high low cut out

Discussion in 'The Projects Forum' started by speeed_777, Mar 21, 2009.

  1. speeed_777

    Thread Starter Active Member

    Oct 5, 2008
    54
    0
    as my question is time consuming,plz don't ignore it,help me as fast as possible:
    first plz take look at this circuit(which automatic swith off supply for high and low range)
    http://www.electronic-circuits-diagrams.com/psimages/powersuppliesckt4.shtml
    now the problem is ckt don't work.I think something wrong in it! :
    here for ic1:555,we are taking sampling from output pin of 7809.which will be always constant,then how we are taking sampling of input A.C. voltage??
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
    Hello,

    It looks like they have forgotten someting at the collector of transistor 1.

    [​IMG]

    The low cutout is not connected to anything now.

    Greetings,
    Bertus
     
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