Power Supply Board Ripple

Discussion in 'General Electronics Chat' started by Baskaran Manoharan, Apr 20, 2016.

  1. Baskaran Manoharan

    Thread Starter New Member

    Apr 18, 2016
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    Hi,
    I am using 19.5V/4.5A power supply, measured the Ripple Voltage across the load It is almost 140mv ,After 10min again i measured Ripple voltage on same load its reduced to 40mV How is it?
     
  2. #12

    Expert

    Nov 30, 2010
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    I would guess that the load current diminished after 10 minutes.
     
  3. wayneh

    Expert

    Sep 9, 2010
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    Putting it another way, the question cannot be answered unless/until the load is known when the ripple measurement is made.
     
  4. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
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    Switching or linear supply?

    How much warmer was the power supply after 10 minutes?

    ak
     
  5. Baskaran Manoharan

    Thread Starter New Member

    Apr 18, 2016
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    0
    I am using 19.5V/4.5A(Laptop adapter) switching power supply only,For Load purpose i am connecting 100ohm/10W wire wound resistor,The load is only getting more heat,For ur reference i attached ripple waveform details
     
  6. BillB3857

    AAC Fanatic!

    Feb 28, 2009
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    353
    Has the power supply been out of usage for a long time before these tests? If so, the output filter caps may have "deformed" and after a while, "reformed" to a proper value. Electrolytics can sometimes behave like that. It is not uncommon to connect replacement electrolytics that have been in storage to a slowly increasing volgtage up to near the rated voltage of the cap. This allows the electro-chemical reaction needed to form the dielectric barrier.
     
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