EMRFD Message Archive 7628

Message	Date	From	Subject
7628	2012-07-23 16:08:40	wheverly1@verizon...	Transistor substitute
The 40673 used to be a popular transistor in many projects. Unfortunately as far as I can tell it is no longer readily available. Does anyone know of a sustitute that is availale? Bill H. W3AOQ
7631	2012-07-23 16:34:01	Alexandre Veiga	Re: Transistor substitute
Bill,   I use BF982 in my projects with the same results.   73,  Alex  PY4EU ________________________________ De: "wheverly1@verizon.net" <wheverly1@verizon.net> Para: emrfd@yahoogroups.com Enviadas: Domingo, 22 de Julho de 2012 17:07 Assunto: [emrfd] Transistor substitute The 40673 used to be a popular transistor in many projects. Unfortunately as far as I can tell it is no longer readily available. Does anyone know of a sustitute that is availale? Bill H. W3AOQ ------------------------------------ Yahoo! Groups Links [Non-text portions of this message have been removed]
7632	2012-07-23 20:07:21	Thomas S. Knutsen	Re: Transistor substitute
That device pops up here as an dual gate mosfet, probably made before I was born... I have recently done a lot of experementing with the BF99* series of dual gate mosfets and they are quite remarkable. With the BF992 I get consistent 1dB NF at approx 20-23dB gain with an IIP3 of 0dBm. This is managed on 50MHz, 70MHz and 144MHz without any problems with an simlar design that is in EMRFD fig 6.35. I have also done some testings with the BF998 and BF991, and BF998 have loads of gain, but you need to be carefull to avoid it singing opera at UHF (oscillation). Short leads and a couple of ferite beds helps a lot. An NF of 1.5 with either one should be possible. Observe that the BF998 have an Vds of 12V while BF991 and BF992 have Vds of 20V. All of this devices are SMD, but easy to use since they just have 4 legs. I like to cut an layout on 2 sided pcb for it and then just solder the circuit around that, or use all SMD components and cut squares as I see fit. If you realy need long legged devices, I see that there are some BF981 avaible from time to time, but since they are discontinued, they may get hard to get. 73 de Thomas LA3PNA. 2012/7/22 wheverly1@verizon.net <wheverly1@verizon.net> > ** > > > The 40673 used to be a popular transistor in many projects. Unfortunately > as far as I can tell it is no longer readily available. Does anyone know of > a sustitute that is availale? > > Bill H. W3AOQ > > > -- Please avoid sending me Word or PowerPoint attachments. See <http://www.gnu.org/philosophy/no-word-attachments.html> PDF is an better alternative and there are always LaTeX! [Non-text portions of this message have been removed]
7636	2012-07-24 22:39:24	Russ Ramirez	Re: Transistor substitute
You can find them on eBay, but Dan's Small Parts has the 40673 and the 40822 substitute. http://www.danssmallpartsandkits.net/ Russ K0WFS [Non-text portions of this message have been removed]
7639	2012-07-25 23:01:37	wheverly1@verizon...	Re: Transistor substitute
Group, Thanks for all the help. I managed to procure some original 40673' and some 40822 as subs. As long as I don't destroy too many during my build I should be OK. Bill W3AOQ (since 1955) [Non-text portions of this message have been removed]