Which FET?

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#1
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Witch FET to buy?

I have used BF245, A and B, but DigiKey do not have those. I need a cheap, general purpose FET, A and B. TO92 are OK. DigiKey are, for us, an ok source.

HM

HM

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Operating voltage?
Continuous current?

JC

Captcha'd for this! ???

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Here are a datasheet of BF245:

http://media.digikey.com/pdf/Dat...

I am not "familiar" with FETs. I guess 15V and 15 mA will do for me. I will try it as a preamp. for a heart beat sensor.

HM

HM

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I wasn't sure if you were using it for small signal switching, or looking for a higher current rated device.

For many applications I've used the 2N7000 (TO-92 through hole package), 2N7002 (SOT23-3L Surface mount package).

Vdss = 60 V
Id = 350 mA
Rdson < 5 ohms, (Typically 2 ohms)

It is readily available from lots of suppliers.

JC

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I second the 2n7000/2n7002 recommendation. I bought some of the 7002's from tayda where they're 4c ea.

I have no special talents.  I am only passionately curious. - Albert Einstein

 

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2N7000 is not a re[lacement, it is a totaly different kind of device.
Try sourcing 2N5484, 2N5485 or 2N5486 as a last choice based on gate pinch off voltage specification.

Just checked Digikey. the part no longer stocked . Same at Element14.

Digikey do have

http://www.digikey.com/product-d...

http://www.digikey.com/product-d...

Yes it is grim.

Element14 do have SMD equivalents if that is any help.

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google "BF245 replacement" give this :
http://www.soselectronic.com/?str=1184

So BF545

But if you don't need the speed go for one of the others

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A bf245 is a jfet. Fine if you want to switch audio. If you want to switch a relay or led, then you want a mosfet like the 2N7000/2 suggested.

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My local supplier (www.reichelt.de) has BF245B and BF245C in stock. I could order some and send them to you.
If you need only 2, I have enough to send you 2,
give me a PM.

BFR31 or BF 5484 or 2SK192 might do the job also.