[ARC5] FETs and ---odes

[Bill Cromwell]

W7EKB said:

Hello, Dennis:

Yes. It may ACT like a pentode, but it still has only three 
leads....like a tri-----ode...so, when replacing a multigrid-tube 
with one, which lead goes where?

Or does one have to use more than one FET to equivalate (a new word?) 
a tetr-ode or a pent-ode?

IMHO, in circuits which originally have tetrodes or pentodes, the 
circuit would have to be redesigned.

It should be reasonably obvious where to connect which lead if one 
were using an FET to replace a tri-----ode.

Voltages, of course, would be a different matter.

Ken W7EKB

Hi Ken,

The word has already been used and it's "synthesize". There are
conniving plans on the internet to use two FETs to replace the obsolete
and now expensive dual gate mosfet's. I think W7ZOI is one of the
publishers.

Wes and others suggest that plugging in fet's and bipolar transistors
where a tube goes is a poor idea. The tubesters or fetrons would have to
have some other components like resistors to stand a chance and they
would also have to be "adjusted" or tweaked to work in different
applications. Not impossible but maybe not worth the trouble. It is more
reasonable to just modify an existing tube circuit to use transistors
instead of tubes. That is heresy for some and to me it's still not worth
the trouble. I could probably build a complete solid state radio for the
same amount of effort - even if it doesn't LOOK as cool.

Back at the original post - our friend already has a modified radio and
would be adding a solid state BFO that would be designed form the start
as a solid state BFO. The BFO that should have been in his radio was
removed by somebody else once upon a time and other tube circuits
replaced it for other functions. Now he wants a BFO back. There is no
place to plug a tubester or fetron into his radio. The pattern is full
<g>.

73,

Bill  KU8H