10 Jul
2007
10 Jul
'07
6:56 a.m.
From: woodelf <bfranchuk at jetnet.ab.ca>
dwight elvey wrote:
Hi
Not that I know of. JFETs only come in the depletion mode.
This would make powering on harder. MOSFETs can be made
both depletion and enhancement because the gate is isolated.
The current technology is to use enhancement type MOSFETS.
Besides, the combination JFETs I talked about do not work
on the same principle as a TD, they just act like one in that
they have a nice negative resistance region. Real TDs will
oscillate at even higher frequencies.
TDs had the limiting problem that they were current devises.
They never turned off. So, even if they made logic, the power
consumed would limit the density.
Right now, we are at the power density limits for uP's. We can
build smaller ones and put more circuits on a chip but we've
hit the limits of power density. We get smaller improvements
If you really want them to act like a TD, place a
resistor in parallel
to give the final slope. It doesn't make them any better at doing
fun things but is closer the a real TD.
Dwight
But with a ka-zillion tunnel diodes you can build the fastest
computer ever. Well that was what all the hype was about in the
early 60's.
Did anyone ever use Junction Fets in computer logic?
from lower K insulation on wiring but power is now the
wall.
Dwight
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