BC337 testing

hi everyone
firstly i'm an electronics noob
i just purchased a box of fake fairchild bc337-25 from ebay(not for a project just to tinker with), and was wondering how i could test them, so as to compare to the specs of genuine 337's. the fairchild datasheet only gives characteristics information, and no suggested circuits to test.
so far i can continuously draw about 400mA through one of the fakes, but at about 500mA the smoke comes out.

so basically my question is what easy tests can i perform to best compare the fake against the real specs ?

warm regards
gaz
 
The humble BC337 can only handle 45V between collector and emmiter (50V across CB, 5V for EB), 800mA from C to E but also just 625mW to dissipate.
With your 500mA, the Vce should be kept lower then (625mW/500mA=) 1.25V.
Check for the beta if it is in the expected range.

How do you know they're fake? And why the sweat?
 

Attachments

  • BC337.pdf
    185 KB · Views: 54
thank you for the reply citizen
i dont know for sure that they're fake, but i purchased them from ebay and they were so cheap that i assumed they must be !
the beta is in the expected range. and when i tried to test the 800mA i was running about 15V through some high power led's
no sweat, i just wanted to see how they compared to genuine parts, and was hoping for a couple of circuits that i could use to test them.

warm regards
gazza
 
hi asuslover
here are the pics

IMG_20230919_002600.jpg

IMG_20230919_002628.jpg
 

Attachments

  • IMG_20230919_002550.jpg
    IMG_20230919_002550.jpg
    471 KB · Views: 24
  • IMG_20230919_002631.jpg
    IMG_20230919_002631.jpg
    302.2 KB · Views: 26
hi everyone
firstly i'm an electronics noob
i just purchased a box of fake fairchild bc337-25 from ebay(not for a project just to tinker with), and was wondering how i could test them, so as to compare to the specs of genuine 337's. the fairchild datasheet only gives characteristics information, and no suggested circuits to test.
so far i can continuously draw about 400mA through one of the fakes, but at about 500mA the smoke comes out.

so basically my question is what easy tests can i perform to best compare the fake against the real specs ?

warm regards
gaz
I am not sure they are fake.

TO-92 usually have a max power rating of 0.6W.
That would be 1.2Volt Vce and 500mA.

As said, usually they are used at 50-100mA.
Most any TO-92 would break down with 500mA and more than 1 Volt VCE.
 
  • Like
Reactions: 1 user
Beta is going to fall at full current rating. But it should stay in the 40 to 50 range. If you force 20 mA into the base, you should be able to pull the collector down to under a volt. If you can’t, then I’d suspect fakes (or some lower current device marked as the higher current one).

The whole reason to choose these devices in the first place is that they are very competitive with those high beta low vce(sat) Zetex parts - at least the ones rated at one amp. That’s what they should be able to do.