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  1. Replies
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    Closed: Re: Minimum trace thickness

    Current density through the track will have no effect on magnetic radiation, only on voltage drop and track heating.
    Magnetic coupling depends on total current flow, frequency, and enclosed loop...
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    Closed: Re: Spiral inductor simulation

    If its electromagnetic radiation, only the magnetic H field is going to induce anything into a coil.

    I don't know of any particular software, but a pancake coil is just like any other coil if you...
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    Closed: Re: Peltier Cooler Temperature

    Thanks, a lot Chemelec.

    Those curves do not show maximum cooling capacity at zero volts, you are being sarcastic. Try to help people, and getting stomped on is why I come to this Forum less and...
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    Closed: Re: Peltier Cooler Temperature

    That has not been my experience.

    And the curves in the data sheet for that actual device suggest otherwise as well.

    137272
  5. Closed: Re: Need help with generating *INTERLACED* mode VGA signals

    Have to agree with Tricky Dickey.
    If you already know all the correct answers why bother asking the question ?
  6. Closed: Re: Need help with generating *INTERLACED* mode VGA signals

    137209
    See slide 42.
    https://www.slideshare.net/MadhumitaTamhane/black-and-white-tv-fundamentals

    You will need to alternate between even and odd fields by displacing the horizontal sync half a...
  7. Closed: Re: How to determine minimum AWG for re-woud transformer

    That would certainly work.
    The only disadvantage might be slightly degraded output voltage regulation because the total primary resistance has now doubled.
    But if free stuff can be put to good...
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    Closed: Re: Peltier Cooler Temperature

    Try reducing your voltage below 12v.
    You will find a voltage and current where the cold side temperature reaches a minimum.
    Either more or less power than that reduces the performance.
  9. Closed: Re: How to determine minimum AWG for re-woud transformer

    What these really need are more turns of thinner copper wire (to fit into the available space) on the primary to reduce the flux level.

    Just judge the size of the iron core. It looks more like a...
  10. Closed: Re: How to determine minimum AWG for re-woud transformer

    Just be aware that these transformers work well into magnetic saturation and have aluminium windings.
    Absolute minimum iron and aluminium (which is a lot cheaper than copper).
    These things are...
  11. Closed: Re: Need advice about obtaining more RF experience

    I suppose a lot depends on the facilities and test equipment you have access to.
    Its all changed so dramatically over the last few decades since I was a student.
    Its no longer possible to just...
  12. Closed: Re: Relationship between Q factor and the coupling factor of two wireless coils

    Not sure about a Bode plot, but the amplitude versus frequency effect of over coupling is certainly very readily visible on a spectrum analyser.

    The main thing is that with very loose coupling...
  13. Closed: Re: Peltier element controller method, 20Amps bidirectional current

    Yes indeed !
    Switching between heating and cooling with 50/50% duty cycle is certainly not going to give a net thermal effect of zero.

    At zero you want everything switched completely off.
    Then...
  14. Closed: Re: i need help for measuring a speed of an object

    What are you measuring the speed of, a bullet or a snail ?
  15. [SOLVED]Closed: Re: Inductance and resistance of solid wire vs Litz wire

    Litz is nice, but it can be difficult to terminate well. Every individual strand needs to be stripped and tinned. If not carried out with fanatical care the results can be disappointing. This can be...
  16. Closed: Re: i need help for measuring a speed of an object

    This sounds like homework.

    You will need to do three things.

    1/ Measure the time interval over a known distance exactly as you suggest.

    2/ Use the time interval number obtained to program...
  17. [SOLVED]Closed: Re: Inductance and resistance of solid wire vs Litz wire

    Yup.
    Treez has nailed it.
  18. Closed: Re: Can Transformer Toroid core be used as EMI core

    Should work well, because with a common mode choke the dc cancels out, leaving just the inductive impedance free from any magnetic saturation effect.
  19. Closed: Re: Relationship between Q factor and the coupling factor of two wireless coils

    Easy P. is quite correct.

    What happens at great distance is that coupling is weak and the two tuned circuits can be peaked independently, but energy coupling is poor because of the distance.

    As...
  20. Closed: Re: Peltier element controller method, 20Amps bidirectional current

    I suggest you hook up your peltier first with just an an adjustable dc bench power supply.

    Get it working in the cooling mode, and find the optimum dc input power for maximum cooling effect.
    You...
  21. Closed: Re: Peltier element controller method, 20Amps bidirectional current

    That application note is pretty good.
    Could be an interesting new experience doing a Bode plot down to millihertz frequencies with a data logger.
  22. Closed: Re: Peltier element controller method, 20Amps bidirectional current

    An integral feedback loop corrects slower and slower as the error decreases, so that is not a problem.
    I used a very basic Analog loop and liner power control stage.
    If I was going to use PWM,...
  23. Closed: Re: Peltier element controller method, 20Amps bidirectional current

    Full bridge would be the way to go, with one of the upper right and left pair dc switched for polarity control, (P channel ?) and just one lower device PWM'd at very low frequency, perhaps at only a...
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    Closed: Re: PWM signal noise problem

    The spike may not really be there, it could be a problem with your probe, or how/where your probe is grounded.
    Try connecting the tip of your probe to ground and see if that spike is still there....
  25. Closed: Re: Peltier element controller method, 20Amps bidirectional current

    Treez, these Peltier cells are PN junctions, they don't have fixed resistance but act like lossy resistive diodes in the forward direction.

    Next thing you should know is peak efficiency is about...
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