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- Trevor Wilson
April 6, 2005, 2:51 am

I was just working on an amp today and pulled a transistor out for testing
(with the very brilliant, Atlas tester). I had a thought: Transistors could
be made with a fourth lead. This lead would allow a sophisticated (but
inexpensive) testers (such as the Atlas) to interrogate devices and
ascertain the manufacturer/specs/etc.
--
Trevor Wilson
www.rageaudio.com.au
Trevor Wilson
www.rageaudio.com.au

Re: A good idea?
Phil Allison wrote:

Aussie parts would simply say ' she'll be right mate';
US parts would ask which country they should bomb next
English parts might ask does it matter if it leaks a little oil
NZ parts might say ' I naid sex ligs ta tist ut'
Irish parts might respond ' who me'?
David


Re: A good idea?

could
Well, if that was all that would be available via the extra leg, why not
just write it on the case? :-) But it's a good idea if they were to, say,
store the actual parameters of that particular device so you could compare
later (and I guess this is what you meant....). Hmmm, we could develop this
concept, but alas, I can't see it happening. Interesting though.
Cheers.
Ken

Re: A good idea?

Yeah right. They'd just counterfeit the 4th leg.
Its a stupid idea - add cost to every single part, so that if a device
fails, each component can be interrogated to find out what it was. A
colossal waste of money. Not to mention the fact that you only really
care about the *faulty* component, and if its faulty whats to stop the
fault from interfering with the ID. Murphy ensures that will always occur.
Best not to think about the reason for service manuals and BOMs....
Cheers
Terry

Re: A good idea?

**They could, but it may not be worth the effort. Don't forget what that 4th
leg is connected to.

**That is not the only reason for the extra leg.
A

**Nope.
Not to mention the fact that you only really

**Indeed. Read what I actually wrote though.

**And again.
--
Trevor Wilson
www.rageaudio.com.au
Trevor Wilson
www.rageaudio.com.au

Re: A good idea?

think a little harder about this. If its "not worth the effort" to
counterfeit, that must be because its too expensive. Hows that going to
affect the price of the original component? Clearly by increasing it.
And dont forget, the counterfeiters dont *have* to make the 4th leg
work. remember scam-RAM? no chips at all, just leadframes and plastic,
with mobo's jury-rigged to think report a cache.
anything the semiconductor vendor can do, the counterfeiter can *COPY*.

thats the one you talked about:
"I had a thought: Transistors could be made with a fourth lead. This
lead would allow a sophisticated (but inexpensive) testers (such as the
Atlas) to interrogate devices and ascertain the manufacturer/specs/etc"

what, first you require each (power) transistor to have another leg
(that will help reduce the manufacturing cost - not) with some circuitry
added to it that enables the device to be ID'd by a fancy tester (note:
all fancy testers would need to be replaced/upgraded, and 4-legged
transistor packages arent exactly commonplace), and that you later
assume wont be counterfeited (why not - too hard? not cheap then), then
blatantly assert that it *wont* be expensive? yeah, right.

how is a 4th lead going to help you identify a faulty power transistor
that has blown itself to pieces? any additional circuitry would be part
of the same die (to minimise cost, wire bonds aint free), so when it
fries the ID circuitry will probably fry too. There is more than enough
energy in the DC bus caps of even a moderate power amp to totally
destroy a power transistor - its only a little piece of funny glass,
after all.

Oh, I see, you dont want to have to read a service manual or BOM, you
want a fancy toy that does all the work for you.
ROTFLMAO!
Cheers
Terry

Re: A good idea?

**Indeed it will. By, potentially, a tiny amount. In the context of
expensive, power devices, that cost may represent an insignifant difference.

**Perhaps. Don't forget: Counterfeiters choose VERY cheap materials and
chips. They may not be able to effectively clone the 4th leg and the
associated electronics.

**Indeed. The inference was that a prospective purchaser could stroll into
DSE, Jaycar, wherever, Atlas (or equivalent) tester in hand and verify that
the components purchased are what they are purported to be.

**I never suggested that SOME extra cost may be involved. The potential for
substantial extra cost is unlikely, however. I certainly agree that low cost
devices would not benefit, simply because the cost WOULD be substantially
higher.

**Not necessarily.
There is more than enough

**Points:
* The main purpose of the idea is to allow identification of the
non-counterfeit devices.
* A BOM, service manual is not always available, for various reasons. This
is a serious problem in the service world.
--
Trevor Wilson
www.rageaudio.com.au
Trevor Wilson
www.rageaudio.com.au

Re: A good idea?
[snip]

in terms of Si, possibly. In terms of packaging, probably not.

unlikely, unless it utilises some seriously sub-micron geometry or
equally esoteric processing. Which will cost a *lot*. And until a large
chunk of the market has the necessary modified testers ($$$), copiers
dont have to make the 4th leg work, it just has to look sufficiently
similar to fool a purchaser at, say, DSE (not much of a task)

there is a serious problem with volumes here. Manufacturers build
seriously large numbers of components. Techs repair a small fraction of
those components - after all, the electronics is (or ought to be)
designed to have a long life. This is where the costs get out of
control, viz.:
Say its a $30 BJT, with $1 worth of 4th leg. If only one percent of
transistors need replacing, then for every $1 worth of 4th leg circuitry
that gets used, $99 *never* gets used as that equipment doesnt fail. No
manufacturer will put the more expensive devices into their equipment,
as the $1 adds no value *unless* the equipment blows up. Designers go to
great lengths to ensure stuff doesnt blow up (at least not until its out
of warranty) so it becomes useless expenditure. If no OEMs use the
devices, the foundry wont make them. simple economics.

So how do you identify a counterfeit device? performance. If it performs
exactly the same, who cares if its not the "real" part. If your
suggestion were ever to be adopted (not likely) then the counterfeiters
would, faced with a loss of income, counterfeit the 4th leg.
And say you do identify a counterfeit device at DSE, the counterfeiters
dont give a shit, they have *already* made their money. So DSE gets
upset, and eventually stops buying from that company. So they re-name
themselves, and DSE will buy from them once more (hey, they are cheap).
The real solution to counterfeit parts is to purchase from a reputable
vendor. And, of course, to cease purchasing on price alone (Deming,
Juran, Shewhart, Crosby et al)

very true.
Cheers
Terry

Re: A good idea?

I'm surprised no-one has suggested to put a PIC on each transistor, to
monitor a whole rage of parameters in real-time. And while you are at
it, why not add an ethernet port and IP-enable the whole lot? Then you
could check the specs of each device remotely over the Internet ... :)

Re: A good idea?
On Wed, 06 Apr 2005 07:26:20 GMT, swanny

Egads! I've been trying to develop such an arrangement, except for
monitoring zero ohm links!!! Do you know how much the extra patents
are going to cost me if I have to protect intellectual property on
monitoring technology for transistors, diodes, leds, pcb pads, spst
switches, dpdt switches, capacitors ...

Re: A good idea?

No , it would need wireless.
Quite a few of the top of the line fpgas come with ethernet in them.
Xilinx vertex4 FX with up to 4 10/100/1000 ethernet macs and ppc cores
http://www.xilinx.com/products/tables/virtex4.htm
Also altera stratix2 claims a 10GB ethernet XSBI using 16bit LVDS
Someone jokingly suggested adding wireless and one of the reps
said it was being looked at for future products.
A few of you guys may be interested in XFest2005
http://www.memec.com/?cmd=detail&articleid17%24
http://www.memec.com/?cmd=detail&articleid20%99#australia
For cheap fpga boards (other than for XFest)
http://www.xilinx.com/products/spartan3/s3boards.htm
http://www.xilinx.com/products/spartan3e/s3eboards.htm
are made by
www.digilentinc.com also for addon modules
Alex
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