Message	Date	From	Subject
15435	2019-09-05 11:29:40	zmetzing	Transistor linearity
So, as I researched a way to replace the 2N4416 (and -A suffixes) in older schematics, I came across some interesting reading material from Chris Trask (N7ZWY). He has written a paper which includes transistor curve tracings for several common (at the time) JFETs, such as the MPF102, U/J310, 2N3819, BF244, etc. He claims that linearity can be predicted from the Ids spacing between Vgs steps, and the general "flatness" or ideal current source across Vds. You can find his paper here: http://home.earthlink.net/~christrask/ Search the page for "JFET Transistor Evaluation". I'd like to hear opinions on the validity of his assertions, if anyone has done some investigation. I plan to duplicate his curve tracings using modern-package equivalents (MMBF4416, MMBFJ310, etc.). --- Zach N0ZGO

So, as I researched a way to replace the 2N4416 (and -A suffixes) in older schematics, I came across some interesting reading material from Chris Trask (N7ZWY). He has written a paper which includes transistor curve tracings for several common (at the time) JFETs, such as the MPF102, U/J310, 2N3819, BF244, etc. He claims that linearity can be predicted from the Ids spacing between Vgs steps, and the general "flatness" or ideal current source across Vds.

You can find his paper here:

Search the page for "JFET Transistor Evaluation".

I'd like to hear opinions on the validity of his assertions, if anyone has done some investigation. I plan to duplicate his curve tracings using modern-package equivalents (MMBF4416, MMBFJ310, etc.).

--- Zach

N0ZGO