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12th Feb 2011, 9:04 pm | #1 |
Triode
Join Date: Feb 2007
Location: Wiles-Barre, PA USA
Posts: 34
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Which BF245 FET to use?
The reflex receiver circuit, link below, originally used a HEPF0015 FET which cross references to the BF245:
http://www.crystalradio.net/transist...ges/snare2.jpg Now, BF245 FETs come in A, B and C versions and so I am wondering which version would be the best suited for this circuit? Norman Bourassa |
12th Feb 2011, 9:40 pm | #2 |
Dekatron
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,548
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Re: Which BF245 FET to use?
It probably won't make a lot, if any, difference in that sort of circuit. Here is a data sheet that covers all three versions. You can compare it with the data sheet of the original type.
http://www.fairchildsemi.com/ds/BF/BF245C.pdf SB
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12th Feb 2011, 9:54 pm | #3 |
Dekatron
Join Date: Feb 2003
Location: Cottingham, East Yorkshire, UK.
Posts: 5,737
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Re: Which BF245 FET to use?
The differing charcteristics are listed in the datasheet here.
http://pdf1.alldatasheet.com/datashe...ENS/BF245.html Hope that helps a bit. I wouldn't have thought that in such a simple circuit there'd be any discernable difference whichever version BF245 you used, but that's just my view. Best of luck with the project. David |
12th Feb 2011, 9:59 pm | #4 |
Dekatron
Join Date: Sep 2006
Location: Kilmarnock, Ayrshire, UK.
Posts: 5,420
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Re: Which BF245 FET to use?
It really should make little difference as the lads have said.
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12th Feb 2011, 10:00 pm | #5 |
Retired Dormant Member
Join Date: Feb 2011
Location: Amsterdam, Holland
Posts: 36
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Re: Which BF245 FET to use?
Hello,
The drain current is diffrent when Vgs = 0.(see attachement). I think the difference will hardly be noticed in your circuit. Greetings, Bertus |