Do these FETs look legit?

[theehman]

Haven't yet had a chance to try them in a circuit but I bought 10 each of these from a small storefront on the web and I want to make sure they're legit before I purchase more.

L-R
Fairchild 2N7000
unknown BS170
National 2N5457

[GibsonGM]

Yes, they look legit. Doesn't mean they ARE, or AREN'T, tho - any reason to be suspicious of them?

If they were 'abused', of course they could be defective, as anything could....maybe breadboard something very simple (basic gain stage) and try 'em out!!   Then you'll REALLY know  )

[theehman]

Just that I bought them from a small store.  I suppose by that logic they may be the real deal since they probably don't have the inventory turnover.
Are FETs being counterfeited?
Any idea who the BS170 was made by?

[Mark Hammer]

As I am given to understand, BS170s are static sensitive.  Does this distributor know that?  I recall well a place where I bought out their last MN3007s a number of years back, and they were just loose in the drawer without any protection whatsoever.  You wouldn't want to buy otherwise legit BS170s that ended up damaged by static and improper handling.

[psychedelicfish]

Are FETs being counterfeited?

If you want an answer to that question, buy some of Tayda's "J201s". Then, breadboard this circuit to measure I_DSS and V_GS(off). I think you'll find definitive evidence to suggest that yes, JFETs are being counterfeited.

As I am given to understand, BS170s are static sensitive.

They are MOSFETs, so a high voltage static pulse could cause a breakdown of the SiO₂ layer between the gate and the channel, making it useless (but you probably already knew that).

[duck_arse]

the bluish paint, bent centre pin and "phxx" makes me think the bs170 is made by philips or one of their euro compatriots. I have some bc series with both blue and silver paint.

speaking of tayda and static, I bought some 2n7000 from them, and they came on a very cardboard looking bandolier. not an antistatic in sight.

[midwayfair]

speaking of tayda and static, I bought some 2n7000 from them, and they came on a very cardboard looking bandolier. not an antistatic in sight.

I lost abag of BS170s from them to static a couple months ago. Couldn't even compare them with the known real-deals.

100% Smallbear for those, now, too.

[GibsonGM]

Yup, Smallbear is the real deal. 

If you want to know, breadboard this booster: http://www.muzique.com/tech/bipolar-m.htm
and sub in MOSFETs.    Then you'll know if the store was legit or not.

[midwayfair]

Oh, this relates to the "Do they Fake JFETs now" thread: It's not so much that the transistors aren't any good, it's just that they might be out of spec, B stock, remarked from another less desirable component, copies, or otherwise not exactly what they say on the case. So most of the time they work ... just maybe not always as consistently as they're supposed to, though occasionally they will just be flat out not what they say.

GibsonGM: Part of the problem there is that a BJT will work just fine in that set up. How confident are you you can tell the difference?

To me, the better way to check that it's even a mosfet would be with forward voltages, which are different depending on which way you conduct them.

[GibsonGM]

Yup, be

Oh, this relates to the "Do they Fake JFETs now" thread: It's not so much that the transistors aren't any good, it's just that they might be out of spec, B stock, remarked from another less desirable component, copies, or otherwise not exactly what they say on the case. So most of the time they work ... just maybe not always as consistently as they're supposed to, though occasionally they will just be flat out not what they say.

GibsonGM: Part of the problem there is that a BJT will work just fine in that set up. How confident are you you can tell the difference?

To me, the better way to check that it's even a mosfet would be with forward voltages, which are different depending on which way you conduct them.

Yup, best way would be to find Vp Idss and so on, but for a beginner?  Seems like you just have to try them in a known circuit. At least you'd know they're not static-zapped.  Might be after you handle them, tho, ha ha.....  *shrug* 

Do you think the mosfet boost would work WELL with a BJT, without different resistor values?  (actual question)

[midwayfair]

Do you think the mosfet boost would work WELL with a BJT, without different resistor values?  (actual question)

Actually, yeah, it works decently. It distorts a little earlier and isn't as loud. A darlington actually works pretty well (but has less treble).

[GibsonGM]

Do you think the mosfet boost would work WELL with a BJT, without different resistor values?  (actual question)

Actually, yeah, it works decently. It distorts a little earlier and isn't as loud. A darlington actually works pretty well (but has less treble).

That makes sense.    So, we send the OP off to ROG to measure the FETs with the Fetzer rig!