AVR-Chat

why a new power source? i'm using some PC sources, if
this are modified you can use in any output you need.

in the net you have some modification to this to make
a comminucation power source, general this are about
13,8V and 15 Amps or more.

The only thing you need to do is change the secondary
wending of the power transformer and chage the value
of the reference resistor of the TL494.

For you aplication notes this, the 5V outlet have 15
or 20 Amps and the 12V section have 5 or less.

If you don't need much than a few amperes i'm think
only changing the 12V wending you can have 24V and 2
or 3 amperes.

this power sources have about 300W to 450Watts.

Best Regards
Frank

 --- Russell Shaw <rjshaw@netspace.net.au> escribió: 
> 
> Kathy Quinlan wrote:
> > Hi all,
> > 
> > I am resurecting an old project atm and I need to
> build a powersupply, 
> > it will take in an average of 120Vdc (from ~100 -
> 160Vdc) and provide 
> > regulated 24V and 5V rails. Total wattage around
> 60W.
> > 
> > I chose the uc3842 SMPS controller as the
> regulator. I am trying to work 
> > out the design of the transformer.
> > 
> > I am using a ferroxcube ETD34/17/11 with the 3C90
> cores. I have worked 
> > the example in the philips UC3842 appnote ( 
> > moon.feld.cvut.cz/hw/philips/acrobat/8014.pdf )
> Using the values of the 
> > EC35 core with the 3C81 core (it says a 3C8 core
> but I can find no info 
> > and believe the last digit is missing)
> > 
> > I am getting very strange results in my
> calculations and as transformer 
> > theory is not my area, I need some help lol
> > 
> > TIA
> > 
> > Kat.
> 
> 99% of the energy is stored in the air gap and for a
> flyback
> supply you must have one. Then you must know the
> core cross-sectional
> area, the saturation flux density (0.3 Tesla is
> usual), length
> of the primary pulse, and flyback voltage across the
> transistor.
>  From that, you can determine the turns-per-volt.
> However, thermal
> problems limit how small the transformer can be, and
> winding
> capacitance limits how high the frequency can be.
> 
> 
>  
> Yahoo! Groups Links
> 
> 
>     AVR-Chat-unsubscribe@yahoogroups.com
> 
>  
> 
> 
> 
>  


	

	
		
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