Hi,
In my first job at Gould Advance Power Supply Div, Bishops Stortford, U.K. in the late 1970s. They had made a display of de-capped 2N3055 transistors.
I can't remember how many manufacturers were on this display, but there were maybe 7-8. The manufacturers were arranged on one axis and they had date codes on the other axis.
They used this to illustrate that there was not only a difference between manufacturers but how they changed over time. Hint, they did not get better.
The JEDEC spec only required a small subset of the published specifications to met, to call a transistor a 2N3055.
There were variations in:
1) die size
2) number and quantity of bonding wires. The old RCA parts had metal clips !!
3) The use of a heat spreader.
4) Case material, steel or copper.
To counteract this issue, transistors like 2N3772 were specified for use.
The other reason for being more specific, was FBSOA, varied considerably. This important for transistors being operated in the linear region.
I have been de-capping transistors ever since.
The picture posted by ddelectrical, is a very small die for a T0-3 package. I would like to put those on a curve tracer and see what kind of specs that they had. At the price they are I might just buy some...
I really encourage people who receive fake transistors to leave negative feedback. This way they are doing a service to those coming after them.
Regards,
Jay_Diddy_B
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