Driver to drive?

[John Woodgate]

I read in sci.electronics.design that amdx <amdx@worldnet.att.net> wrote
(in <WlfHd.43849$w62.24865@bgtnsc05-news.ops.worldnet.att.net&gt about
'Sub for BC549C', on Tue, 18 Jan 2005:

This transistor has a high beta.
Trying to build a mic amp and several designs use this transistor.

If this is for your stethoscope project, the beta is probably not very
critical. But you don't even say which country you are in, so how can
anyone suggest a substitute that you will be able to get?

Where did you find the design with the BC549C? If it's on the web, a URL
would be helpful. Otherwise, can you put the circuit diagram on a web
page? Or on a.b.s.e?
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Rick Thompson]

On Tue, 18 Jan 2005 14:55:47 -0500, Chuck Harris
<cf-NO-SPAM-harris@erols.com> wrote:

There is no reason that you have to pay RedHat. The amount you pay is
purely for their support. You can get the entire distribution from a
number of places. One is www.tux.com

Are you sure? The RedHat site gives no hint that you can run the
current RHs without paying. The free distribution is FCx, which is
different.

BTW, www.tux.com sells tuxedos...



Rick

 

[mc]

Forget about paying Ł70/wk, though. It's 10 years since I've been in
shared houses, but 300-400 pcm was the going rate then. There's an alt
Cambridge newsgroup somewhere - ask in there.

cam.misc I think is what you have in mind.

 

[John Popelish]

amdx wrote:

This transistor has a high beta.
Trying to build a mic amp and several designs use this transistor.
Thanks
Mike

I think the 2N5089 is pretty close (high gain, low current, low
noise).
Compare:
http://www.semiconductors.philips.com/acrobat_download/datasheets/BC549_550_4.pdf
http://www.fairchildsemi.com/ds/2N/2N5089.pdf
--
John Popelish

 

[Joerg]

Hello Chris,

This is usually spec'd in the data sheet. For logic it is often called
"DC output diode current" under abs max ratings. If in doubt, I'd
contact an applications engineer at the manufacturer.

For lines going to the outside world extra Schottkys are often
indispensable, considering the moment of truth when the test lab guy
puts on his cowboy hat and wields that big honking ESD zapper gun.

Regards, Joerg

http://www.analogconsultants.com

 

[richard mullens]

Pig Bladder wrote:

"Kevin Aylward" <salesEXTRACT@anasoft.co.uk> wrote in message


You *have* to steal them off someone else.


Apparently, Mr. ailwierd is of the "Women are property" school of naziism.

Nonsense, it's the first bit of sense I've read here in ages.

 

[Pooh Bear]

amdx wrote:

Totally normal for a modern silicon device.

Trying to build a mic amp and several designs use this transistor.

Indeed they do these days..

Before the BC549, the BC184(C) would have been typical.

What's your problem with the BC549 ? It's in full production from
multiple suppliers. You may not actually need the C grade - but I guess
from your question that your experience isn't sufficient to work that
out. The C grade is often used by companies standardising on parts. I
actually normally use the B grade.


Graham

 

[Pooh Bear]

John Popelish wrote:

amdx wrote:

This transistor has a high beta.
Trying to build a mic amp and several designs use this transistor.
Thanks
Mike

I think the 2N5089 is pretty close (high gain, low current, low
noise).
Compare:
http://www.semiconductors.philips.com/acrobat_download/datasheets/BC549_550_4.pdf
http://www.fairchildsemi.com/ds/2N/2N5089.pdf
--
John Popelish

Watch out for the reversed BCE connections.

NF is also specified @ 10k ohms for the 2N5089 but 2k ohms for the BC549. Suggesting
a lower noise voltage for the BC549 - although this may or may not be important
depending on the placement of this part in the overall circuit. Neither part is
really suitable for genuine low noise amplificiation of typical low-Z mics as a first
stage device. You'll need a pnp part for that with low intrinsic resistance such as
the 2SA1084.


Graham

 

[Rhyanon]

Yer sooo anal retentive.

And easy to yank around.

"keith" <krw@att.bizzzz> wrote in message
newsan.2005.01.18.01.11.05.758884@att.bizzzz...

On Mon, 17 Jan 2005 07:16:46 -0600, Rhyanon wrote:

Slow learners, eh?

Top posters? Yeah.

--
Keith

 

[keith]

On Tue, 18 Jan 2005 21:35:28 -0600, Rhyanon wrote:

Yer sooo anal retentive.

Nope. I shit better looking things than you every day. No problems here.

And easy to yank around.

Not that you'd have a clue.

--
Keith

 

[Rhyanon]

Anyway, that's beside the point; I mean, come on -- suckin' dick for half
a dime. SAD ...........

"keith" <krw@att.bizzzz> wrote in message
newsan.2005.01.18.03.01.23.705738@att.bizzzz...

On Mon, 17 Jan 2005 20:59:52 -0600, John Fields wrote:

On Mon, 17 Jan 2005 20:18:17 -0500, keith <krw@att.bizzzz> wrote:

The record shows that she wasn't a top-poster, so you have a lot of
learning before you're worth a that nickel (it is *nickel*, twat).

---
The element is 'Nickel', the coin a 'Nickle'.

Sorry. :-(

Umm, not according to Mr. Webster (though your spelling is listed as a
deviant ;-):

http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=nickel&x=0&y=0

2 a (1) : the U.S. 5-cent piece regularly containing 25 percent
nickel and 75 percent copper (2) : the Canadian 5-cent piece b : five
cents

--
Keith

 

[Randy McLaughlin]

"Rhyanon" <pissoff@uberbitch.com> wrote in message
news:10ufl0nomjh3qb9@corp.supernews.com...

HA - ha!! And now you're even being a hypocrite! I wonder if this was a
record speed for dweeb - yanking?

"John Fields" <jfields@austininstruments.com> wrote in message
news:tk3eu0d9kjlgopb1rucmtjp3jk8d6pouk1@4ax.com...
On Tue, 11 Jan 2005 20:41:35 -0600, "Rhyanon" <pissoff@uberbitch.com
wrote:

I expect you to do what I compel you to do, dumbass. Now dance.

---
I compel you to expect the unexpected, pigfart.

I don't dance, don't ask me. And stop top posting.

--
John Fields

Please don't cross post.

Randy

 

[John Larkin]

On Fri, 14 Jan 2005 08:23:54 -0700, Jim Thompson
<thegreatone@example.com> wrote:

On 14 Jan 2005 07:19:39 -0800, "Tim Shoppa" <shoppa@trailing-edge.com
wrote:

[Tungsten filaments, CdSe photocells, MOV resistor with exponential
curves]

Those are all interesting implementations, but they aren't a new
mathematical identity like Max was asking for. They're just varying
implementations of the exponent/logarithmic circuit.

One interesting thing about the CdSe photocells is that they're very
linear in electrical response while being nonlinear in optical
response. That has very real advantages in many applications.

Tim.

CdSe? I've heard of CdS, although I can recall, as a kid, dismantling
Selenium rectifiers and using a single plate as a photocell.

...Jim Thompson

CdSe cells are similar to CdS but have faster response. They were once
popular as choppers, among other things. HP made a cool DC voltmeter
that went down to 1 mV full-scale (or 1 uV? I forget) that used them
to chop and demodulate, all clocked by a synchronous motor and a
spinning slotted disc in front of a lightbulb.

When *I* was a kid, I generally used photomultiplier tubes, or
germanium transistors with the tops of the cans cut off.

I made an IR detector once that used a flashlight reflector and a
black-painted germanium transistor, measuring just the Ge leakage
current. Now that I think about it, it probably accidentally used
thermal runaway as a positive-feedback gain enhancement mechanism. It
could easily detect the heat of your hand from six feet away.

John

 

[Terry Pinnell]

"amdx" <amdx@worldnet.att.net> wrote:

This transistor has a high beta.
Trying to build a mic amp and several designs use this transistor.
Thanks
Mike
Which do you mean? The circuit you link

http://www.hut.fi/Misc/Electronics/circuits/micamp.html
specifies a BC547B

BC547B
------
European equivalent: BC337
USA: 2N5818
Old Radio Shack: 276-2009

BC549C
------
European equivalent: BC548C-->BC547C-->BC239
USA: 2N5818
Old Radio Shack: 276-2009

But both could be replaced by *hundreds* of other possibles of similar
spec. Here's the data for the BC547B:

Package Vcb(max) Vce(max) Veb(max) Ic(max) Tj(max) Ptot
TO92 50V 45V 6V 100mA 150C 500mW

Ft(min) Cob(max) Hfe(min) HfeBias
200MHz 4.5pF 200 2mA


--
Terry Pinnell
Hobbyist, West Sussex, UK

 

[Rhyanon]

Was THAT supposed to be grammatically proper? Heh. Read your lil posty poo
aloud and realize how idiotic you sound. Oh, and thanks for dancing to my
tune, going to all this effort because I snapped my fingers at you. Dipshit.

"keith" <krw@att.bizzzz> wrote in message
newsan.2005.01.19.03.59.43.354729@att.bizzzz...

On Tue, 18 Jan 2005 21:43:00 -0600, Rhyanon wrote:

Sorry, your dorkspeak isn't relevant.

Because you can't understand English is somehow my problem?

Your whining,
^^^^^^^ The fact that you're stupid doesn't mean I whine.

puling
^^^^^^ You couldn't your own weight (if you could spell), which I
understand is considerable.

and histrionics
^^^^^^^^^^^ You are a froot-loop!

are what currently fuels my momentary
^^^^^^^^^ attention span

, capricious
^^^^^^^^^^ we all knew that. Tell us something new!


minimal interest
^^^^^^^^^^^^^^^^ It seems you're interested. You're hooked. Though
perhaps "minimal" is intended to explain your intelligence?

in you.

Ah, it does care about me!

I wish to see how long I can yank you around before you run crying to
your killfile blankie, shitferbrains.

Nope, I'm man enough to ignore you without need of a silly killfile, kid.
You think you're something new? Hell, even the commie PoS Bemmelman
doesn't have a place in my killfile. ...like you, too easily ignored.

I'll pick on you for this, I'll
pick on you for that.

Keep picking... Whatever floats your boat.


Nothing personal; you just happen to be among the
rank and file of the sucking masses. Surely you're *used* to it by now?

You're a stupid top-poster, and you'll still be ugly in the morning. So?

--
Keith

 

[Rhyanon]

Day late and dollar short, dipshit. Your lamely attempting to ape the
tactics already successfully employed upon you only makes your self -
humiliation complete.


"John Fields" <jfields@austininstruments.com> wrote in message
news:qsqsu09sqrmq9vs7sb3tjh4kb68vk0tss5@4ax.com...

On Tue, 18 Jan 2005 21:37:41 -0600, "Rhyanon" <pissoff@uberbitch.com
wrote:

WAHAHAHA!! Two replies? For a _correction_ nonetheless? Priceless! You
are a
true weeny!

---
Just can't stop yourself, can you?

--
John Fields

 

[Rhyanon]

Backpedal away, dipshit -- you lose and you know it. HAH.


"John Fields" <jfields@austininstruments.com> wrote in message
news:jspsu0hkl0r76rfapmsl7q1r5d2i00h35h@4ax.com...

On Tue, 18 Jan 2005 21:36:49 -0600, "Rhyanon" <pissoff@uberbitch.com
wrote:

And *now* I have you spending time thinking up lame crap in which to
insert
my Net nym. hee hee hee! And better yet, you underscored my previous
assertion!!

---
Nothing of the kind; just a little exercise to keep me amused, and of
course I _expect_ derision from the likes of you, who because of their
limited mentality know no better way to become visible than to foment
skirmish after skirmish with their betters.

--
John Fields

 

[John Fields]

On Tue, 18 Jan 2005 21:45:20 -0600, "Rhyanon" <pissoff@uberbitch.com>
wrote:

You're a 'deviate' , not 'deviant'... Or at least, you fantasize you are....

---
Well, through your eyes, a deviant must be someone who is so totally
unlike you that they _aren't_ knuckle-draggers.

--
John Fields

 

[Nicholas O. Lindan]

Interestingly, dating services don't work very well. If two peoples'
objective profiles are matched - height, weight, careers, interests,
all that usual stuff - it doesn't at all indicate that anything will
click when they meet. It's far more effective to let them just sniff
one anothers' used t-shirts; HLA antigen matches (or, actually,
mismatches) are what makes for romance.

Hot Damn! I'm going into business: "Dating Service and Underwear Exchange".

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

 

[John Larkin]

On Wed, 19 Jan 2005 14:58:54 GMT, "Nicholas O. Lindan" <see@sig.com>
wrote:

Interestingly, dating services don't work very well. If two peoples'
objective profiles are matched - height, weight, careers, interests,
all that usual stuff - it doesn't at all indicate that anything will
click when they meet. It's far more effective to let them just sniff
one anothers' used t-shirts; HLA antigen matches (or, actually,
mismatches) are what makes for romance.

Hot Damn! I'm going into business: "Dating Service and Underwear Exchange".

The ultimate dating service would only need blood samples.

John