UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > General Vintage Technology > Components and Circuits

Notices

Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

Closed Thread
 
Thread Tools
Old 24th Jun 2020, 3:36 pm   #1
Malcolm G6ANZ
Octode
 
Malcolm G6ANZ's Avatar
 
Join Date: Feb 2006
Location: Bristol, UK.
Posts: 1,030
Default 2N3819 pinout

Looking at a 2n3819 FET for a 90MHz preamp for my old Cossor. There is a difference of opinion on the internet about the pin out arrangement.
With the flat uppermost and the leads towards you, some give the arrangement ,reading left to right, as D,G,S and others give it as S,G,D.
The Fairchild data sheet gives the DSG arrangement so this is what I shall be using. Though why other sites give a different pinout I don't know.

Malcolm
Malcolm G6ANZ is offline  
Old 24th Jun 2020, 3:50 pm   #2
Humber888
Heptode
 
Humber888's Avatar
 
Join Date: Jul 2012
Location: Bromley, London, UK.
Posts: 702
Default Re: 2N3819 pinout

IIRC the FET is pretty much symmetrical, so S and D are effectively the same. Have a look at this old thread: https://www.vintage-radio.net/forum/...d.php?p=909109.
Humber888 is offline  
Old 24th Jun 2020, 4:08 pm   #3
Malcolm G6ANZ
Octode
 
Malcolm G6ANZ's Avatar
 
Join Date: Feb 2006
Location: Bristol, UK.
Posts: 1,030
Default Re: 2N3819 pinout

That thread answers my question.
Thanks
Malcolm G6ANZ is offline  
Old 24th Jun 2020, 4:14 pm   #4
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,800
Default Re: 2N3819 pinout

There are some tricks with symmetrical FETs.

In SSB transceivers where filters and IF structures are operated in one direction for receive and the opposite direction for transmit, it's usual to have lots of switches reversing the inputs and outputs of amplifiers. With symmetrical FETs the positive feed for the drain can be swapped to the source, and the amplifier amplifies in the reverse direction.

Whoever thought of that one was a very smart cookie!

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is online now  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 11:41 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.