[sdiy] Example of NTE confusion..

[Bob Weigel]

Here, I just looked up an equivelent for the 2SC3853 for an amp I 
repaired.  I got the original parts first off because the NTE390 I 
figured might be the same since ECG390 was listed for it as a 
replacement in my Sams software....had the wrong kind of case.  No 
plastic isolation for the screw so rather than even mess with it I just 
ordered the original part not knowing what other hassle it might save me.
    But after getting the amp up working again and biasing, I looked up 
the spec to see if maybe this was the exact match transistor.  The 
NTE390 is listed at 100V 10A.  The original part I thought it might 
replace is listed as 120V 6A.  Hmmm.  Current never makes up for lacking 
voltage.  If you exceed the voltage limit by much at all for long at all 
you blow the device usually.  It's always uncertain how much overvoltage 
a piece of silicon can take.  If it's been overvoltaged period you 
replace the device rather than risk a future breakdown.
     Anyway just had that handy example I thought I'd toss out since we 
were talking about it the other day.  It's possible NTE downgraded some 
of the numbers in the system to parts that were available/cheaper and 
covered most of the bases I suppose. Maybe that's why the sams software 
only listed the ECG part on that particular one?   I find many pages 
saying the same thing I've always thought...that they used the same 
numbering system (which I would think "system" includes...ahem..which 
device spec is correlated to that number?? duhhhh. :-)  Oh the things 
people do with GRAMMAR these days....otherwise they would have just said 
"use the same numbers" and left off 'system'..right?  )  Here's one of 
the pages : http://www.logwell.com/tech/components/ECG_NTE_SK.html
    But anyway, I've found many things like that in the past.  Or maybe 
I just keep running across the same one and forget. :-) No I think they 
were for sure some different ones.  Heheh. -Bob

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