audio recording on IC -help wanted

[Joerg]

Mark Aitchison wrote:

Does anyone make germanium diodes or germanium transistors now? I think
I heard of some expensive modern germanium high frequency devices (but
I'm not sure if that was simply "a few decades old" instead of "many
decades old". There are some advantages with germanium in some
situations, but all the germanium diodes (for instance) I know of are
"new Old Stock" (or "Old Old Stock"!) and not particularly good in many
respects partially because of factors I guess germanium will always
have, but probably largely because the production techniques have
generally improved since then.

If somebody made germanium diodes or transistors today, could they be
much better, closer tolerance, less noisey, etc than before? Are
germanium transistors getting a bum rap simply because they used
techniques that also gave poor silicon transistors back then?

Says their 1N34 Ge Diodes are new but I don't know this company:
http://www.web-tronics.com/1n34.html

Then there is:
http://www.circuitspecialists.com/products/pdf/1n34a.pdf

AFAICT this diode didn't show up on Semtech's parts portfolio so I am
not sure whether they still make them.

--
Regards, Joerg

http://www.analogconsultants.com

 

[David DiGiacomo]

In article <F2dMh.3$5e3.60476@news.sisna.com>,
RST Engineering \(jw\) <jim@rstengineering.com> wrote:

Whatever happened to "Oliver Germanium" and his company?

A remnant of the company still exists, but only makes optoelectronics:

http://www.gpd-ir.com/products.htm

 

[David DiGiacomo]

In article <DbWLh.47$u03.44@newssvr21.news.prodigy.net>,
Joerg <notthisjoergsch@removethispacbell.net> wrote:

Mark Aitchison wrote:

Does anyone make germanium diodes or germanium transistors now?

Says their 1N34 Ge Diodes are new but I don't know this company:
http://www.web-tronics.com/1n34.html

Then there is:
http://www.circuitspecialists.com/products/pdf/1n34a.pdf

Those 2 links are both the same company. My guess is that they buy them
in China:

http://www.alibaba.com/trade/search?Type=&SearchText=germanium+diode&IndexArea=product_en&CatId=0

 

[Joerg]

David DiGiacomo wrote:

In article <F2dMh.3$5e3.60476@news.sisna.com>,
RST Engineering \(jw\) <jim@rstengineering.com> wrote:

Whatever happened to "Oliver Germanium" and his company?


A remnant of the company still exists, but only makes optoelectronics:

http://www.gpd-ir.com/products.htm

It surprised me that there wasn't a Russian company that took over at
least the production of Ge diodes. I could imagine that there would be
sufficient market size for a small enterprise to thrive on that. After
all, Svetlana has done just that for tubes.

--
Regards, Joerg

http://www.analogconsultants.com

 

[Joerg]

David DiGiacomo wrote:

In article <DbWLh.47$u03.44@newssvr21.news.prodigy.net>,
Joerg <notthisjoergsch@removethispacbell.net> wrote:

Mark Aitchison wrote:


Does anyone make germanium diodes or germanium transistors now?

Says their 1N34 Ge Diodes are new but I don't know this company:
http://www.web-tronics.com/1n34.html

Then there is:
http://www.circuitspecialists.com/products/pdf/1n34a.pdf


Those 2 links are both the same company. My guess is that they buy them
in China:

http://www.alibaba.com/trade/search?Type=&SearchText=germanium+diode&IndexArea=product_en&CatId=0

Interesting! So it seems that at least Ge diodes are still made. That
alone can solve a slew of problems.

--
Regards, Joerg

http://www.analogconsultants.com

 

[Lostgallifreyan]

Lostgallifreyan <no-one@nowhere.net> wrote in
news:Xns98FD950D5F27Fzoodlewurdle@140.99.99.130:

I want to do it with a 4 pin IC and some very simple high
level language.

Hmm, I'd settle for 8. Is what I meant... 8 pin DIL or SMT type.
Something easy to work with.

 

[linnix]

Unless more tiny micros are made with 16 bit ADC and DAC on board,
people will always be agonising over expensive analog computation IC's.

If you need 16 bits, the additional chip is the least of your problem.
The noise with D & A circuits on the same board will be so difficult
to deal with, let alone on the same chip.

 

[Lostgallifreyan]

"linnix" <me@linnix.info-for.us> wrote in
news:1174748606.153653.149590@p15g2000hsd.googlegroups.com:

Unless more tiny micros are made with 16 bit ADC and DAC on board,
people will always be agonising over expensive analog computation IC's.

If you need 16 bits, the additional chip is the least of your problem.
The noise with D & A circuits on the same board will be so difficult
to deal with, let alone on the same chip.

Good point... Makes me wonder why I was so often told that the problem is
best solved with code. Analog computation doesn't look so expensive, given
the ease of handling the parts and signals.

 

[krw]

In article <mkud03pg8c2lu5ljpe0oerphik9vcrfupd@4ax.com>,
usenet@imagenoir.com says...

On Sun, 25 Mar 2007 17:38:22 -0400, krw <krw@att.bizzzz> wrote:

In article <ss7d03tpgkqing3bcolbijt79a9sml3a2h@4ax.com>,
usenet@imagenoir.com says...
On Sun, 25 Mar 2007 10:42:33 -0400, krw <krw@att.bizzzz> wrote:

In article <9fac0393nnc4fvfdn4adjaqn1vbni30aa9@4ax.com>,
usenet@imagenoir.com says...
On Sat, 24 Mar 2007 19:32:44 -0400, krw <krw@att.bizzzz> wrote:

In article <46059f7e$0$3748$ba620dc5@text.nova.planet.nl>,
burrynulnulfour@ppllaanneett.nnlll says...
jasen wrote:
On 2007-03-23, Anthony Fremont <spam-not@nowhere.com> wrote:
jasen wrote:
On 2007-03-16, Anthony Fremont <spam-not@nowhere.com> wrote:
TT_Man wrote:
As you said, PIC is king and it is for a reason, they work.

Only if you can get to grips with the appalling op code set..... OK
if you can program in C , I suppose.I can't/won't
I only do assembler on the PIC too. What's wrong with the op-code
set? It's RISC,
no it's not, it has too few registers to qualify.
By whose definition?

Pretty much everyones (with the exception of the PIC fans).

google "what is risc" sometime.



What do you not understand about
"Reduced Instruction Set Computer"?

The term is "Reduce Instruction Set Complexity".

No, it isn't:
http://en.wikipedia.org/wiki/RISC


(A computer with a reduced instruction set???)

No, it's a computer with a set of less complex instructions. The set
can still be quite large and complex (e.g. PowerPC).

A computer with about 30 instructions can be called
a risc computer,as compared to the x86 group with about 500.

Not necessarily. If it has memory reference arithmetic instructions
(e.g. ADD R,<memory&gt it is NOT a RISC processor.

Now if you want to claim that name for something else,
you better explain that, because I think a lot of people
dont agree with you.

Anyone with a passing familiarity with computer architecture will.

I have more than a "passing familiarity" with computer architecture
(nearly 30 years, so far), & I don't agree with you.

Funny, the people who invented the term (and the first example
hardware) do.

You think?
Feel free to post authoritative reference.

First, why don't you tell me what you so object to, since you were
the person I responded to (and have said nothing more than "you're
wrong).

If you'd actually read the whole post, you would've noticed that I've
already posted a link to one reference. You can start there.
Once you're done, you can check:
http://www.google.com/search?&q=define:RISC&oi=glossary_definition
Be sure to let us all know if you manage to find a reference that
agrees with your definition of 'RISC' as meaning: "Reduce Instruction
Set Complexity", raher than "Reduced Instruction Set Computer".

How about Carnegie Mellon University School of COmputer Science?
(http://www.cs.cmu.edu/~mprice/Relationship%20Strategies.txt)

"The most famous approach to these problems is called RISC, short
for Reduced Instruction Set Complexity.

Or, University of Iowa Department of Computer Science
http://www.cs.uiowa.edu/~jones/assem/summer97/notes/16.html

"As a result, processors designed according to the RISC (reduced
instruction set complexity) philosophy..."'

Berkley

http://ptolemy.eecs.berkeley.edu/publications/papers/93/jbuckThesis/t
hesis.pdf

"A RISC (Reduced Instruction Set Complexity) processor, as used in
most workstations today..."

Sun Microsystems:
http://www.freepatentsonline.com/5784588.html

"Many architectures, notably reduced instruction set complexity
(RISC) architectures such as the Scalable Processor Architecture
(SPARC.TM.)..."

MIT
Supertech.csail.mit.edu/papers=3Fkuszmaul.ps

"It has been widely argued that one cannot afford to put any
new =3Facademic=3F mechanisms into state-of-the-art RISC
microprocessors because of the billion-dollar investment that
is put into such microprocessors. That billion-dollar
investment, however, is indicative of the fact that the
=3FReduced Instruction Set Complexity=3F designs have become very
complex indeed."

--
Keith

 

[Lionel]

On Sat, 24 Mar 2007 14:39:09 GMT, Lostgallifreyan <no-one@nowhere.net>
wrote:

Lionel <usenet@imagenoir.com> wrote in
news:0g8a039nv97085vme4997faf4nhuko1uf0@4ax.com:

It's an 8-bit microcontroller it doesn't need that extra stuff ...

Speak for yourself. Since when is A/D resolution not important for
an 8 bitter?

how often is 10 bits too few ?

Quite often. Photography & audio work, just for two popular examples.


Agreed. SOme tasks like laser scanning might call for a small dedicated
controller, and you'd certainly want 16 bits there, especially if colour
mixing was needed.

Even a small task like lin/log conversion, which many on Usenet advise me
was best solved by code, needs to use 16 bits for accuracy over a decent
range.

Indeed.

Unless more tiny micros are made with 16 bit ADC and DAC on board,
people will always be agonising over expensive analog computation IC's. Far
better that we have a small number of cheap standard parts we can learn to
code for.

ADCs & DACs are sold as modules for exactly this reason.

If I knew I could have this, I'd put more effort into learning
it. I don't want to do it with a 40 pin device that needs a diploma to
learn either

Mate, that's electronics for you. If you need those sorts of features,
you need to either pay someone else the big bucks to make you one, or
study long enough to figure out how to make one yourself. (At which
time you'll discover why the first option is so expensive.)

, I want to do it with a 4 pin IC and some very simple high
level language.

I'm tempted to make a joke here about wanting a pony. ;^)

The way things are now, even real experts have argued and floundered over
what best to advise. If more small micros had 16 bit analog I/O built in,
people like me wouldn't even have to ask.

16 bit ADCs (& even DACs) are expensive & difficult to implement at
the best of times. Trying to put them on a microcontroller would be
just about impossible to do at a sane price. (Plus it'd require
multiple, ultra-low-noise, power lines & complex shielding.)

--
W "Some people are alive only because it is illegal to kill them."
. | ,. w ,
\|/ \|/ Perna condita delenda est
---^----^---------------------------------------------------------------

 

[Spehro Pefhany]

On 4 Apr 2007 10:48:10 -0700, the renowned makepcb@qq.com wrote:

GENMA Technology Hong Kong Limited Co. is an export-oriented PCB (
Printed Circuit Board ) manufacturer . We can provide the single-side
PCB, the double-sides PCB and the multi-layer PCB
Contact: Mr. LIU CANFA
Company: GENMA Technology Hong Kong Limited Co.
Address: AiLian B District, LongGang Town
Zip Code: 518121
Phone: 0086-....

Your phone number is in China, not in Hong Kong... it should start
with +852.

A small thing, perhaps, but it's bad to start off with such
discrepancies.

 

[michaelchina]

hi, Joerg Schulze-Clewing :


we have many stock for opa4227,but could you let me know the exact
suffix you interest?
there is have many suffix ,eg. opa4227ua,opa4227pa, we have
opa4227ua,
hope to hear from you .

we have especialized in electronic over 19years.most of our
customers of china distribute repairs line and graduate school ,we
also have plenty of overseas customers,pls find our reference in
enlosed documents.
because we have many years experience for repairs line,so we can
convince you of our service,we hope to establish long-term trade
relationships with you.
since 2001,we became a member of ERAI.

pls give me e-mail if you need any component, sepeciately
stop-producted,hand-find,

MY msn: st_wanggang@msn.com skype : michaelvisual

huandong electronics ltd.

Joergwrote:
Usually I can get by with jelly bean amps but not this time. Offset
should be well under 1mV but most of all the input noise must be
under
5nV/sqrtHz. Supplies +/-15V, TSSOP or SOIC, quad package. The
OPA4227
fits the bill nicely with plenty of margin. Then came the awakening:
Out
of stock at Digikey and Mouser. Same for its faster brother, the
OPA4228. Big red flags went up.

Could the OPA4227 be falling from grace for some reason? If you know

what replaces it I'd appreciate a hint. I am looking around myself
now
but want to pick something that's going to be around for a couple of

decades.

--
Regards, Joerg

http://www.analogconsultants.com

-------------= Posted from Ugroups.com =-------------
---= Fast & Free Web Portal to Usenet Newsgroups =---
-------------= http://www.ugroups.com/ =-------------

 

[Hal Murray]

I have a cable and I send electric current through it. I want to know
the moment when the current has arrived at the other end of the cable.

Can I visualize this moment by using an oscilloscope ?

Sure, as long as your scope is good enough.

The speed of light (in air/vaccum) is 1 ft per ns. How
long are your cables and how good is your scope?

google for >transmission line<


--
These are my opinions, not necessarily my employer's. I hate spam.

 

[Ray King]

Laura,
You are describing the operation of a time domain reflectometer.
Ray



"laura" <laura.brandusan@gmail.com> wrote in message
news:1176232428.504271.314550@w1g2000hsg.googlegroups.com...

Hi,

I have a cable and I send electric current through it. I want to know
the moment when the current has arrived at the other end of the cable.

Can I visualize this moment by using an oscilloscope ?

If the answer is yes, I have another question for a more complex
experiment.

I have a very simple network with 2 nodes (A and B). There are 2
cables which are connecting these nodes. The cables have different
lengths L1 and L2. Assume that L1 is shorter than L2.


I have draw a small picture here:

--A*-------L1---------*B--
| |
| |
|______L2_____|


I apply electric power to this device. Because the cables have lengths
greater than zero I assume that it will take a while until the current
traverse the path from A to B.

More than that, in node A, the current is split in 2, because there
are 2 cables linking A with B. Because one of the cables is shorter I
assume that "a part" of the current arrives earlier (denote this by
moment M1) than the other "part" because it has to traverse a shorter
path. Am I correct ?

The other "part" of the current which has traversed cable L2 will
arrive later in B. Lets denote this by moment M2.

Can I measure these 2 moments by using an oscilloscope?
Or what other options for measurement I have ?

Are there some fluctuations of the electric current at moments M1 and
M2 ?

Are there high precision oscilloscopes for this experiment? Or should
I use very very long cables?

I'm not interested what happens after those moments.


Thanks,
Laura

 

[Arfa Daily]

"Lostgallifreyan" <no-one@nowhere.net> wrote in message
news:Xns9914B02E468DDzoodlewurdle@140.99.99.130...

Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote in
news:46236c94$0$8974$4c368faf@roadrunner.com:

No, you need an exact replacement inverter, specific not so much to the
LCD panel as to the monitor or laptop into which the panel is being
installed.

Agreed. I've rarely worked on those but they are made on custom boards to
fit VERY exacting and confined spaces. Trying to bypass going direct to
the
maker's supplies will cost more (in time, effort, plus cash) than paying
what they ask. So much so that this might be why they charge so much. They
know damn well they can get that money. And they might not cost that much
anyway, they can't fleece a repair person quite as closely and ruthlessly
as they can fleece a member of the public who doesn't know that a Ł90 PSU
is really worth Ł30 or less.

Look at the firm's product line though. To save money they might use the
same custom board in many machines. You might find a low-end version
cheap,
and save money if you don't want a regular supply of bits. Still worth
just
paying up front though, unless you've got the time and attention of a
repairer of laptops and such.

So as I said above, go to the link I posted, and take a look. They have a
very comprehensive inventory of both ccfl tubes and inverters at reasonable
prices, and the exact ones required, may well be available from stock,
without having to try to pry replacements out of the original equipment
manufacturers, whilst not holding a spares account with them ... Even if you
can't see the exact one that you want, a company such as this which
specialises in these spares, could probably cross-reference for you, and
locate a suitable replacement, which may indeed be used in someone else's
product.

Arfa

Arfa

 

[Lostgallifreyan]

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in
news:2sOUh.11269$N94.7789@newsfe4-gui.ntli.net:

Even if you
can't see the exact one that you want, a company such as this which
specialises in these spares, could probably cross-reference for you,
and locate a suitable replacement, which may indeed be used in someone
else's product.

True. CPC are good with that way of working. I guess once any part is often
enough wanting a replacement, there's a market, and the companies might
prefer to sell stocks to other firms to do this, if it saves the original
firm the hassle. I don't actually know how these patterns of trade work,
but it's useful that they do.

 

[conundrum]

On Apr 16, 5:19 pm, Lostgallifreyan <no-...@nowhere.net> wrote:

Barry Watzman <WatzmanNOS...@neo.rr.com> wrote innews:46236c94$0$8974$4c368faf@roadrunner.com:

No, you need an exact replacement inverter, specific not so much to the
LCD panel as to the monitor or laptop into which the panel is being
installed.

Agreed. I've rarely worked on those but they are made on custom boards to
fit VERY exacting and confined spaces. Trying to bypass going direct to the
maker's supplies will cost more (in time, effort, plus cash) than paying
what they ask. So much so that this might be why they charge so much. They
know damn well they can get that money. And they might not cost that much
anyway, they can't fleece a repair person quite as closely and ruthlessly
as they can fleece a member of the public who doesn't know that a Ł90 PSU
is really worth Ł30 or less.

Look at the firm's product line though. To save money they might use the
same custom board in many machines. You might find a low-end version cheap,
and save money if you don't want a regular supply of bits. Still worth just
paying up front though, unless you've got the time and attention of a
repairer of laptops and such.

hey.. are you sure they are blown? i've had success replacing the
microfuses on a few of these, looks like they just die due to age.

the components look like inline SMD inductors but are usually labelled
Fxx or Uxx on the board.
other failure modes are:- dry joints on secondary side, blown
secondary (replace transformer with generic replacement calibrated
using Peak LCR), cracked or burnt piezo transformer (replace), blown
transistors (replace)

i may be able to fix these, if you like you can email me (use subject
line "Inverters on monitors")

hope this helps. -A