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Minimum current draw of AC to DC converter at no load

Discussion in 'General Electronics Discussion' started by bobdxcool, Aug 22, 2015.

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  1. bobdxcool


    Mar 9, 2012
    I wanted to know if there is a minimum current draw on the AC to DC converters from the AC source when it is connected to an input voltage of 120V (60Hz), when no load is connected at the output of the converter ? Is this current draw constant ?

    For example, if we consider this converter from progressive

    If we consider the PD 9180, would there be any current draw from the AC source for this converter ?
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    Jan 21, 2010
    There will always be some minimum if the device is powered on. However this minimum could vary from almost immeasurable to a significant percentage of the full load current.

    Unless it's in the specifications, I would either ask the manufacturer or get one and measure it.
  3. davenn

    davenn Moderator

    Sep 5, 2009
    hi Bob

    generally yes there is a very small current maybe in the order of a few mA for a wallwart switching regulator plugpack
    and most likely increases as the SMPS increases in its ratings

    to find out for any given SMPS, you would have to ask the specific manufacturer

    there is a cool device called Kill-A-Watt a small unit that plugs into the wall outlet and then your device plugs into it and it displays Wattage etc being used

  4. Colin Mitchell

    Colin Mitchell

    Aug 31, 2014
    Some of them have a special circuit to reduce the idle current to 10mA or less and it looks for something connected to the output.
    Some 4kW inverters drop to 10mA.
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