Left two are mystery as Tokin parts don’t have depressed ring at the bottom.
It’s a miracle that they are working after beauty treatment (electroplating) as this includes high voltage and conductive bath. Last year I bought two similar and got two shiny but completely burned out parts. Of course, seller had pictures of real THF-51 on the AliExpress page, but was shipping out junk. I managed to get my money back.
It’s a miracle that they are working after beauty treatment (electroplating) as this includes high voltage and conductive bath. Last year I bought two similar and got two shiny but completely burned out parts. Of course, seller had pictures of real THF-51 on the AliExpress page, but was shipping out junk. I managed to get my money back.
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Tomoaki on eBay has the read deal. Last year he sent to me a box of 10 that I curve traced and sent back. Since then he has acquired access to a curve tracer. I just bought a quad of his matched curve traced parts. It looks like he does a very good job of matching based on the curves and not just one point. I am looking forward to the master's creation for these parts.
Thanks for the comments!
Yeah, it was tricky, because on the day of order, there was a picture with original looking SITs.
After some day, they changed the picture, just as what I've got now.
At least, these have a plain baseplate. 😉
These weren't inexpensive, I think, I rightly expected the originality of the items.
I've saved the pictures, and I will start a dispute to money back.
Yeah, it was tricky, because on the day of order, there was a picture with original looking SITs.
After some day, they changed the picture, just as what I've got now.
At least, these have a plain baseplate. 😉
These weren't inexpensive, I think, I rightly expected the originality of the items.
I've saved the pictures, and I will start a dispute to money back.
Attachments
Like other audiophiles I have affection for symmetry, but I draw the line at
audio nervosa
Looking at the data on these parts I see that the low Drain impedance of SITs
makes it more important that it would be for regular sorts of fets, and so matching
is a bit more complicated.
On the plus side, the load line adjustments you can make will often compensate
for that.
In the end, if you want a really good match you insert the SIT into an example of
the kind of circuit you want to use, and be prepared to adjust each instance.
audio nervosa
Looking at the data on these parts I see that the low Drain impedance of SITs
makes it more important that it would be for regular sorts of fets, and so matching
is a bit more complicated.
On the plus side, the load line adjustments you can make will often compensate
for that.
In the end, if you want a really good match you insert the SIT into an example of
the kind of circuit you want to use, and be prepared to adjust each instance.
O.K..
Chinese guy can't understand my problem, that I don't know what I've got from him.
Or just he don't want to understand it.
Well, other things.
Papa taught me, that JFETs are symmetrical devices, it isn't matter how you use them, S-G-D or D-G-S.
Curve tracer shows it nicely,
I thinking about, how it is with SITs,
Locky-z's curve tracer autodetect say it is N-JFET.
So I swapped S-D, and got the following result.
On the left, there is two SITs with the appropriate connection, on the right, these two with swapped S-D.
Must have to say, I like more, what is on the right side.
Any thoughts about my sillyness?
Chinese guy can't understand my problem, that I don't know what I've got from him.
Or just he don't want to understand it.
Well, other things.
Papa taught me, that JFETs are symmetrical devices, it isn't matter how you use them, S-G-D or D-G-S.
Curve tracer shows it nicely,
I thinking about, how it is with SITs,
Locky-z's curve tracer autodetect say it is N-JFET.
So I swapped S-D, and got the following result.
On the left, there is two SITs with the appropriate connection, on the right, these two with swapped S-D.
Must have to say, I like more, what is on the right side.
Any thoughts about my sillyness?
Attachments
I’m thinking that the software for the automatic testing circuits simply does not have reference data for the ancient SIT devices we discuss here.
I’m looking back in the several, long, threads for the circuits for examining these devices. I’m hoping to be in the third wave of the Sony VFET kits, which looks like won’t happen until this fall. So I decided I would work up a Frankentracer, and search, some more, for NPs testing circuit. I was not smart enough to print that out last time I ran across it. I have some SITs, including some I bought in the past that I am skeptical of.
I’m looking back in the several, long, threads for the circuits for examining these devices. I’m hoping to be in the third wave of the Sony VFET kits, which looks like won’t happen until this fall. So I decided I would work up a Frankentracer, and search, some more, for NPs testing circuit. I was not smart enough to print that out last time I ran across it. I have some SITs, including some I bought in the past that I am skeptical of.
Earthquake damaged the factory as I understand it, halting the production, which was not restarted.
Edit earthquake in 2011, but not sure when the last run of these devices was performed. You might recall the nuclear plant issues.
Edit earthquake in 2011, but not sure when the last run of these devices was performed. You might recall the nuclear plant issues.
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Apart from this, curve traces, what I've got with normal and reversed S-D connections, seems to be real for me.
Your results are correct. SITs (all those that I’ve tested) measure differently when you swap the d-s connections. The auto detect id of the part as a njfet is merely a ballpark - anyway the curvetracer software doesn’t have SIT as a type of device.
Don't assume that these parts are really symmetrical, even if they trace so, as it is unlikely that the dissipation and soa character are the same.