The only time that I used a semiconductor curve tracer recently was for the Blowtorch Mosfets. There, you could really see differences, because Gm seems to vary, without any obvious reason, but with Idss, or Beta, it is not the easiest measurement, where you can make a simple circuit to measure these, and compare with a simple meter.
Complementary pairs are usually purposely constructed, thus usually by
a single manufacturer with (perhaps) related part numbers.
Thanks hitsware,
That is what I would assume but didn't know if at times others have found complements that were from different manufacturers that just happen to work well together.
That is what I would assume but didn't know if at times others have found complements that were from different manufacturers that just happen to work well together.
You can buy a new, built curve tracer for use with a PC... see eBay or thread on test and measuremnt forum. I think it is cheap at approximately $225 USD.
Thx-RNMarsh
JC... today I sold a painting at auction in Bay Area. Got more than 100 times what I had paid for the painting back in 1994. Got to go shopping now 🙂
Need ideas on what to spend it on...
THx-RNMarsh
Need ideas on what to spend it on...
THx-RNMarsh
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Good for you, Richard. Unfortunately, I lost anything like that in the firestorm of 1991. You could try some Jack Bybee stuff. '-)
It would be tough to build a semiconductor curve tracer from scratch. Too many switches. Like Richard said, it might be possible to find a kit that will go with a computer screen, or you can buy a Tektronix used. That is what I have.
This is good for 2 lead devices :
What (equally simple) needs be added for the 3rd lead ?
What (equally simple) needs be added for the 3rd lead ?
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Or these for free.....
A webbing of cured standard roofing/bathroom silicone between the coils damps them.
A heavy slab (an offcut of standard kitchen top granite/marble etc) suspended on springs makes for a very cost effective equipment platform (zero cost !).
Placing another slab on top of line level gear makes for a very high mass assembly that is nicely inert.
Mileage may vary according to donor car.
Dan.
..... a Blowtorch . 😛
More seriously, what test gear or audio gear don't you have ????.
Dan.
Triodes are more linear however unless you have SABLE ( stash acquisition beyond life expectancy ) stock then you go down the road of ultra unabtanium . This lends them to Diyers for one off types . Myself unless I have 6 to 12 of a date code and type then I stay away from them . For design of and building of salable product Triodes are far less viable than fets. If your doing it for you self and have 40 or 50 of one date code tube then go for it.
Typical "complementary" NPN/PNP
I just grabbed a couple of graphs for some Toshiba devices sold as complements of eachother. This result is typical of many if not most, Beta/Va quite different as well as saturation characteristics. Absolute Vbe's also all over the place. You can match beta's at one Vce that's about it.
I just grabbed a couple of graphs for some Toshiba devices sold as complements of eachother. This result is typical of many if not most, Beta/Va quite different as well as saturation characteristics. Absolute Vbe's also all over the place. You can match beta's at one Vce that's about it.
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Well to be fair, a good portion of that is due to an air gapped transformer with DC current flowing through its primary.
se
Thanks ! Every thing has it limits operating them outside of there comfort zone and using transformer to drive a low z speaker when a high z speaker matches better is a problem. I did not say they where perfect nor that they could do every thing for everybody . Rightness of fit for the task .
Now yer talkin'. 😀
But power tubes aside, small signal triodes are quite linear.
se
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