What with all the talk of the the end of cheap through-hole JFETs I figured I had better stock up while they are still reasonably cheap. Got myself a range of most-likely parts and decided to get a few hundred 2n5457s and J201s as they are so common for our use. Kind of a lifetime supply. I see that the 5457s are already shooting up in price. The J201's are dearer than they were but not OTT yet.
I broke with common wisdom and bought the J201's from Ebay (alert1) and China (alert2). Store was "Polida" who seem to have very good feedback. Anyway.... surprise surprise, they don't seem right.
So far I have tested for VGs off which seemed like the simplest quick test as there are not so many Jfets that have such a low parameter. There are right on the borderline of "spec" with about 30% going slightly over the maximum rating of -1.5v.
Its the cases of the transistors that have me really going "hmmmm" though.
The photo shows the Polida one on the left and a regular one from a known source on the right. Both are branded Fairchild.
First thing I noticed when I got the bag was that the Polida ones have a dry sanded look to them. Kind of like auto paint that has been wet and dry sanded. All the regular Fairchild Jfets I have have a nice shiny polished finish. There are other differences too. The case shape is slightly different. The "real" one has a letter code in the circle on the back. Different batches have different letters. The leads are different - the Polida ones flex more easily.
So they are the physical characteristics. I'll do some more testing soon.
So what do you think? Have you seen Fairchild Jfets that look like this?
Possibilities that come to mind:
The Polida ones could be old stock? Different die/factory?
Some unknown part just plain 'ol sanded and branded?
