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Old 12th Jan 2017, 5:17 pm   #27
Ian - G4JQT
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Join Date: Jun 2004
Location: Reading/Fakenham, UK.
Posts: 1,320
Default Re: 2N3819 Mosfet

Quote:
Originally Posted by crackle View Post
So is that a fact the 2N3819 JFET can be used either way round, with equal efficiency, the only pin which needs to be specific is the gate.
Wow that does seem strange.

The project I am working on is a Minimod TX, Phil G4SPZ has been sent me a photo of one he made so I will be fitting the JFET in the same way.
The positive supply is fed to the JFET by the red and green wire.
My first MiniMods used the 2N3819 FET, and yes, the pinouts are confusing! The gate is in the centre and as has been stated, many FETs are more or less functionally symmetrical.

I changed the FET in later versions for a BF256 as it had a tighter spec - I had some 2N3819s that just were not very good. But beware - the BF256 gate is at one end of the three leads not in the centre.

Ian
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