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Class D Switching Power Amplifiers and Power D/A conversion 

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25th October 2012, 08:20 AM  #2721  
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Join Date: Jul 2007

Quote:
guyz the clear pdf artwork for the 4K5 have fun with real tested high power class d 

25th October 2012, 09:24 AM  #2722 
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Join Date: Dec 2003
Location: Nottingham UK

An ETD29 core with a 1mm gap in the centre leg only will have an inductance factor (Al) of close to 125nH.
The equation for the total inductance (where N is the number of turns) is N^2 * Al. So 17 turns will give you roughly 35uH. If you are adding a 1mm gap to an ungapped core set (so the gap is in all legs), the Al will be much lower of course. 
25th October 2012, 01:29 PM  #2723  
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Join Date: Jul 2007

Quote:
so gap in all legs it will come to how many turns to make 35uh Last edited by stewin; 25th October 2012 at 01:52 PM. 

25th October 2012, 01:57 PM  #2724 
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Join Date: Dec 2003
Location: Nottingham UK

It is not a parameter that is defined in the data for the cores. This is the time to buy a low cost inductance meter perhaps?
When I get an unknown core, I wind a known number of turns on, measure the inductance and then determine Al. I then can use this value to calculate the mumber of turns needed for any required inductance on that particular core. 
25th October 2012, 02:01 PM  #2725 
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25th October 2012, 03:52 PM  #2726 
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Join Date: Oct 2009

irs 3000 coil inductance(uh) ?

25th October 2012, 04:02 PM  #2727 
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Join Date: Aug 2008
Location: KERALA

Hi stewin,
i used 40T .85mm core 1mm gap all (@70uH) fsw=250KHz cap=2.5uF/250V, cool quite MOSFET IRFP250N with resistor 39 Ohm. Regards MANOJ 
25th October 2012, 04:36 PM  #2728  
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Join Date: Aug 2008
Location: KERALA

Quote:
use 28T for 35uH regards MANOJ 

25th October 2012, 05:58 PM  #2729 
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Join Date: Jul 2007


25th October 2012, 08:07 PM  #2730 
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Join Date: Jul 2007

the component side side of pcb
thanks to ht forum Amplificador ClasseD  Página 74 have all the fun with high power amps " seek and you shall find " Last edited by stewin; 25th October 2012 at 08:14 PM. 
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