ZM, In the iteration I got from you, J101, J102, J103 and J104 are stuffed, 4 SMD per channel.
Can you please confirm that I have to add R114 and R110 ? I'm also building with IRFP150 at M102 and M103.
I was confused by the markings for the test above to mattattnet's question (he says 4 jfets. I don't know if that means 2 devices or 4 devices)
Thanks
Can you please confirm that I have to add R114 and R110 ? I'm also building with IRFP150 at M102 and M103.
I was confused by the markings for the test above to mattattnet's question (he says 4 jfets. I don't know if that means 2 devices or 4 devices)
Thanks
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Have fun codyt! I'm about to start mine as well now that my Pearl 2 is finished. Just waiting on my Semisouths from jama via South America. 😎
ZM, I may have gone too far. The Semisouths are SEJP120R063 or double die 120's. I've read through other posts they should behave as 120's just better dissipation. Any thoughts on changes needed for the circuit with these or just bang em in?
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Nice!! I’m forcing myself to wait a day or so before I get going. Due to a completely unmerited act of generosity, I find myself with some SS parts - gotta take my time and savor this one 🙂
Of course ZM! Like IRFP150 = 2 X IRFP240, one SemiSouth SEJP120R063 = 2 X SEJP120R100. Oops. I mistyped earlier when I said double die 120’s. I meant double die 100’s.
frankly, I never look in data enough to compare these two, and get same conclusion as you ..... 🙂
if claimed xconductance is double , comparing to 100 , then 60 is doubled
in any case, both are working swell in Babelfish
in fact , I can say - whichever SJEP you have, just toss it in - only don't mix them 🙂
if claimed xconductance is double , comparing to 100 , then 60 is doubled
in any case, both are working swell in Babelfish
in fact , I can say - whichever SJEP you have, just toss it in - only don't mix them 🙂
Time to start matching. I made up some 5x5mm pcbs from the very generous EUVL’s (Patrick) gerber files for miniature 2sk2145 breakout boards. I soldered one up with gate and source connected to a 100ohm RN55. 9 volt battery is ready to go, although I may try a 12v switcher I have laying around.
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switcher is better, no voltage slide through time
put some RC in rail, say 100R and 10uF is enough
remember - both connected in parallel, threat them as one JFet
put some RC in rail, say 100R and 10uF is enough
remember - both connected in parallel, threat them as one JFet
I'll go with the switcher then for sure.
Good thought on the RC. I might have a few parts scattered around the bench for that. 😉
The breakout boards combine both sides as one. Handy little buggers.
Good thought on the RC. I might have a few parts scattered around the bench for that. 😉
The breakout boards combine both sides as one. Handy little buggers.
My matching rig. Curious to know others technique. I held the jfets on for 10 seconds then took the idss, but in some cases it seemed like this might not be long enough.
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you must wait for temp equilibrium - when reading is steady..... do not count time, look at display
no free lunch
I have fast socket thingie ........ and even with that , how fast you think that I'm doing batch of 50?
(having handy plate of Styrofoam , with 50 small holes in it)
ignore taster on thingie pic, later I put nice small relay and switch, so I can do other things while JFet is cooking, instead of keeping my finger on taster
edit- I'm testing proper Idss, no resistors in source or drain....... DMM connected as mAmeter in drain
no free lunch
I have fast socket thingie ........ and even with that , how fast you think that I'm doing batch of 50?
(having handy plate of Styrofoam , with 50 small holes in it)
ignore taster on thingie pic, later I put nice small relay and switch, so I can do other things while JFet is cooking, instead of keeping my finger on taster
edit- I'm testing proper Idss, no resistors in source or drain....... DMM connected as mAmeter in drain
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Thanks for the pointers ZM. Looks like I’m going to start over and go for equilibrium. Is there any risk to the jfets measuring true idss with no resistor?
> I'm testing proper Idss, no resistors in source or drain....... DMM connected as mAmeter in drain
So DMM as Ammeter does not use a current sensing resistor.
And the ammeter has a lower tempco than say a S102.
😉
Cheers,
Patrick
So DMM as Ammeter does not use a current sensing resistor.
And the ammeter has a lower tempco than say a S102.
😉
Cheers,
Patrick
If you've got good equipment of know quality (eg Fluke, Keysight Lab Bench Meters) it's easier just using the meter, and the accuracy is good enough.
If you've got a cheap crap multimeter of unknown quality then use a good current sense resistor.
I have decent tools, so I use a meter, same as ZM.
If you've got a cheap crap multimeter of unknown quality then use a good current sense resistor.
I have decent tools, so I use a meter, same as ZM.