Subject: Re: VaCUUm tube.
From: Repeating Decimal
References: <3de24a97.27328416@News.CIS.DFN.DE> <email@example.com>
NNTP-Posting-Date: Tue, 26 Nov 2002 19:08:42 GMT
Organization: AT&T Broadband
Date: Tue, 26 Nov 2002 19:08:42 GMT
in article firstname.lastname@example.org, Vico at
email@example.com wrote on 11/25/02 11:32 PM:
> Sorry for the spelling mistake.
> If FET can be used, then what about the transfer function?
> "Repeating Decimal" wrote in message
>> in article firstname.lastname@example.org, John Fields at
>> email@example.com wrote on 11/25/02 3:46 PM:
>>> On Mon, 25 Nov 2002 18:55:46 -0600, "Dave"
>>>> "Bob Peterson" wrote in message
>>>>> There used to be solid state substitutes for at least some commonly
>>>>> tubes. But I doubt if they are around anymore, as there just aren't
>>>>> many commonly used vacuum tubes anymore.
>>>> The only tube subsitutes I've heard of were plug-in replacements for
>> Except for impedance and consequent voltage difference, FET transistors
>> characteristics very similar to pentodes.
The FET will most likely have a higher transconductance, maybe more input
capacitance. It will also have a high outpute impedance in its linear
operational range. If you do not need a socket replacement, the same circuit
could probably be adapted, with some value changes to perform the same
function. You have to watch out, however, that your original circuit
application is tthat of a linear amplifier. All bets are off if you use
secondary screen emission such as in a transitorn operation.