One for the electronics dabblers

That's not smart, I would have assumed the same.

Possibly becasue it has similar power ratings and so on.

But it was a *2N*3055 that was the bipolar.

Not the AC3055, or the OC3055 or the BFY3055.... :-)

There's also the fact that not even all 2N3055s are the same type of device. Older and later ones are different process and differ significantly.

NT

I guess it's difficult if you just refer to 4 digits to describe such a thing. I have mine labled as 2N3055 .

Yes the old 2N3055 could easily be persuaded to run at medium wave and put out quite a bit of rf. Not that I'd ever have done such a thing of course.

Brian

But there was a TIP3055 which a bipolar power transistor

There is still a MJE3055.

a transistor spec is a minimum spec.

Not a maximum, not a typical.

so its perfecly possible that significantly better transistors can share the same part number.

e.g. back in te day most BC107 would handlee 70V. but the spec only said

No most specs of transostors of typical lower and upper levels for the same numbered device. Some may have prefixes denoting changes to specs.

I've had BC107A BC107B BC107C and now we have differnt sizes of surface mount devices also with slightly differing specs.

In the case of the BC107 range, the A, B and C versions were graded according to their DC current gain into three bands.

A BC107 without a suffix could have gain figure anywhere in the range of 110 to 450.

The BC108 had an even greater gain spread - from 110 - 800

Were they one of those devices where they were all made the same, measured afterwards and then labelled?

and there't the BC109a,b,c

Other confisions are when the BC182L and BC182K are the sma e spec but differnt pinout.

We tend to use the 2N2222A more now and I'm trying to replace them with the cheaper versions PN2222 as for what the students use them for they should be OK.

Almost certainly - in fact, when they were released in the UK by Mullard they had no suffxes and I don't ever recall seeing a Mullard branded one that did although the parent company, Philips, shows them clearly on its datasheet:

I suspect this make 'em 'n' measure 'em procedure is much older than semiconductors.

The first varicap diodes designed for use in UHF and VHF tuners had such wide variations that Mullard sold them in individually matched sets because of the need for all the tuned circuits in a tuner unit to track accurately.

I assume it was easier/cheaper for the tuner manufacturers to buy them in bulk and test/sort them for themselves, though.

Must be a while since you read any transistor data sheets

NT

All transistors were make & measure for decades. Greater uniformity came later.

NT

All transistors were make & measure for decades. Greater uniformity came later.

NT

They still are as are cpus and RAM, etc.

and people.