Rock solid mosfet

Started by Danich_ivanov, March 31, 2018, 09:36:20 AM

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Danich_ivanov

So i bought a bag of bs170, they were in a plastic bag, which is how all the components ship from my supplier, and there is nothing i can do about it, which i assume resulted in half of them not working at all. On the other hand i have rf640, and it is rock solid, i can toss it around just like a jfet or bjt, and it still works, the problem i have with it is that it's enclosure is not pedal friendly, so here's a question: are there mosfets which are just as rock solid, but in a standard to-92 enclosure?

Thanks.

ElectricDruid

Why do you assume that half of them are not working? Have you tested them all and found this? ("Assume" makes it sound like not.) How did you test them?

It would be pretty short-sighted of a seller to send components in a manner which produced 50% losses in transit. That alone makes me think it is extremely unlikely to be the case,.

Tom

Danich_ivanov

You slightly misunderstood me, or perhaps i said things the wrong way, i meant that i assume that half of them are not working because of the way they were shipped, which may or may not be the case. And yes i tested them, otherwise i wouldn't say that half of them are not working (and half is a round number), i tried various pinouts, pots for biasing, all the usual stuff, google, where one works, the other one doesn't, could be a bad batch, but either way i'm not playing this lottery again, which made me ask the question i asked.

GibsonGM

Any chance you can find a different and more responsible supplier?  I would demand they give me my money back!
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Danich_ivanov

Well, you know, it's a mosfet, a quite sensitive thing, and i don't bother getting three dollars back, usually things are good over there.  :)

ElectricDruid

Ok, so you bought a $3 bag of mosfets and you reckon after testing some or most of them that about 50% are good? Is that right?

So how many were in the bag?

With the prices I'm seeing for BS170 from reputable suppliers, $3 gets you ten mosfets, give or take. If you buy a batch of thousands, obviously you can cut that to 20% or less of that price, but I'm guessing that's not your situation.

If you paid $3 and got 20 mosfets, then I'm not surprised that 50% were bad. Welcome to the wonderful world of "grey market" electronics...sigh. Unfortunately this is what we put up with. If life was simple, everything would be so. much. easier.

T.

italianguy63

I don't generally use MOSFETs that much.. but this thread made me look at my parts bin(s).

Yeah, I have about 25 BS170's... and they are on cardboard "tape"-- and it is unusual because it is foil covered tape (anti static).. never noticed before...

MC
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Danich_ivanov

Yes, they should be protected, otherwise bad things can happen. I wasn't a mosfet user myself before, it used to be jfets all over the place, but once i figured that there might not be enough jfets in a retail for my future needs i started forward thinking and decided to get into mosfets, and these irf640 are actually pretty good, and seem to be free from usual static issues.

GGBB

The 2N7000K is an "ESD protected" variant of the 2N7000 that is still offered in the TO-92 package. Available from Taiwan Semiconductor and possibly others. Vishay made one but I think it's now obsolete and replaced by 2N7002K which doesn't come in through-hole.
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Danich_ivanov

Thanks for a tip! although i checked with my supplier, and unfortunately it doesn't have a "k" variant. I'm kinda started to give up on this, i may just go with RF series since i have experience with them, and i know that they work well for sure, and in the end figuring out how to fit things together is much easier than dealing with exotic, probably irreplaceable part.

anotherjim

Way back, I remember singles of mosfets came with the leads twisted together. Can't really esd shock them like that.

ElectricDruid

Sorry, I was being a bit combative in this thread. Not my intention, but it definitely comes over like that re-reading it a few days later. My apologies, Danich. May your mosfets ever be free of static damage! :)

T.

Danich_ivanov

no worries, it happens to all of us once in a while  :)