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  1. Closed: Re: Passing both DC and pulses through a toroid?

    for a very large toroid; the first single turn with 5V applied will have its current ramping up at 5/Lpr amps per sec, the flux in the core will ramp in proportion to the current, any sec...
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    Closed: Re: Buck converter vs buck-boost converter

    you are referring to a cascaded buck + boost, 2 converters in one ...
  3. Closed: Re: How to calculate transformer winding losses

    it is part of the overall losses and does not lend itself to exact calculation - frequency makes a difference as does the shape of the currents flowing - no doubt the data sheet figures are...
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    Closed: Re: Buck converter vs buck-boost converter

    LT8705 is a lot of bits if you just want a low power converter

    @ asdf44; I think the point is made - with good layout capA is not required ...
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    Closed: Re: Buck converter vs buck-boost converter

    cap A is there by virtue of B & C, i.e. cap A can be deleted if B & C are there ...
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    Closed: Re: Buck converter vs buck-boost converter

    try searching: www.google.com/search?client=firefox-b-d&q=buck+boost+converter&sa=X&ved=2ahUKEwiSjcXO7aLlAhXITX0KHd0TChUQ1QIoAHoECAoQAQ&biw=1366&bih=626

    156083

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    a...
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    [SOLVED]Closed: Re: HEI primary current duration

    interestingly that IGBT has 120 ohm internal gate resistor to guarantee a slower turn on / off - it also has 1.25V Von drop at 6A ... which will subtract from the 12V available
  8. Closed: Re: Generation of 4 Phase Shifted clock Signals

    CD4015B should do it (?) 4 stage shift register - dual -

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    sorry - I missed post #7 - at 2.5MHz it is futile to use discretes because of the delays introduced ...
  9. [SOLVED]Closed: Re: Calculate Capacitance Value from Smith Chart

    respectfully - even if there is loads of resistance as there is here - 50 ohm in fact - the Smith chart tells you the reactive impedance AND the resistive impedance hence 50-j77 ohm ...
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    Closed: Re: Buck converter vs buck-boost converter

    respectfully - you not bucking or boosting from input to output... a common ground is also often assumed which this ckt cannot supply
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    [SOLVED]Closed: Re: Wiring of DC fans in Series

    a cheap buck converter to give to 12V for the fans is looking better and better ...
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    Closed: Re: Buck converter vs buck-boost converter

    you may get the same total losses as only one fet to control and one o/p diode - plus far easier control - less time to build and get going ...
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    [SOLVED]Closed: Re: Wiring of DC fans in Series

    Q4 is not needed - Q3 will dissipate, Ifan * 15V so be careful there ...
  14. Closed: Re: Mains leaking currents causing problems in my house

    A PC psu should be designed to at least 2.5kV ac phase to o/p's if not it is a very bad PC to own

    a dish washer could be run thru an isolation Tx - but an electric cooker would...
  15. [SOLVED]Closed: Re: Calculate Capacitance Value from Smith Chart

    he reactive part is 77.16 ohms, this is the sum of the Xc & XL, at 205MHz it is basically all capacitive so yes = Xc
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    Closed: Re: Buck converter vs buck-boost converter

    A flyback is also a buck-boost ( the original in fact )

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    as is a Sepic
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    [SOLVED]Closed: Re: Wiring of DC fans in Series

    R's are fine - but extra power draw / loss and no guarantee of sharing at power up where fans can and do draw more than 5x the run current - and its pretty pulsed too...!

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  18. [SOLVED]Closed: Re: Calculate Capacitance Value from Smith Chart

    the Smith chart is for a specific 10pF cap, that is clue #1, it is not explicitly shown on the Smith chart, but the 77 ohm at 205MHz gives you 10pF, presumably at very high freq the series L ...
  19. Closed: Re: Mains leaking currents causing problems in my house

    You could go around cutting out all the Y caps ( RFI caps that go from phase & neutral to "earth" ) inside the appliances that have them - this should stop you getting a boot off your PC - ...
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    [SOLVED]Closed: Re: Wiring of DC fans in Series

    a 5W 16V zener across each fan will be the way to go, else a buck converter to 15V to run both of them in //.
  21. Closed: Re: Generation of 4 Phase Shifted clock Signals

    CMOS gate parts can do this easily @ 2.5MHZ look up the CD4000 series - there should be a shift register type part that will do it in 16 or 14 pins ...
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    Closed: Re: Buck converter vs buck-boost converter

    boost converter usually has low side drive to the fet which is easier, buck converter needs a level shift driver or a P channel fet - more parts will affect efficiency - but either can...
  23. [SOLVED]Closed: Re: Calculate Capacitance Value from Smith Chart

    The smith chart for that cap shows you that at 205MHz it is 10pF ( 77 ohm ) and 50 ohm resistive ...
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    Closed: Re: Filter Cutoff Frequency

    the noise flows from right to left - ideally the CM caps need to be on the LHS ( left had side ) in order to get a CM LC filter - this can be undone if the primary mosfets are heatsunk to...
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    Closed: Re: Bridge diode thermal problem

    bigger caps = shorter current pulse = higher rms current draw = more heating in diodes and wires ...

    45V, 10A schottky a good idea if pk volts out of Tx are < 35V ... 5W zener...
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