Choice of dual transistor for input stage, how much current ?

[Bernhard]

In simulation the BC550C was 0,01mA better, but a better? ccs makes a noticable difference, see picture.

 

[Mark Johnson]

@mirlo - thank you!! Yes it's because the bulk mobility in the base is highest when the base is n-doped and that makes PNPs the winner. btw I ultimately wound up teaching EE371 twice and EE313 once; Over the years Bruce W. asked me to teach those, giving Mark and Boris a much needed breather.



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