lykkedk said:I stumbled around the net, to find an explanation and to figure out, what Xl, inductance (mH) means to appr. coilsize / magnetwire thickness. And i didnen't succeded
I don't know how much current that will flow in drek inductor, and i don't know howto calculate the F3 of some inductor.
I have the possibillity to use magnetwire in the range 0,25 ~ 1,00mm, but if DCrestiance ain't the problem, i rather use thin, than thick.
I could make inductor's in size between ~80mH - 200mH, but what i really like is to understand, and to calculate the perfect size for the circuit.
Hope some (Magura, ZenMod etc...) can help me out!
Jesper.
The perfect size does not exist AFAIK. You will always find yourself dealing with trade-offs.
The F3 is also a matter of the impedance of the load, so I took the liberty to experiment my way through, rather than calculating this.
The inductor will see 250mA, so you could use real thin wire. DCR then comes into play. How big loss are you willing to accept?
When doing this the hard way, it turned out that you can get away with 2*80mH, the math pointed to a somewhat bigger figure.
So, as written above, plug the numbers into the calculator I gave you the link for earlier in this thread (EDIT: the link I am going to give you later in this thread) , say any wire between 0.1 and 0.5mm will do (trade-offs again), just go wind the inductor, and see what it brings to the table.
Unhappy with the result- then start making experiments to become happy
Magura
Magura, is this inductor calculator a DOS program ?
The site dosen't seem to work theese day's, but i found the program (i think carefull please! - might be fraud)
http://www.users.on.net/~audiosoft/inductor.exe
I can't make it work... my windosbox simulated under linux can't run it.
Well... I just got my 6pack beer-hands on two trols of 0,335mm (~AWG28) wire ... nearly 2*10kg ... well they will gonna cost me a bit through i think!
So i calculated some inductor-size's. All with innerdia 35mm, and lenght 15mm (15+15 for dual inductor, for Drek) :
2*80Mh, 1206 turn's, 35 Ohm
2*100Mh, 1327 turn's, 40 Ohm
2*120Mh, 1435 turn's, 44 Ohm
2*140Mh, 1531 turn's, 48 Ohm
I might just try, as Magura purposed, but it might be usefull, if i could calculate the F3 freq. to awoid nasty thing's ... (still don't know howto) What should i go for ???
Jesper.
The site dosen't seem to work theese day's, but i found the program (i think carefull please! - might be fraud)
http://www.users.on.net/~audiosoft/inductor.exe
I can't make it work... my windosbox simulated under linux can't run it.
Well... I just got my 6pack beer-hands on two trols of 0,335mm (~AWG28) wire ... nearly 2*10kg ... well they will gonna cost me a bit through i think!
So i calculated some inductor-size's. All with innerdia 35mm, and lenght 15mm (15+15 for dual inductor, for Drek) :
2*80Mh, 1206 turn's, 35 Ohm
2*100Mh, 1327 turn's, 40 Ohm
2*120Mh, 1435 turn's, 44 Ohm
2*140Mh, 1531 turn's, 48 Ohm
I might just try, as Magura purposed, but it might be usefull, if i could calculate the F3 freq. to awoid nasty thing's ... (still don't know howto) What should i go for ???
Jesper.
lykkedk said:
......
Jesper.(sry. i am no pro ..)
........
me neither ......
let Papa tells ya :
http://www.diyaudio.com/forums/showthread.php?postid=1227215#post1227215
you can look at first page of that thread for schematic
tip:
look at "apparent resistance" of one output mosfet
edit :
xconductance is A/V ;
but V/A =Ohm
so - often xconductance is written in mho , which is nothing else than
reversed ohm , or 1/ohm
lykkedk said:
soo Choky you tell me, that xconductance is A/V(Opposite of Ohm) and that V/A = Ohm(part of ohms law), which leads me to just ... nothing! About the result the spreadsheet gives me ... what does plate resistance have to do with that ?
xconductance of Jfet Boz 2SK170 is ( as Papa sez) 1/50 ohms ~ and according to datasheets - 20 to 22mS ...... (same thing written backwards)
according to data sheets , xconductance of irf9610 is ?
so - just recalculate what's apparent resistance of 9610 and you'll know what to include as plate resistance in your xls file ......
hehe
or just use 2x80mH ......... that's plenty ........
tip :
plate = drain in that case ; just analogy , off course
lykkedk said:Yes
The trickquistion, is just to tricky for me...
Jesper.
if 170 have xconductance of 22mS , means that his apparent impedance is 1/0,022 ~ 46 Ohms
if 9610 have xconductance of 0,8S , means that his apparent impedance is 1/0,8 ~ 1,25 Ohms
anyway - knowing from da toob world real parameters are these ones measured in working point , you can't be sure in exact values of xconductance without looking at real graphs ;
in any case 9610 have enough low internal impedance , so your chosen 2x80mH choke is good enough ..........
edit :
don't forget to include source resistance in calcs ...... 10E
edit edit :
in case you have woolly
bass - just decrease these source resistors and re-bias da drek
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