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The Answer For The AVR Question

By on November 19, 2008

Few days ago i posted a question on “Could Automatic Voltage Regulator (AVR) use as an isolation transformer?”

The answer is YES if the AVR that you bought stated that it has the isolation transformer feature and make sure that the AVR has higher VA to support the load. If you power up an equipment from a low output VA of AVR, it might burnt up the transformer inside the AVR.



  1. aurelio

    October 5, 2012 at 5:25 am

    Hi Jestine,
    Thank you for answering regarding the right isolation transformer.
    By the way, This is now my first attempt to repair an smps. The fuse blown but the bridge rect. is good and I don't know how to test the power IC indicating  "top 223y" cause its not in the ebook testing ecomponents. Can you tell me how to test this IC?
    Thank you and hoping your reply

    • Jestine Yong

      October 5, 2012 at 11:09 pm

      Hi Aurelio,

      The power ic can't be tested using multimeter to check if it is ok or not. But if you have the ic datasheet you can check the vcc and ground pin to see if it is shorted or not. You can try remove the power ic and retest to see if the fuse will blow again or not. You may also use the series light bulb trick to save the fuse. Google for series light bulb trick and you will get what I mean.



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