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  1. [SOLVED]Closed: Re: Iron sheet laminated gapped core inductor variation

    Figure of post #7 shows that relative permeability varies a lot with applied field strength (proportional to current). Lower field strenght gives lower permeability giving lower flux density.

    - -...
  2. Closed: Re: Bypass dc signal which is accompanied with a low frequency sinusoidal signal

    Now depends on the settling time you need. For settling time = 0.5 seconds, a 16nF cap and 10 Meg resistor. Do not push too much the settling time, otherwise you will attenuate your AC signal.
  3. [SOLVED]Closed: Re: Iron sheet laminated gapped core inductor variation

    How low? I understand that at higher than 0.5T most materials can start to saturate, but using a very low range of magnetic flux density also makes it vary, as you just saw from the above posts...
    ...
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    Closed: Re: parasitic coil capacitance from frequency

    Another way is to apply fast rising edge step voltage and measure the ringing.
  5. [SOLVED]Closed: Re: Iron sheet laminated gapped core inductor variation

    Also mine and yes it is dominated by the gap. In fact, that is how I computed it. The inductance variation is due to low excitation value provided by the LCR ( in the mA range).

    gap length = 0.23...
  6. [SOLVED]Closed: Re: Iron sheet laminated gapped core inductor variation

    Of course there is a mistake. That was the whole point of this thread. I computed theoretical inductance for high "H" and hence "mu_r", but did not tested it correctly (at few mV RMS, the current is...
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    [SOLVED]Closed: Re: calculating capacitance of transistor gates

    It includes the gate driver's resistance and transistor's internal resistance as well.
  8. [SOLVED]Closed: Re: Iron sheet laminated gapped core inductor variation

    Of course they are not the same. FvM showed typical iron core material to let me see how much the permeability varies with such material, but still not exactly mine (M400-50A).

    Sure. Or another...
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    [SOLVED]Closed: Re: calculating capacitance of transistor gates

    Peak current into gate of transistor is simply V_driver/Rgate. No need for any capacitance value.
  10. [SOLVED]Closed: Re: Iron sheet laminated gapped core inductor variation

    Sure. Or assume you are in the high µ_r region and neglect core recultance: Rcore<<Rair gap. Under this assumption, the overall path has a reluctance: Roverall path under above assumption & E+I core...
  11. [SOLVED]Closed: Re: Iron sheet laminated gapped core inductor variation

    Inductance measurement done in the 0.5 T range and does not vary with changes in voltage (maintaining high magnetic density flux).

    Thank you all for your help.
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    [SOLVED]Closed: Re: calculating capacitance of transistor gates

    The effective input capacitance is calculated as in post #1. You have capacitance curves in the datasheet.
  13. [SOLVED]Closed: Re: Iron sheet laminated gapped core inductor variation

    Yes. With very low current, might not get enough magnetic field strength ("H"), hence low mu_R... Next will try variations using high current.

    - - - Updated - - -


    You presume correctly. I am...
  14. [SOLVED]Closed: Re: Iron sheet laminated gapped core inductor variation

    Not going to.. sorry, because I know accuracy is affected by voltage applied due to different currents in the connections. Furthermore, I am using the "series measurement test". Not parallel one, as...
  15. [SOLVED]Closed: Iron sheet laminated gapped core inductor variation

    Hello everyone,

    I have a gapped (few mm of air gap) inductor wound around the E+I sheets of a laminated core Power Core M400-50A.

    The problem that I see is that the inductance when measured...
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    [SOLVED]Closed: Re: Injection XFMR source level

    Thanks FvM for your help.

    Here are the results.

    XFMR designed as follows:
    Core material: VAC T60006-L2050-W516
    Windings: bifilar wound 50 turns, AWG 19


    Measurements using a sweep from...
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    Closed: Re: RF PCB design in altium

    That is too big a constraint. Controlled line impedance starts at more than 1/4 wavelenght.. Why do you use that number ?
  18. [SOLVED]Closed: Re: can flux from switching inductors cause interference

    Actually it is good. The closer the ground plane to the inductor, the less interference it will produce due to more compact magnetic field lines.
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    [SOLVED]Closed: Re: Injection XFMR source level

    Sure. 24 mVrms for 10 ohms load.

    As you say, once you know they use a 50 ohm VNA, it is easily calculable the source signal level. I do not get your "no sense statement" or "ambiguous...
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    [SOLVED]Closed: Re: Injection XFMR source level

    Why does not ? Why would you want load and source matching for no more than 10 MHz ?


    I do not want to buy a 500$ XFMR, so I wound one myself. I want to compare mine with their, so I want to...
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    [SOLVED]Closed: Injection XFMR source level

    Hello everyone,

    What is the source signal level the B-WIT 100 injection XFMR gain response was characterized with ?

    I think it is 0.27V of amplitude (i.e. ~0.2 V RMS) if source is 50 ohms, but...
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    [SOLVED]Closed: Re: Negative VCO transfer function

    Alright. That was it. I was missing the triangle wave of the XOR phase detector. Since kVCO<0, the PLL will lock in the [Π, 2*Π] interval where kPD<0.
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    [SOLVED]Closed: Re: Negative VCO transfer function

    Well yes it does. As I mentioned, the loop gain is phase shifted with additional 180º making it unstable.

    PLL is implemented as: XOR phase detector kpd>0 --> LPF --> kVCO<0 (for XR2206) can you...
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    [SOLVED]Closed: Re: Negative VCO transfer function

    What if the PLL is working with an XOR gate ?
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    [SOLVED]Closed: Negative VCO transfer function

    Hello everyone,

    The VCO XR2206 shows at page 11 that the kVCO is negative. That introduces 180º phase in the transfer function of a PLL making it unstable. How can PLLs built around XR2206 work ?...
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