Power Supply compatability

Discussion in 'General Electronics Chat' started by Gdrumm, Mar 17, 2015.

  1. Gdrumm

    Thread Starter Distinguished Member

    Aug 29, 2008
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    36
    I bought a Toshiba Satellite A75-S2112 laptop on Ebay for $5.00, but it has no power supply.
    The specs call for the power supply to be 19v, 90w, 6.3 amp.
    On Ebay, those cost around $25.00

    I found an advertised A75 power supply, 19v, 90w, with only 4.74 amps for $6.99, with free shipping.

    Will that one work?

    I sent the seller a compatibility question, but it says it may take up to 2 days to get a reply.

    I thought you guys might be able to give me a quicker reply.

    Thanks,
    Gary
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,548
    2,373
    90 watts @ 19v = 4.74a?
    Max.
     
  3. Gdrumm

    Thread Starter Distinguished Member

    Aug 29, 2008
    684
    36
    Got it now, thanks,
    watts=amps x volts
    So 19 volts x 6.3 amps would be 119 watts.
    I did find one with 120 watts for $16.00.

    Gary
     
  4. wayneh

    Expert

    Sep 9, 2010
    12,126
    3,048
    As a general answer to your question, I would not feel comfortable going down in rating for a power supply. In my experience, the manufacturers cut it a little too close as it is and going to larger rating sometimes solves problems. Inadequate power can cause the computer to throw up a complaint, and those those little bricks can get awfully hot when taxed. Adobe Flash should be paying a carbon tax for all the extra power it requires of the world's computers!
     
  5. BR-549

    Well-Known Member

    Sep 22, 2013
    1,995
    388
    Hi Gary.
    You're not buying a power supply....you are buying a battery charger.

    The 6.99 unit will be fine.
     
  6. crutschow

    Expert

    Mar 14, 2008
    13,016
    3,235
    The supply has to provide not just charging current but also power to run the computer when it is on and the supply is plugged in.
     
  7. wayneh

    Expert

    Sep 9, 2010
    12,126
    3,048
    And it needs to run the computer when the battery is removed.
     
  8. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,540
    1,251
    And it has to have the correct connector. In my experience this is the hardest part about buying a replacement laptop supply online.

    Check the label on the bottom of the laptop. The current listed there is the correct value to both run the laptop and charge the battery at a reasonable rate. The battery will charge faster if the laptop is off, and slower if you use a charger with a lower current rating.

    ak
     
  9. Gdrumm

    Thread Starter Distinguished Member

    Aug 29, 2008
    684
    36
    This being a $5.00 laptop, I don't expect the battery to hold a charge.

    I do have a couple of old power supplys laying around that may meet the 19v, 90 watt, 6.3 amp requirements.

    But of course, the plug must fit.

    I have other Toshiba laptops as well, and they are all plugged the same (with various power ratings however).

    I may try one of those first, before I spend any more money (on a project Laptop).

    Great input from you guys, I always learn something here.

    I appreciate everyones input.

    Gary
     
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