In message <CANnsUMFiEqEOs9Si0pke8F-9R34KDT+DGL8kOgkA3oN15_WQ-g@...>, dated Mon, 23 Dec 2013, Chris Maness <chris@...> writes:
A friend of mind sites the miller effect as being the reason for f_o shift. I will have to read up to see if this is indeed the case.
Miller effect is feedback via the anode-to-control grid capacitance. It can depend on B+ voltage if the stage gain changes with B+ voltage. I doubt that it does very much in a JFET, operating in 'FET saturation' (pentode region), which is not the same as bipolar 'saturation' (bottomed). And the drain-gate capacitance is much smaller anyway than in some tubes (you need to take external strays into account because of the physical size difference).
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OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk
Nondum ex silvis sumus
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
