Help building a boost converter

Discussion in 'The Projects Forum' started by Darkraver, Apr 2, 2012.

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  1. Darkraver

    Thread Starter New Member

    Apr 2, 2012
    Hey guys,

    I'm trying to build a boost converter to charge up the capacitors for a school project, but I don't seem to have very much success. I'm trying to boost 12v up to 750V, which requires a duty of 98.5% if my calculations are right. With the use of some online calculators (namely: and) I got an inductor value of 42mH, and have a 100mH inductor plugged into my boost converter to test. The capacitors I have plugged into the output are two 100uF caps rated at 450V in series. (The final capacitors I need to charge are 4050uF rated at 800V) But when I measure the output, I get only 0.655V.

    I can't seem to figure out why I am not getting any useful values, can any of you help?

  2. Darkraver

    Thread Starter New Member

    Apr 2, 2012
  3. rfredel

    New Member

    Jan 23, 2011

    the problem is, that your boost converter has not enough power to charge the capacitor.
    An emty capacitor is like a short circuit for your supply.

    It's better to use a converter with a transformer so you have more Power to charge the capacitor.
    I'll look for a circuit, that was used in a Photoflashlight. I must draw this diagram, because I have built it 40 years ago.
    After finishing the drawing I'll post it.



    PS: Sorry if my English is too bad.
  4. bertus


    Apr 5, 2008

    I am closing this thread as it violates AAC policy and/or safety issues.

    6. Restricted topics. The following topics are regularly raised however are considered “off-topic” at all times and will results in Your thread being closed without question:
    Any kind of over-unity devices and systems
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