Dual Gate Mosfets (more)

[Phil]

Yes Joe, I was surprised to discover their disappearance a few years ago. Depending on the frequency you want to work at, two regular MOSFETs in series (drain to source) will often do the job.

Phil M1GWZ


On 5 Nov 2012, at 15:17, wb5mmb wrote:

> Just put leads on them. http://www.hamelectronicsmagazine.com/dgmosmod.html
>     Sandy
>    WB5MMB
> 
> 
> At 07:24 AM 11/5/2012, Gerald Wolczanski wrote:
>> See (from the QRP-l forum GD3YEO):
>> I have been reading all the responses to my request for a 40673 and am
>> overwhelmed. I had determined from all the responses including yours
>> that the BF998 was what I wanted. I then looked at SMT to conventional
>> leaded part solutions and came up with an adapter board of sorts from
>> Capital Advanced Technologies which is handled by Digikey. This little
>> adapter board adapts the SOT143 package to a SIP package and they only
>> cost less than $1.50 ea in single quanity. The BF998 are 14 cents each
>> 
>> Another ham just suggests flipping the BF998 upside down and bending the
>> tabs.
>> 
>> Most posters suggests the BF998 is actually BETTER than the 40673.
>> W7ZOi suggests that when the MOSFET mixer is implemented properly, it
>> can offer very good performance.  It would certainly run rings around
>> the NE602 family of devices, which ought to be outlawed IMHO.
>> 
>> Jerry
>> 
>> 
>> On Sun, 2012-11-04 at 20:35 -0700, Joseph Bento wrote:
>> > When did dual gate mosfets such as the 40673 or 3N211 enter the
>> > unobtanium category?  I managed to find a source tonight for a few at
>> > reasonable prices - $3.00ea, but these are parts that used to sell for
>> > pennies.  Now it seems they are going the way of tunnel diodes,
>> > germanium transistors, and other semiconductors of old.
>> >
>> > I always found a dual gate mosfet to be a simple way to cobble together
>> > a quick mixer.  Guess I'm going to have to learn new methods.
>> >
>> > Joe, N6DGY
>> >
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