One for the electronics dabblers

Having used 3055 type bipolar transistors for years with all manner of prefixes and suffixes in either TO3 or TO220 packages, I opened up something to repair today to find a MTP3055E inside and behaving strangely.
Turns out it is an N channel Mosfet! GRRR!
http://www.sycelectronica.com.ar/semiconductores/MTP3055E.pdf
Of all the numbers they could have given it why choose 3055 that so widely known for being a bipolar power transistor.
Moral: Don't assume anything!
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On 15/01/2018 12:15, Bob Minchin wrote:

That's not smart, I would have assumed the same.
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On Monday, 15 January 2018 12:46:24 UTC, Fredxx wrote:

I guess it's difficult if you just refer to 4 digits to describe such a thing. I have mine labled as 2N3055 . 3055 is also the code for an alpha wire. I wouldn't allow my studetns to just type 3055, I'd expect them to be able to type the name in and order code and supplier, that's what teaching is about. ;-)
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On 15/01/18 12:15, Bob Minchin wrote:

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.... :-)

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The Natural Philosopher wrote:

But there was a TIP3055 which a bipolar power transistor
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On 15/01/2018 18:24, Bob Minchin wrote:

There is still a MJE3055.
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On Monday, 15 January 2018 12:12:35 UTC, Bob Minchin wrote:

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
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On 15/01/18 13:14, snipped-for-privacy@gmail.com wrote:

Oh dear.
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 45v IIRC
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On Monday, 15 January 2018 22:33:26 UTC, The Natural Philosopher wrote:

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.
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In article <97d70232-71a0-41bc-965e-

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
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Were they one of those devices where they were all made the same, measured afterwards and then labelled?
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snipped-for-privacy@davenoise.co.uk says...

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:
http://pdf.datasheetcatalog.com/datasheet/philips/BC107_108_ 109_4.pdf
I suspect this make 'em 'n' measure 'em procedure is much older than semiconductors.
20% carbon composition resistors, for example, when there were only 6 values in each decade and there was no guarantee of every one containing the same amount of carbon in the mixture they were made from.
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.
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On Tuesday, 16 January 2018 11:55:31 UTC, Terry Casey wrote:

All transistors were make & measure for decades. Greater uniformity came later.
NT
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On Tuesday, 16 January 2018 11:55:31 UTC, Terry Casey wrote:

All transistors were make & measure for decades. Greater uniformity came later.
NT
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On 16/01/2018 11:18, Dave Plowman (News) wrote:

They still are as are cpus and RAM, etc.
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On Tuesday, 16 January 2018 16:45:05 UTC, dennis@home wrote:

and people.
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On Tuesday, 16 January 2018 11:10:46 UTC, Terry Casey wrote:

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.
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On Monday, 15 January 2018 22:33:26 UTC, The Natural Philosopher wrote:

Must be a while since you read any transistor data sheets



they can, but that isn't the issue. Here's what wiki says:
"With changes to semiconductor manufacturing technology, the original proce ss became economically uncompetitive in the mid-1970s, and a similar device was created using epitaxial base technology.[1] The maximum voltage and cu rrent ratings of this device are the same as the original, but it is not as immune from secondary breakdown; the power handling (safe operating area) is limited at high voltage to a lower current than the original."
NT
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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
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