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  • EEVblog #659 – Medical Plugpack Teardown

    Posted on September 2nd, 2014 EEVblog 6 comments

    What’s inside an IEC60601-1 medical class 5V mains DC-DC plugpack?
    What is the difference between PCB clearance and creepage?
    A German FRIWO 5V FW7555M/05 brand medical grade isolation unit vs a cheap Wun Hung Lo consumer brand.
    Also a comparative look at transformer construction.

    Datasheets & Links:
    Rubycon Caps
    CD 263 Caps.
    Vishay Optocouplers

    Forum HERE

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    • Zsola

      That winding around the transformer is for EMI-compliance, it is the shielding of the core. I have never seen this kind of wire, ususally copper foil is used (e.g. in ATX PSUs). Maybe they “did the homework” in this case. Dave, as I remember, you did a teardown where this kind of pulse-transformers had nice shielding. I have found this in the teardown of the Marconi RF Gen.

      • Dave Jones

        Yeah, has to be it, and yes they must have done their homework that it was adequate enough to save the cost.

    • maelli01

      Jianghai caps are Chinese. But they have a cooperation/licence with Hitachi AIC.
      Not one hung low

      • RGtx

        If your not au fait with the chinese language, try their American site:

    • max-bit

      Poland won against Australia in volleyball !!!
      Greetings to the quarterback from Australia !!! Thomas Edgar !!! not bad !!!

    • blipton

      So in order to reduce EMI, it common to place a capacitor between between the main ac side and the isolated 2nd side?