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VBC of npn transistor in common collector mode

"Rich Grise"

instead

Granted.

:-)

Thanks for the reply.

I have read every entry in this thread, since I am the OP. Elsewhere, I stated that I have observed textbook information on the 2N3903 transistor, specifically, graphical information yielding beta. BF=117, but BR= 0.9.

Another poster offered that V BC (in a common-emitter, inverted topology) was not much different from V BE (in a common-emitter topology).

Another poster emphasized that the saturation voltage of an inverted transistor was lower than the saturation voltage of an uninverted transistor. Specifics were absent. I am not convinced.

I was hoping to see a very low V BC. I'll try this on a bench, at some point in the next couple of weeks. I learned more from this thread, though.

Reply to
John B
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Yeah, I write all my manuals in Courier New, and they are bright and clear and everything lines up. Then the Powers That Be take them and reformat into Times New Roman and then they look like hell.

John

Reply to
John Larkin

I prefer Arial/Helvetica myself, justified left AND right.

Of course I do my illustrations with the appropriate graphics program, NOT with ASCII crap ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
Jim Thompson

I give my doodles to my drafting guy, and he does them in Autocad and exports gif's for figures in manuals.

I wouldn't mind learning a nice line-drawing package, if anybody can recommend one.

John

Reply to
John Larkin

Did you download the PDF from Jims website? its very informative.

FWIW I once accidentally built an inverted CE BJT into a product - the CAD guy flipped the SOT23 (BC847 IIRC). and it still worked. the sw guy noticed something odd, which I promptly ignored (guess what - I dont do that any more. If something looks funny, I now measure the amount of funny and figure out why). 5 months later we did immunity tests, and it failed - BJT had bugger all reverse beta, and couldnt win the pissing match against a coupling clamp. so we wrote a program that analysed the PCB file, looking for flipped parts.

Cheers Terry

Reply to
Terry Given

LOL !

I once 'flipped' an HC something or other ( bus interface ) in Orcad and forgot, and got the ins and outs the wrong way round. It must have been a transparent latch I think. That caused a few hiccups for the s/w guy but he knows his hardware too and twigged it ! Just needed one leg pulled up and a bit of patch wire to get it working perfectly of course.

Graham

Reply to
Eeyore

hardware

get

I once designed a board with half a dozen BC548s as relay drivers. None of them worked, though we could measure a voltage drop and they did get slightly warm. It took a couple of hours to realize that they were OK, except that C and E were inverted from the normal pinout.

- YD.

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Reply to
YD

The easiest one I've ever used is Ashlar's DrawingBoard, followed closely by Autodesk's Autosketch -- both less than $100. Sadly, they are both off the market, probably because they were cutting in to the pricey product sales.

I'm looking for a bonehead simple freebie that I can give out to my students who are just like you and I -- they have absolutely no interest in becoming cadastrial delineators but just need to draw boxes and circles for prototype fabrication. If you come across one, please let me know. Most of the freebies I've found are come-ons for the high priced spread and kill themselves after a short trial period.

Jim

Reply to
RST Engineering (jw)

The most intuitive drafting program I used is called Draft Choice for Windows by Trius. It is fairly primitive, but very easy to use and old shareware (now discontinued). But you can still find copies on the net: ftp://ftp.externet.hu/pub/mirror/sac/graph/dcwin2i.zip

It has all you need for simple mechanical drawings, but you can build symbol libraries to do things like schematics. I have one of these I use a lot.

Reply to
John Popelish

It also is not shareware and expires after 30 days.

Jim

Reply to
RST Engineering (jw)

Mine didn't expire, it just scolded me for not paying for it, after 30 days. After several years, I decided I had done enough productive work with it to pay the $60 or whatever to get rid of the nag. Then they dropped support for it.

Reply to
John Popelish

If it's gone abandonware [*] surf over to

formatting link
and dig out a serial. Be aware that many of the linked sites are scams loaded with p*rn. Turn off java and javascript. Avoid using IE unless security settings are at totally paranoid.

I use it myself for instrumentation diagrams. Then export them as DXF so the autocad guy can get them into the central database.

[*] Not sold nor supported for several years.

- YD.

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Reply to
YD

by

the

students

becoming

prototype

PuhLeez, do not cry until you have tried a search engine and some of the products you find that way.

--
JosephKK
Gegen dummheit kampfen die Gotter Selbst, vergebens.  
--Schiller
Reply to
joseph2k

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