FirstWatt J2 - Page 49

ak4396 · 3rd May 2010, 01:18 PM

A Photocoupler.
Instead of the NPN Transistor, because the low Vgs of the Power-Jfet.

Zen Mod · 3rd May 2010, 01:36 PM

Quote:

Originally Posted by ak4396

The right direction?

value of source/drain resistors

LED positioning

emiter of opto bjt in wrong point

I'll say no more ......

no J2 Babelfish from Mighty ZM

ak4396 · 3rd May 2010, 04:14 PM

Zen Mod,

now my Brain is running hot ...

and her it is:

The way?

Thank You

Zen Mod · 04:22 PM

transistor part - better , but resistor values still not good , same as termination of LED part

........ and - you have few missing parts

google for nelson pass , optical bias , patent

ak4396 · 3rd May 2010, 04:35 PM

Sorry wrong Picture.

Now the right one:

I have count the Parts in the J2 Picture.
I would say its right (Power-R //).

I will read the Patent and come back :-)

spavleski · 3rd May 2010, 09:42 PM

Optocoupler should be galvanically separated

HVfanatic · 4th May 2010, 07:14 AM

I do not see any need for the optocoupler. Why not use a tl431 as Nelson does? maybe supply the tl431 by a CCS to ease its work? I even guess, thats not necessary, I would just put a 220uF cap across it to make it a stiff (whatever so adjusted) voltage offset...

The feedback connection would care for dc stability, and I guess, a 2SJ109 is preferable to single silicon devices...

But hopefully Nelson shares the secret, I have 2sJ109, semisouth ans 2sk170 waiting...

Dirk

yggdrasil · 4th May 2010, 09:05 AM

ak4396 - would you like to share your spice model of that precious device (sjep..) or point me in a useful direction.

Tea-Bag · 4th May 2010, 10:38 AM

Quote:

Originally Posted by HVfanatic

But hopefully Nelson shares the secret, I have 2sJ109, semisouth ans 2sk170 waiting...

Dirk

Well, that takes the fun out of cloning.

Nelson gave us enough details to start with, and 6moons photo's help. We now have some parts lying around, fire up the science lab and let's roll up our sleeves and go for it.

ak4396 · 4th May 2010, 12:44 PM

my LT-model
Not very good but at 1,5-2,5A not so bad.

3rd May 2010, 04:20 PM	#484
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	transistor part - better , but resistor values still not good , same as termination of LED part ........ and - you have few missing parts google for nelson pass , optical bias , patent __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; BAF Forum & Gallery;I'm dumb Last edited by Zen Mod; 3rd May 2010 at 04:22 PM.

3rd May 2010, 09:42 PM	#486
spavleski diyAudio Member Join Date: Aug 2005 Location: Belgrade	Optocoupler should be galvanically separated __________________ PSMLS CookBook by ZM

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3rd May 2010, 01:18 PM	#481
ak4396 diyAudio Member Join Date: Feb 2008	A Photocoupler. Instead of the NPN Transistor, because the low Vgs of the Power-Jfet.

4th May 2010, 07:14 AM	#487
HVfanatic diyAudio Member Join Date: Feb 2008	I do not see any need for the optocoupler. Why not use a tl431 as Nelson does? maybe supply the tl431 by a CCS to ease its work? I even guess, thats not necessary, I would just put a 220uF cap across it to make it a stiff (whatever so adjusted) voltage offset... The feedback connection would care for dc stability, and I guess, a 2SJ109 is preferable to single silicon devices... But hopefully Nelson shares the secret, I have 2sJ109, semisouth ans 2sk170 waiting... Dirk

4th May 2010, 09:05 AM	#488
yggdrasil diyAudio Member Join Date: Sep 2005	ak4396 - would you like to share your spice model of that precious device (sjep..) or point me in a useful direction.

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