Fanatic!

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    It should also be written on the length of the cord and repeated every 50 cm or so.
     
  17. anhnha

    Thread Starter Well-Known Member

    Apr 19, 2012
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    It is not clear now. I can only read something like this:
    LFC-3R...KTL SUO1001-4002 227 IEC52 3G-0.75mm LONGWELL 2010
     
  18. BardBashir

    New Member

    Sep 4, 2015
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    Yes your friend is right. You can also see on the adapter that the specifications of the Input and Output are mentioned at there. You can notice from there that the Output current is high than the Input Current.
     
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