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'[EE] Jellybean transistors'
2011\01\21@132533 by Philip Pemberton

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Hi guys,

At the risk of starting another holy war or Mass Thread of Off-Topicness as I seem apt to do...

I was recently chatting with a friend, and we got onto the subject of 'jellybean' parts, via a discussion on the construction of read-write amplifiers for disc drives (seriously!)

Anyway. He proposed a current-mirror with two switches, good to 1MHz or so, based on a bunch of 2N3904s. I commented "That's great, but I don't have any 3904s, just a box full of BC547s and BC847s". To which he replied "Are you serious? 3904s are jellybean NPNs and you don't even have one of them?"... He proposed that I get a box of 2N3904s and 2N3906s as a matter of some urgency...

So I'm skimming the datasheets for the 3904 and the 547, and they don't seem all that different....
  * Vceo is slightly better on the 547 (45V vs 40V)
  * Vcbo is slightly worse  on the 547 (50V vs 60V)
  * Vebo is still the same old 6V on both
  * Max collector current is worse on the 547 (100mA vs 200mA)
  * Hfe is roughly the same, assuming we're talking about the B-spec BC547 (aka BC547B)
  * Slightly less input and output capacitance on the BC547
  * Better typical noise figure on the BC547 (2dB vs 5dB)
  * They both have the same Ft (gain-bandwidth product) of 300MHz, suggesting they'll both go to 100MHz if the current gain is kept below 3x
  * Fairchild don't tell you as much about the 547 (no detailed on-off characteristics, just a few vague graphs). No details on rise/fall time, breakdown voltages or cutoff current.
  * The pinouts are mirrored -- the 547 is C/B/E, the 3904 is E/B/C. So you could put one in a socket intended for the other by rotating the transistor 180 degrees...

But other than that they seem to be basically the same thing by a different name -- "a rose by any other name". Which brings me to my questions:

  - Is there any point to getting some 3904s and 3906es? So far the best reason I've got is "so I've got a few to play with" (which isn't that good a reason). All my R. A. Penfold books call for the BC547 (or one of its brethren), Horowitz & Hill demands the 3904.
  - Are there any other jellybean parts I should look into keeping around? I already have some BD139 and BD141 medium-power parts and a few MJE3055 and MJE2955 TO220 high-power parts, and some 2N7000 MOSFETs, but that's mostly it (aside from a few ST and IRF high-power FETs, and some BF998 dual-gate MOSFETs and 2N3819 JFETs)...

Thanks,
-- Phil.
spam_OUTpiclistTakeThisOuTspamphilpem.me.uk
http://www.philpem.me.uk

2011\01\21@133734 by Sean Breheny

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Hi Phil,

I think that this is a case of the US versus Europe. The 2N3904 is a
jellybean BJT in the US. The BC series parts you have are, I believe,
equally "jellybean" in Europe. It's an issue of which exact transistor
design was popular with different manufacturers and where they
typically sold them. I think that most designs should not be sensitive
enough to care about the differences you mention. It might be good to
have some of each type around in case you want to duplicate some
specific design which was done in the US and specs out the 2N series
parts.

Sean


On Fri, Jan 21, 2011 at 1:25 PM, Philip Pemberton <.....piclistKILLspamspam@spam@philpem.me.uk> wrote:
{Quote hidden}

>

2011\01\21@134402 by jim

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Phil,

In my opinion, if you already have some NPN transistors that are
roughly equivalent to tne 3904,
then I see no reason to buy any.  The 3904 and 3906 transistors are
basically the same spec with
complimentary polarities.

One saving grace to both the 3904 and the 3906 is that they are cheap. Like 10-20 for a dollar.
Again, that isn't really a justification to buy any, especially if you
already have a rough equivalent.

Bottom line from my perspective..Use you 547's / 847's, and pass on
buying the 3904 / 3906 for the time
being.

Final call is yours though.
Regards,

Jim

> ---{Original Message removed}

2011\01\21@134610 by Olin Lathrop

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Philip Pemberton wrote:
> "Are you serious? 3904s are jellybean NPNs and you don't
> even have one of them?"... He proposed that I get a box of 2N3904s and
> 2N3906s as a matter of some urgency...

Yes, some people are fixated on the 2N3904/3906, just like they were on
2N2222A before that.  The 3904/3906 are cheap and available, but otherwise
their specs are not impressive.  I use the 2N4401/4403 for jellybean
transistors.  They are also readily available and cheap, but a bit more
robust and better for most cases.  It's a good idea to have some jellybean
parts in stock, but if they can't be used in a large number of applications
then it defeats the purpose a bit.

>    - Are there any other jellybean parts I should look into keeping
> around?

Get a bunch of at least every 5% value of resistor and a good assortments of
caps, a NPN/PNP pair of jelly bean transistors, but then I'd wait until you
need something.  When you do and it looks at all generally useful, get a
bunch and keep the extras around.

Unless a part is expensive, we don't buy just what we need.  We pretty much
always get at least 10, or 100, or 200, 500, etc, whatever is the next price
break after what you really need.  Sometimes we get whole reels just to have
around if they are cheap enough.  I got a real of 0603 green LEDs for about
$0.02 each a few years ago and it's been handy to have them around.

Having basic stuff in stock is useful, but technology moves on too.  For
example, we have a handful of PIC 16F876 that probably won't get used
anymore.

I just looked at our wall of small parts cabinets.  There are a total of
1354 small drawers, which look to be 80% used.  With parts also in other
places, it looks like we have 1100 different part types around.  Most of
this has come from buying extras.  Even so, there are always new parts to
get every project.  It's a never-ending process.

2011\01\21@134943 by Picbits Sales

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I think a lot of it is down to how you were "brought up" with Electronics.

I  grew up with RA Penfold and I'm pretty sure my first electronics book was by an author called "Sparkes" but I'll have to dig it out to verify this. BC5xx transistors were widely used in these books and magazine articles.

I used to buy surplus bags of BC series transistors from a little model shop in Mill Hill when we visited my Grandparents who lived there. That was just about the only opportunity I had of buying cheap electronic components as a kid as Tandy were too expensive.

In fact ..... its only in the past few years that I've actually started using PNP transistors as during my early years, my only exposure was to NPN devices lol. I'm nearly 40 now so this shows how far back I'm going .....

Dom

{Original Message removed}

2011\01\21@140557 by Philip Pemberton

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On 21/01/11 18:47, Olin Lathrop wrote:
> I use the 2N4401/4403 for jellybean
> transistors.  They are also readily available and cheap, but a bit more
> robust and better for most cases.

The 4401 looks like a nice part. Shame the SOT23 version (MMBT4401) is currently out of stock at my main supplier with no quoted leadtime :(

> Get a bunch of at least every 5% value of resistor and a good assortments of
> caps,

I've got a Dannell Electronics through-hole quarter-watt E12 1% metal-film kit, and a couple of Fastcomponents ceramic-disc kits. Everything else is pretty much "buy when needed". I really should get an E6 0805 capacitor kit; NP0 for the low-value stuff, X7R for everything else..

> I'd wait until you
> need something.  When you do and it looks at all generally useful, get a
> bunch and keep the extras around.

Sounds like my general buying procedure :)

If price_for_ten < price_for_however_many_i_need then buy ten.

Means I've got rails of stepper motor driver chips and other such things left over from when I repaired a scanner, a bunch of LM358 opamps (25 each SO8 and DIP8 at last count, mfg by ONSemiconductor if memory serves).

> Having basic stuff in stock is useful, but technology moves on too.  For
> example, we have a handful of PIC 16F876 that probably won't get used
> anymore.

Aye, I've got loads of PICs I don't plan on using anymore. I found some of my original 16C84s -- the first PICs I bought -- in an old toolbox the other day.

> I just looked at our wall of small parts cabinets.  There are a total of
> 1354 small drawers, which look to be 80% used.  With parts also in other
> places, it looks like we have 1100 different part types around.

About 900 different part types here, counting different values. When I need something, I usually just pick something that 'looks about right'. ICs are the main things I have to buy in. Heck, I just bought a rail of ten Texas Instruments CDC925 fractional-N PLL clock generators because they're great for generating weird clock frequencies from a jellybean 10 or 20MHz crystal... When they're only a few quid each, it's really not worth crying over...

Oh, and it cost less to buy ten than it would have cost to buy the five I needed :)

-- Phil.
.....piclistKILLspamspam.....philpem.me.uk
http://www.philpem.me.uk

2011\01\21@151255 by Dwayne Reid

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At 11:25 AM 1/21/2011, Philip Pemberton wrote:
>I don't
>have any 3904s, just a box full of BC547s and BC847s". To which he
>replied "Are you serious? 3904s are jellybean NPNs and you don't even
>have one of them?"... He proposed that I get a box of 2N3904s and
>2N3906s as a matter of some urgency...

The way I see it, you already have jellybean transistors - just with different part numbers.

I used to use 2n3904 & 3906 as my jellybean transistors until a buddy put me on to the 2n4401 & 4403 parts.  I still keep the '3904 & '3906 transistors around but I design in the '4401 & '4403 parts now - I've found them to significantly more robust than the '390x parts I used to use.

But jellybean is jelly bean - low cost, decent specs.  The parts you are currently using qualify.

dwayne

-- Dwayne Reid   <EraseMEdwaynerspam_OUTspamTakeThisOuTplanet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(780) 489-3199 voice          (780) 487-6397 fax
http://www.trinity-electronics.com
Custom Electronics Design and Manufacturing

2011\01\21@151537 by Olin Lathrop

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Philip Pemberton wrote:
> The 4401 looks like a nice part. Shame the SOT23 version (MMBT4401) is
> currently out of stock at my main supplier with no quoted leadtime :(

These are very common parts, so plenty of folks have them.  I just checked,
and Mouser, DigiKey, Newark, and Jameco all have available stock.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000

2011\01\21@152311 by Wouter van Ooijen

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> He proposed that I get a box of 2N3904s and
> 2N3906s as a matter of some urgency...

When I designed the first Wisp progger I needed a non-special-specs NPN transistor. I used an USA source (I think mouser) to find the cheapest through-hole part and landed on the 2N3904. Later I redesigned the PCB and selected the cheapest I could get from a European source and landed on a BC550 (which is essentially a slightly better BC547). It's just geographical location. If was Asian I would probaly have use an SC-something.

Long ago the (then quite good) Dutch electronics magazine Elektuur used two 'general pupose' transistor types in most of their designs: TUN and TUP, for Transistor Universal NPN / PNP, whith a list of minimal specs for these types (they also used DUG and DUS diodes). They had a list of types that conformed to the these 'virtual' types. IIRC BC547 and 2N3904 were both TUN-conforming.

--
Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu

2011\01\21@155511 by Philip Pemberton

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On 21/01/11 20:23, Wouter van Ooijen wrote:
> Long ago the (then quite good) Dutch electronics magazine Elektuur used
> two 'general pupose' transistor types in most of their designs: TUN and
> TUP, for Transistor Universal NPN / PNP, whith a list of minimal specs
> for these types (they also used DUG and DUS diodes). They had a list of
> types that conformed to the these 'virtual' types. IIRC BC547 and 2N3904
> were both TUN-conforming.

I've got the whole run of Elektor in dead-tree (from 1974 to 1989) and PDF (the 1990-1999 uber-archive DVD and all the Subscription-Plus DVDs since then), and I've seen the article you mentioned. As I recall, they had several categories:
  TUN/TUP -- universal silicon NPN/PNP
  DUG/DUS -- Diode, Universal, Germanium and Diode, Universal, Silicon.

A nice idea, shame none of the current crop of hobbyist magazines do it any more...

-- Phil.
piclistspamspam_OUTphilpem.me.uk
http://www.philpem.me.uk

2011\01\21@171241 by IVP

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Phil,

now someone with an overactive spritual disposition would
probably make a big illogical deal of this

After reading your thread I went up to the mailbox. There at
the end of our driveway is ....

http://dl.dropbox.com/u/18683201/2N2904.jpg

woohoohoohoohoo

Pull them covers up tight

Jo

2011\01\21@172349 by Marcel Duchamp

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On 1/21/2011 2:10 PM, IVP wrote:
> Phil,
>
> now someone with an overactive spritual disposition would
> probably make a big illogical deal of this
>
> After reading your thread I went up to the mailbox. There at
> the end of our driveway is ....
>
> http://dl.dropbox.com/u/18683201/2N2904.jpg
>
> woohoohoohoohoo
>
> Pull them covers up tight
>
> Joe

That vehicle owner's spouse should get plates reading "ZN3906" - then they would have a push-pull relationship

2011\01\21@173541 by IVP

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> That vehicle owner's spouse should get plates reading "ZN3906" -
> then they would have a push-pull relationship

Haha. Once upon a time the fates were in the tea leaves

Indulge me with just one more [OT] moment. A few doors down
is a sporty black stationwagon with the plate OVARYD

Which, because I've only ever seen a woman in it, I have always
read as 'ovaried'. A strange boast I thought, for a not uncommon
physical trait

A visitor suggested that maybe, just maybe, it's supposed to be
read as 'over-ride'

Ah. Oh. Yeah, guess so

Joe

PS I agree with Olin about the 2N440x, and I've stripped a lot
of boards with both 2N390x and BC types. 2SC945 was/is
popular to

2011\01\21@175658 by peter green

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Olin Lathrop wrote:
> Philip Pemberton wrote:
>  
>> The 4401 looks like a nice part. Shame the SOT23 version (MMBT4401) is
>> currently out of stock at my main supplier with no quoted leadtime :(
>>    
>
> These are very common parts, so plenty of folks have them.  I just checked,
> and Mouser, DigiKey, Newark, and Jameco all have available stock.
>   Which is fine for americans like you.

On the other hand if you are in the UK thinks look much less rosy

Neither farnell or RS have stock or any indication of whether they will have stock
Digikey are a PITA to deal with from the UK (especially if one is dealing from a large and beuracratic institution that interacts in bad ways with the UPS behaviour I mention later) with their insistence on asking a shitload of export questions for even the most mundane of orders and their insistence on using UPS for foreign currency denomiated orders and UPS's insistence on collecting VAT before they will deliver the package. I consider using them to be a last resort.
Never tried dealing directly with newark from the UK but if the delivery charges are anything like those farnell charge for the subset newark items they list as "US Stock" then OUCH.
Jameco won't even tell you what the delivery charge is on their website.

So really that just leaves mouser and I'd rather not choose a jellybean part that is only availiable (and by available I mean in-stock at the time I choose it, not might reappear at some future date) from one supplier on my list of acceptable ones. Particulally when that supplier is an ocean away

2011\01\21@182046 by Philip Pemberton

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On 21/01/11 22:56, peter green wrote:
> UPS's insistence on collecting VAT before they will deliver
> the package.

I call bullshit.

1) You can pay UPS via credit card over the phone as soon as the customs/VAT invoice hits UPS HQ. Basically, once it leaves Stansted, that invoice will have been raised.

2) They WILL take payment on the doorstep. Last time I asked (a few months ago), they take credit/debit cards, cheques and cash. If you pay by cash, the drivers don't keep change -- so it's EXACT CHANGE ONLY.

3) If you pay over the phone, keep the Payment Reference Number they give you. The driver will need it to confirm that you've paid.

> Never tried dealing directly with newark from the UK but if the delivery
> charges are anything like those farnell charge for the subset newark
> items they list as "US Stock" then OUCH.

Last time I checked, the fees were pretty much the same.

> Jameco won't even tell you what the delivery charge is on their website.

Same as BG Micro, Prime and any number of other surplus suppliers I could name. "Call us, we'll add up the weight and send you a shipping quote."

> So really that just leaves mouser and I'd rather not choose a jellybean
> part that is only availiable (and by available I mean in-stock at the
> time I choose it, not might reappear at some future date) from one
> supplier on my list of acceptable ones.

Point taken. The BC547 is -- from what I've been told -- a bit of a pig to find in the USA (though DKUS and Mouser have them), but you ask any UK supplier (even the likes of Maplin...) and they'll have at least one or two in stock.

To turn that on its head: if you're in the USA, even Radio Shack stocks the 2N3904 (last time I checked, anyway). But $DEITY help you if you want a BC547 on short notice.

Geographical position makes a huge distance.

-- Phil.
@spam@piclistKILLspamspamphilpem.me.uk
http://www.philpem.me.uk

2011\01\21@191220 by Sergey Dryga

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Philip Pemberton <piclist <at> philpem.me.uk> writes:


> To turn that on its head: if you're in the USA, even Radio Shack stocks
> the 2N3904 (last time I checked, anyway). But $DEITY help you if you
> want a BC547 on short notice.
>
> Geographical position makes a huge distance.
>
What are the reasons for this? I do some shipping from US to Europe, does not seem to be problem. Also, just checked BC547 on mouser - $0.04 in 100 ea quantity. Shipping to UK is $30 (1 - 3 day delivery), shipping in US (New Mexico)FedEx
overnight - $30.
Maybe I am missing something, but I do not see much difference.  Maybe the
different experiences people have are due to the size/bureaucracy in the
organization they work in, rather than distance from
Mouser/Newark/DigiKey/Farnell/whatever?
Sergey Dryga
http://beaglerobotics.com


2011\01\21@192031 by peter green

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Philip Pemberton wrote:
> On 21/01/11 22:56, peter green wrote:
>  
>> UPS's insistence on collecting VAT before they will deliver
>> the package.
>>    
>
> I call bullshit.
>   By before delivering the package I meant before they will hand you (or the people in goods inwards) the package they want the money somehow and worse in our experiance they often screw up with matching up telephone credit card payments to the package.

Probablly not such a problem if you are ordering for yourself and prepared to sit in yourself to pay in person but the interaction of UPS's duty collection attempts with university beurcracy makes it a nightmare for us to buy from DK. I've tried to arrange for us to deal with them in USD (for some crazy reason digikey will let you choose your courior if you deal in USD but insist on UPS if you deal in GBP) but no success on that front either.

Combine that with the fun we have had with emails getting lost between us and digikey (dunno if that is our fault or their fault) and the fact that they never seem to retry sending them which has caused weeks of delay and one time when I was promised in online chat that a package would be shipped the following day and when I contacted them and asked again they said it hadn't been shipped and it was "their fault" but still didn't give a reason and the total time and pain becomes just not worth it unless I am really desperate for a specific part.

Fedex on the other hand deliver first and worry about vat/duty/fees later. Mouser are even better, they use a service called "International priority directdistribution" which afaict means mousers european subsidary are legally the importer and you just pay everying to mousers european subsidary (which is mostly a virtual office afaict but that doesn't matter for this)

2011\01\21@193516 by Oli Glaser

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On 22/01/2011 00:20, peter green wrote:
>   Mouser are even better, they use a service called "International
> priority directdistribution" which afaict means mousers european
> subsidary are legally the importer and you just pay everying to mousers
> european subsidary (which is mostly a virtual office afaict but that
> doesn't matter for this).

Agreed on the Mouser front, purchasing from them has always been a completely painless experience.

2011\01\21@193755 by Mark Rages

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On Fri, Jan 21, 2011 at 6:12 PM, Sergey Dryga <KILLspamsergeyKILLspamspamdryga.us> wrote:
> Philip Pemberton <piclist <at> philpem.me.uk> writes:
>
>
>> To turn that on its head: if you're in the USA, even Radio Shack stocks
>> the 2N3904 (last time I checked, anyway). But $DEITY help you if you
>> want a BC547 on short notice.
>>
>> Geographical position makes a huge distance.
>>
> What are the reasons for this?
> I do some shipping from US to Europe, does not seem to be problem.
> Also, just checked BC547 on mouser - $0.04 in 100 ea quantity.
> Shipping to UK is $30 (1 - 3 day delivery), shipping in US (New Mexico)FedEx
> overnight - $30.
>

Not sure I understand the direction this thread is going.

The whole point of jellybean transistors are that they have average
specs and are used in non-critical situations.

So if the BC547 has similar specs to the 2N3904, it seems madness to
expend great energy and shipping expense to source one of those when
the other is widely available locally.

Regrads,
Mark
markrages@gmail
-- Mark Rages, Engineer
Midwest Telecine LLC
RemoveMEmarkragesTakeThisOuTspammidwesttelecine.co

2011\01\21@194607 by RussellMc

face picon face
> Anyway. He proposed a current-mirror with two switches, good to 1MHz or
> so,

And a lot faster han that with a little care.
Have a look at how ECL works and note that it probably looks close to
what your friend is talking about.
Note how fast it is.
Note the modest but useful improvment sin the modern versions.
Note that it is still king, even though most people don't know it
exists any more.
Go and do thou likewise.


ellybeans.
I find that the best are often almost the cheapest.
I tend to use top current gain binned BC337/BC327 for through hole.
SOT23 equivalents for SMD (BC807/817/?)

500 ma.
Beta 250-600 range
45V

BC807-40 = beta 250-600 9400 ~~=sqrt(250 x 600)

Occasionally a few cents each in 100's at the right time and place.
About 1 cent in Asia, but that's not relevant.

Look for something available via your local channels that is as good
as possible for as little as possible and stock up when you find them
cheap.

Lessee

BC807-40 Digikey
www.onsemi.com/pub_link/Collateral/BC807-16LT1-D.PDF
SOT23
45V 500 mA,

39 cents / 1
26 cents / 10
11c / 100
3.7c / 1000

TO92 equivalent is BC327
Similar pricing to above
Mouser
6 cents / 1 !!!!!!!!!!!
4.4 cents / 100 !!! very good

Avnet 2.5 cents / 30000
About 2.5 x Asian prices.

Future 2.5 cents / 2k

__________________________________

On Jellybean FETS.
Do not use the execrable 2n7002 and friends.
ONLY good point is voltage rating of 60V
Otherwise it has pathetic Rdson, gate voltage too high for logic
driving (not even 5V let alone 3V) etc.

See my prior rants on nice small FETS.
Search archives on CES2310 or CETSEMI will probably turn up same.



   Russell








Buy 1000 and split amongst 10 friends gives 4 cents each










based on a bunch of 2N3904s. I commented "That's great, but I don't
{Quote hidden}

>

2011\01\21@195412 by RussellMc

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> So if the BC547 has similar specs to the 2N3904, it seems madness to
> expend great energy and shipping expense to source one of those when
> the other is widely available locally.

My aim with "jellybean" transistors is that they have GREAT specs for
most purposes AND cost less than most alternatives (better cheaper
faster choose any 3). So you can "just use them".

eg BC327-40/BC337-40/ BC807-40/BC817-40
hile these are notionally "European" parts, many many US distrobutors
have them at good prices.
(eg see http://www.findchips.com)

Superb Beta (current gain)
Good saturation
500 mA Ic
Vc 45V good enough for most uses.

95% to 99% of the time you can use one of these and it will have as
good a spec for the task as anything you would have used by design.
For a PIC gate driving a load or a audio ish digital filter or long
tailed instrumentation pair or ... it will often fill the bill.
Occasionally you need something better, but you know wham that is
because you are doing something special.
It's then you get out the Zetex catalog ... :-).



    Russel

2011\01\21@195442 by Philip Pemberton

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On 22/01/11 00:20, peter green wrote:
> Fedex on the other hand deliver first and worry about vat/duty/fees
> later.

That's one of the reasons I usually spec FedEx for international transactions. Tektronix used them when I ordered some oscilloscope parts -- I got a customs invoice in the post from FedEx a few days after the parcel was delivered, with full instructions on how to pay.

One quick BACS transfer later, problem solved. Didn't even have to phone them, though I could have (if memory serves, I could have paid by credit card or cheque too).

If you think about it, this makes sense: they know where you live (or at least the final destination of the parcel), so dispatching a horde of debt collectors and bailiffs would be fairly simple. If you don't overthink it, then you get the impression that they actually give a rat's ass and -- shock -- *trust* you not to bugger off without paying.

> Mouser are even better, they use a service called "International
> priority directdistribution" which afaict means mousers european
> subsidary are legally the importer and you just pay everying to mousers
> european subsidary (which is mostly a virtual office afaict but that
> doesn't matter for this).

Seconded. Mouser are my #1 for "weird bits which Farnell don't stock or charge too much for". Case in point: a JAE LVDS cable kit for an LCD display. Cost from Farnell? £30. Cost from Mouser? A tenner. I bought five. Guess who from. Also bought a bunch of the mating connectors, and some Molex 0.4mm nano-pitch dual-row connectors to retrofit to another display (which has a really odd connector you apparently can't buy outside of China).

-- Phil.
TakeThisOuTpiclistEraseMEspamspam_OUTphilpem.me.uk
http://www.philpem.me.uk/

2011\01\21@195556 by IVP

face picon face
> Agreed on the Mouser front, purchasing from them has always
> been a completely painless experience

Same here (New Zealand). Particularly now that Active
Components are their distributor. They amalgamate orders and
those are delivered in bulk from the US, so you pay only local
freight from Auckland, as if it were from mouser.co.nz, not the
US freight from mouser.com

The only slight downside is that you might wait a week, which is
generally no big deal. Otherwise there's RS or Element 14 if it's
urgent

Jo

2011\01\21@202414 by Philip Pemberton

face
flavicon
face
On 22/01/11 00:45, RussellMc wrote:
> On Jellybean FETS.
> Do not use the execrable 2n7002 and friends.
> ONLY good point is voltage rating of 60V
> Otherwise it has pathetic Rdson, gate voltage too high for logic
> driving (not even 5V let alone 3V) etc.

Point taken. I initially bought them because they were listed in the parts list of something I was building. They've sat in my spares box ever since.

I've been using the BSS84 as a jellybean P-ch Enhancement Mode FET; this has a much better gate-threshold voltage of 2V max (typically 1.7V). Though that said, its Rdson is still shockingly poor (10 ohms).

> See my prior rants on nice small FETS.
> Search archives on CES2310 or CETSEMI will probably turn up same.
>
> Buy 1000 and split amongst 10 friends gives 4 cents each

Not listed by Farnell, Digikey or Mouser. If it's not in at least two of them, it doesn't count as jellybean. As nice a part as it is, I'm not speccing it if I can't actually get them...
.... which incidentally is why Maxim-Dallas are on my "not a chance in hell" list... :P

-- Phil.
RemoveMEpiclistspamTakeThisOuTphilpem.me.uk
http://www.philpem.me.uk

2011\01\21@205735 by peter green

flavicon
face

> What are the reasons for this?
>   Firstly if you want something quickly you are likely to get it quicker the more local the supplier is, that is just basic logistics. You can't get anything better than 2-3 days.

But the real issues with ordering from the US to the UK are
1: export regs paranoia. I dunno what the real rules are but DKs insistence on asking export questions for the most mundane of orders and yet not seeming to have a system for doing it other than by hand gets bloody annoying. Next time (which may be a long time in the future) i'm going to try asking procuremtn to fax off the answers with the purchase order and see how that works out.
2: var/duty/brokerage fees. VAT is predictable enough and duty is waived for orders of the sizes prototypers are likely to buy most of the time. but the couriors don't like to tell you what the brokerage fees are until after you have ordered. The exact fees vary by courior but it will likely add another £10 or so to your order. Worse UPS insist on payment of fees/duty/VAT before they will release the package which is I guess acceptable for some buisnesses but can really snarl up with beuracracy in others (basically the problem is does the buisness trust the goods inwards guys to handle money).
3: Shipping costs are often high (as  I say there are exceptions) and/or difficult to determine from the website.
4: many companies won't even give you a price upfront for shipping out of their home areas)
5: Most cards will charge fees for foriegn currency transactions (usually built into the exchange rate) afaict there is no way to determine exactly what a foreign currency transaction on a card will cost other than actually doing it and waiting for the bill (or for it to show up online if you have online banking).
> I do some shipping from US to Europe, does not seem to be problem.
> Also, just checked BC547 on mouser - $0.04 in 100 ea quantity.
> Shipping to UK is $30 (1 - 3 day delivery), shipping in US (New Mexico)FedEx
> overnight - $30.
>
> Maybe I am missing something, but I do not see much difference. Mouser are the one US company I've dealt with that make dealing with them from the UK a pleasure. They give you upfront prices in pounds including everything except VAT (same as most trade orientated suppliers in the UK), they handle collecting and payment of the VAT. They don't seem to ask unnessacery export questions. In general other than the higher threshold for avoiding small order charges (they call them shipping charges but they are essentially a small order charge because they dissapear on larger orders), the size of the small order charge and the slightly longer delivery times they are as painless to deal with as UK based firms.
>  Maybe the
> different experiences people have are due to the size/bureaucracy in the
> organization they work in, rather than distance from
> Mouser/Newark/DigiKey/Farnell/whatever? Beauracracy at our end certainly doesn't help but the fact is trading across international borders (note: for these perposes the EU can be essentially regarded as one country) adds complications.

2011\01\21@225753 by Xiaofan Chen

face picon face
On Sat, Jan 22, 2011 at 2:25 AM, Philip Pemberton <piclistEraseMEspam.....philpem.me.uk> wrote:
> I was recently chatting with a friend, and we got onto the subject of
> 'jellybean' parts, via a discussion on the construction of read-write
> amplifiers for disc drives (seriously!)
>

Just a different perspectives, there are actually "jellybean parts" widely
used in the corporate world as well. In my last job, I think we were
using (and I believe still using) millions of BC846/BC847 and
BC856/BC857. By using the common parts, you increase the
volume of the parts (decrease the cost per part) and reduce the
part count (decrease the part management cost).

In the current job, transistors are used less and less though.


-- Xiaofa

2011\01\22@000702 by speff

picon face
Quoting RussellMc <EraseMEapptechnzspamgmail.com>:


> On Jellybean FETS.
> Do not use the execrable 2n7002 and friends.
> ONLY good point is voltage rating of 60V

Dunno about that. I have found the low gate charge to be an advantage
in some applications.. it can be < 1/10 of devices optimized for low
Rds(on)! It's also multiple sourced and available off the shelf at
the lowest (or close to) price from US distributors compared to other
parts. 20V Vgs rating (30V spikes allowed) is also nice.

> Otherwise it has pathetic Rdson, gate voltage too high for logic
> driving (not even 5V let alone 3V) etc.

It's spec'd at Vgs = 4.5V No good for < 5V.

> See my prior rants on nice small FETS.
> Search archives on CES2310 or CETSEMI will probably turn up same.

Very useful parts, with impressive specs. Hopefully some day they will
be available as easily as 2N7002- they certainly have the potential
to replace the majority of such parts. Rohm has a bastardized 2N7002
that is spec'd to 2.5V Vgs and is cheap (3 cents at DK) . RK7002.  Still relatively high Rds(on), but that's not an issue for many  applications.

{Quote hidden}

>> -

2011\01\22@022155 by Forrest Christian

flavicon
face
On 1/21/2011 5:45 PM, RussellMc wrote:
> Do not use the execrable 2n7002 and friends.
> ONLY good point is voltage rating of 60V
> Otherwise it has pathetic Rdson, gate voltage too high for logic
> driving (not even 5V let alone 3V) etc.
Which datasheet are you looking at.. I just checked 3-4 of them and all of them spec a Vgs(th) of a lot less than 3V...

I'll give you the crappy Rdson, especially at 3V but I've been using them to great success in 3.3V logic for things like led driving...  I will probably switch to something else now I'm moving to surface mount, since I would prefer something which is a bit more energy efficient and is usable in a bit wider set of applications.

-forres

2011\01\22@034946 by Oli Glaser

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face
part 1 1415 bytes content-type:text/plain; charset="iso-8859-1" (decoded quoted-printable)

On 22/01/2011 07:21, Forrest Christian wrote:
> On 1/21/2011 5:45 PM, RussellMc wrote:
>> >  Do not use the execrable 2n7002 and friends.
>> >  ONLY good point is voltage rating of 60V
>> >  Otherwise it has pathetic Rdson, gate voltage too high for logic
>> >  driving (not even 5V let alone 3V) etc.
> Which datasheet are you looking at.. I just checked 3-4 of them and all
> of them spec a Vgs(th) of a lot less than 3V...

Yes, but if you check the conditions, the "typical" Vgs of 2.1V is for an Id of 250uA (at least in the fairchild datasheet) so possibly not the most ideal piece of info to go by.
Better to look at the performance curves to see how much Vgs it takes to turn it on to any reasonable extent - for Vgs 3V it seems you won't get more than 50mA, and for Vgs 4V it's around 400mA. Usable for driving an LED I guess, but would struggle for anything much more demanding at low voltages.
I attached the curves, you should be able to just make them out hopefully - the bottom two lines on the left are 3V and 4Vgs (Id over Vds) First (horizontal) line up on graph is for 0.5A.
The curve in the top left of the right hand graph is for Vgs 4V (Rds over Id) First (vertical) line from the left on graph is for 0.4A. Note they don't even bother with the 3V curve on the right hand graph.. :-)









part 2 20974 bytes content-type:image/jpeg; name="2N7002 specs.jpg" (decode)


part 3 181 bytes content-type:text/plain; name="ATT00001.txt"
(decoded base64)

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View/change your membership options at
mailman.mit.edu/mailman/listinfo/piclist

2011\01\22@040734 by Wouter van Ooijen

face picon face
> So really that just leaves mouser and I'd rather not choose a jellybean
> part that is only availiable (and by available I mean in-stock at the
> time I choose it, not might reappear at some future date) from one
> supplier on my list of acceptable ones. Particulally when that supplier
> is an ocean away.

I buy a lot from Mouser, and for me and for all practical purposes it's based in Munich, Germany. Just like for me Microchip is based in Ireland.

For another EC supplier try http://www.reichelt.de

For non-EC readers: a supplier within the EC does not charge VAT when delivering to another EC country. A supplier outside does not charge VAT either, but the shipping company must do so, which can be a PITA. Having a supplier inside the EC also exempts you from the Digikey-style Spanish Inquisition.

--
Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu

2011\01\22@043301 by Michael Watterson

face picon face

I'm having Deja Vu

Didn't we all have almost this exact discussion last year?

or was it some other mailing list?

I'm sure I remember mentioning that the originals T018 metal can
BC107, BC108, BC109 (vary in gain and Voltage rating)
BC107 -> BC147 "lockfit plastic -> BC547 TO92

And yes in Asia you'd use a 2SCxxxxx instead

I've loads of 2N3904 and BC547, I buy which ever is cheapest on ebay that day.


On 21/01/2011 23:20, Philip Pemberton wrote:
{Quote hidden}

>

2011\01\22@090349 by cdb

flavicon
face


:: Not listed by Farnell, Digikey or Mouser. If it's not in at least
:: two of
:: them, it doesn't count as jellybean. As nice a part as it is, I'm
:: not
:: speccing it if I can't actually get them..

As you are in the UK have you checked out Rapid (rapidonline.co.uk) and the now sadly lacking in depth, Maplin.

Rapid have BC337 @ 5p in singles or 1.7p @500+ VAT to be added. they also have BC547B (VCeo 50V) for 4.3p each.

Colin

--
cdb, RemoveMEcolinspam_OUTspamKILLspambtech-online.co.uk on 22/01/2011
Web presence: http://www.btech-online.co.uk   Hosted by:  http://www.justhost.com.au
 

2011\01\22@100522 by RussellMc

face picon face
> As you are in the UK have you checked out Rapid (rapidonline.co.uk) and the
> now sadly lacking in depth, Maplin.
>
> Rapid have BC337 @ 5p in singles or 1.7p @500+ VAT to be added. they also
> have BC547B (VCeo 50V) for 4.3p each.

Apparently my opining on jellybeans has been discounted.
Or maybe Asian pricing was sought?

A quick look through RS UK shows the items that I mentioned at prices
that i would have thought acceptable enough.

BC807-40 (the SOT23 equivalent to BC327-40
(BC817 == BC337)
4.8p/25
1.5p/5000
In between in between.
NZ readers double GBpence and add a tad to get NZ cents.

BC817-40 6.2 pence/50
No reason for difference.

But, I assume thesere will be other UK suppliers with better prices.
If not, you should emigrate asap.


               Russel

2011\01\22@101323 by RussellMc

face picon face
RS UK

BC337-16. mean beta = 160
BC337-25 - mean beta = 250

337-16  2.6 pence  each / 100
           1.5 pence / 2000


BC327-25
3.7 pence / 100

What price are people in UK wanting/trying/willing to pay for Jellybeans

2011\01\22@105545 by Wouter van Ooijen

face picon face
> What price are people in UK wanting/trying/willing to pay for Jellybeans?

Netherlands: BC547C E 0.009 (ex VAT) @ 1k6

--
Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu

2011\01\22@153729 by RussellMc

face picon face
>> What price are people in UK wanting/trying/willing to pay for Jellybeans?
>
> Netherlands: BC547C E 0.009 (ex VAT) @ 1k6

So the superior BC337-40/BC327-40  should be not much or no dearer
from whatever suppier that is, based on pricing here. No?

2011\01\22@154329 by Olin Lathrop

face picon face
Philip Pemberton wrote:
> If you think about it, this makes sense: they know where you live (or
> at least the final destination of the parcel), so dispatching a horde
> of debt collectors and bailiffs would be fairly simple. If you don't
> overthink it, then you get the impression that they actually give a
> rat's ass and -- shock -- *trust* you not to bugger off without
> paying.

Or will just report to the tax authoroties that you failed to pay, and let
them take care of making things unpleasant for you.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000

2011\01\22@161949 by speff

picon face
Quoting Olin Lathrop <RemoveMEolin_piclistTakeThisOuTspamspamembedinc.com>:

> Philip Pemberton wrote:
>> If you think about it, this makes sense: they know where you live (or
>> at least the final destination of the parcel), so dispatching a horde
>> of debt collectors and bailiffs would be fairly simple. If you don't
>> overthink it, then you get the impression that they actually give a
>> rat's ass and -- shock -- *trust* you not to bugger off without
>> paying.
>
> Or will just report to the tax authoroties that you failed to pay, and let
> them take care of making things unpleasant for you.

They (or to be more precise, their broker, often an internal function)  submit an entry and remit the appropriate taxes in order to have the  shipment released, but generally their terms allow them to bill the  consignor if the consignee does not reimburse them in a timely manner.  Usually the customs release takes place before the physical shipment  arrives in bond at the destination country- and shows up as such on  the tracking. They will also not hesitate to send the bill to a  collection agency, so one way or the other they will likely get paid.

2011\01\22@162219 by smplx

flavicon
face


On Sat, 22 Jan 2011, Olin Lathrop wrote:

{Quote hidden}

You might be able to do that in the US but in the UK the entity that raises the VAT invoice is responsible for collecting the VAT due and passing it on to HM Customs and Excise. The entity does not have the option of witholding VAT because it has not recieved it from it's client.

Regards
Sergio Masc

2011\01\22@164300 by speff

picon face
Quoting smplx <EraseMEsmplxspamspamspamBeGoneallotrope.net>:

>
>
> On Sat, 22 Jan 2011, Olin Lathrop wrote:
>
>> Philip Pemberton wrote:
>>> If you think about it, this makes sense: they know where you live (or
>>> at least the final destination of the parcel), so dispatching a horde
>>> of debt collectors and bailiffs would be fairly simple. If you don't
>>> overthink it, then you get the impression that they actually give a
>>> rat's ass and -- shock -- *trust* you not to bugger off without
>>> paying.
>>
>> Or will just report to the tax authoroties that you failed to pay, and let
>> them take care of making things unpleasant for you.
>
> You might be able to do that in the US but in the UK the entity that
> raises the VAT invoice is responsible for collecting the VAT due and
> passing it on to HM Customs and Excise. The entity does not have the
> option of witholding VAT because it has not recieved it from it's client.

In the US the importer is required to post a bond (or fork over  equivalent value in cash or cash-like securities for months or  longer). The value of the bond is the value of the ENTIRE shipment  PLUS duty and taxes, unless it's a commodity subject to quotas, then  it's THREE TIMES the value of the entire shipment plus duties and  taxes. Brokers and frequent importers use a "continuous bond" for this  purpose. "Trust" is just a name on a bank...

--sp

2011\01\23@032044 by Wouter van Ooijen

face picon face
On 22/1/2011 9:36 PM, RussellMc wrote:
>>> What price are people in UK wanting/trying/willing to pay for Jellybeans?
>>
>> Netherlands: BC547C E 0.009 (ex VAT) @ 1k6
>
> So the superior BC337-40/BC327-40  should be not much or no dearer
> from whatever suppier that is, based on pricing here. No?

This supplier is nedis. BCC337-40 is E 0.019 @ 1k6

--
Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu

2011\01\23@060644 by N. T.

picon face
>> If you think about it, this makes sense: they know where you live (or
>> at least the final destination of the parcel), so dispatching a horde
>> of debt collectors and bailiffs would be fairly simple. If you don't
>> overthink it, then you get the impression that they actually give a
>> rat's ass and -- shock -- *trust* you not to bugger off without
>> paying.
>
> Or will just report to the tax authoroties that you failed to pay, and let
> them take care of making things unpleasant for you.

Truth does matter. Like any n-p-n transistor may have a complimentary
p-n-p equivalent, any rule may have its complimentary equivalent rule.
The rule "read the paper you are signing up" has the complimentary
rule "read the signature you are receiving before having agreed with
it". If you took the sign, this means you agreed with its meaning
regardless of of anything you would write on the paper later. Truth
does matter.
If you agreed, taking the sign, say, to pass your soul to a third
party in the case of your trickery, then, that's it - nobody would
help you later (except, probably, for some from the Dead Sea close
neck-of-the-woods, but that's another story)

2011\01\23@092232 by Olin Lathrop

face picon face
N. T. wrote:
>> Or will just report to the tax authoroties that you failed to pay,
>> and let them take care of making things unpleasant for you.
>
> Truth does matter. Like any n-p-n transistor may have a complimentary
> p-n-p equivalent, any rule may have its complimentary equivalent rule.
> The rule "read the paper you are signing up" has the complimentary
> rule "read the signature you are receiving before having agreed with
> it". If you took the sign, this means you agreed with its meaning
> regardless of of anything you would write on the paper later. Truth
> does matter.
> If you agreed, taking the sign, say, to pass your soul to a third
> party in the case of your trickery, then, that's it - nobody would
> help you later (except, probably, for some from the Dead Sea close
> neck-of-the-woods, but that's another story).

And this outburst is somehow relevant because ... ?


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000

2011\01\23@140043 by Charles Craft

picon face
On 1/22/2011 4:32 AM, Michael Watterson wrote:
> I'm having Deja Vu
>
> Didn't we all have almost this exact discussion last year?
>
> or was it some other mailing list?
>
> I'm sure I remember mentioning that the originals T018 metal can
> BC107, BC108, BC109 (vary in gain and Voltage rating)
> BC107 ->  BC147 "lockfit plastic ->  BC547 TO92
>
> And yes in Asia you'd use a 2SCxxxxx instead
>
> I've loads of 2N3904 and BC547, I buy which ever is cheapest on ebay
> that day.
>
>
>    You're mistaken. We would never rehash a topic on the PIC list.
Now I wonder which C compiler I should be using or if I should be using Assembler instead of C?  :-

2011\01\23@153805 by jim

flavicon
face
Yes, you should


-----Original Message-----
From: RemoveMEpiclist-bouncesKILLspamspammit.edu [piclist-bouncesSTOPspamspamspam_OUTmit.edu] On Behalf Of
Charles Craft
Sent: Sunday, January 23, 2011 1:01 PM
To: Microcontroller discussion list - Public.
Subject: Re: [EE] Jellybean transistors

On 1/22/2011 4:32 AM, Michael Watterson wrote:
{Quote hidden}

Now I wonder which C compiler I should be using or if I should be using Assembler instead of C?  :-

2011\01\23@174250 by RussellMc

face picon face
> And this outburst is somehow relevant because ... ?

Probably because a bit of hum[o|ou]r helps occasionally, and is often fun
regardless.


            R
                [D.S.C.N.O.T.W.' er

2011\01\24@114530 by Sergey Dryga

flavicon
face
peter green <plugwash <at> p10link.net> writes:

>
>
> > What are the reasons for this?
> >  
> Firstly if you want something quickly you are likely to get it quicker
> the more local the supplier is, that is just basic logistics. You can't
> get anything better than 2-3 days.
> <SNIP>

Peter,
Thank you for the explanation.  
Sergey Dryga
http://beaglerobotics.com


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