[sdiy] Does Source = Drain???

[David G. Dixon]

> Horowitz and Hill has a pretty good chapter (Ch 3) on FETs, which
> addresses
> many of your questions.  That's the place to start for an advanced
> hobbyist
> level of understanding.
> 
> As one example, they write: "... FETs ... are nearly symmetrical, but the
> gate-drain capacitance is usually designed to be less than the gate-source
> capacitance." (What Antti said.)

Found it!  So, I went looking for evidence from datasheets.

2N5485 (an RF JFET) has 5pF input capacitance Ciss, and 2pF output
capacitance Coss.  Do these refer to the source and the drain, respectively?
Incidentally, this datasheet says the source and drain are interchangeable.
Go figure!

All the other datasheets I had on hand only listed Ciss, as does Table 3.1
in Horowitz and Hill.  Does this imply that Coss is the same, or that nobody
in their right mind would ever be stupid enough to hook the damn things up
backwards, and therefore Coss is irrelevant?