I need a T039 NPN transistor with an 80 volt BVceo rating such as a BC142.

My nearest stockist holds the BC141 which has a BVceo rating of 60volt.

If I buy a BC141 and test the breakdown voltage, what are the chances that
it will exceed 80volt?



I would also like to know how manufacturers make these almost identical
transistors with different voltage ratings.



Do they just make a batch of BC140s and those which exceed 80v get stamped
'BC142'?



Or do they make separate production runs for each type?



Also, do the higher voltage versions loose out on some other parameter such
as gain?



Many thanks,

Rudge