audio recording on IC -help wanted

[Eeyore]

dizzy wrote:

Eeyore wrote:

If the central heating is on, then you are, by definition, needing extra
heat. The heat output from lighting will mean that the room thermostat (or
radiator valves) will turn off that bit sooner.

Not really.

The heat from most lamps hangs around at ceiling level. It does sod all to warm
a room.

Wrong.

Not wrong.

Graham

 

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[Terminal Crazy]

In article <1IYzi.26282$Db6.22805@newsfe3-win.ntli.net>, ian field
<dai.ode@ntlworld.com> wrote:

The September issue was supposed to include a free LED driver PCB - mine
didn't!

Contact the Mag directly, they should have other copies & should be able to
mail one out.

--
Terminal_Crazy

Mitch - 1995 Z28 LT1 M6 terminal_crazy@sand-hill.freeserve.co.uk
Lancashire England http://www.sand-hill.freeserve.co.uk/terminal_crazy/

 

[Bob AZ]

On Jul 19, 11:21?am, "N Cook" <diver...@gazeta.pl> wrote:

eg 5007 presumably week 07 of 52 in year 2005
JRC seems to use this convention of reversing post-millenium dates - do
others ?

Many decades ago 5007 stood for year 1950. Work 07. And usually this
was based on a 50 work week year.

I will have to monitor date codes more closely to see if the 50 work
week thing is still true.

Bob AZ

 

[Joerg]

ian field wrote:

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news3TIj.4014$p24.3690@nlpi061.nbdc.sbc.com...
ian field wrote:
"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:evQIj.26778$Ch6.8240@newssvr11.news.prodigy.net...
ian field wrote:
"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:7%bIj.20887$xq2.6498@newssvr21.news.prodigy.net...
While contemplating a new design I was looking around for tapped
inductors and 455kHz IF filters which also can be used as such. Got a
sticker shock. Even at quantities they can't be had under 75c. Ouch!
Also, not many brands. Digikey doesn't have any, Mouser only carries
one (Xicom).

Are LC IF filters finally going lalaland? I remember them to be really
cheap. They had to, because even a $10 radio contained half a dozen of
those.

--
Regards, Joerg

http://www.analogconsultants.com/
Try: http://www.abacus.co.uk/jkcm/Products/Passive

Look for the passive product matrix PDF above the top LH corner of the
main panel.

Its a large group of companies, so it may have a facility local to you.
Thanks, Ian, but that's the usual suspects. They only have ceramic
resonators.

--
Regards, Joerg

http://www.analogconsultants.com/
Nothing here:
http://www.toko.co.jp/products/en/coils/index_variable_e.html then?
That's just inductors sans tap, only adjustable. Toko does have filters
but the selection has shriveled to stuff like these 3.58MHz chroma
filters:

http://www.toko.co.jp/products/en/filters_lc/fss_e.html

I usually need more extreme tap ratios (or impedance ratios). But even
these 3.58MHz will likely go lalaland soon because analog TV is gone for
good in the US next year. It's going to be a 100% cut, there won't be any
analog stations left by the end of February. Meaning no chroma carriers
either.

--
Regards, Joerg

http://www.analogconsultants.com/

Some of the PDF sheets I downloaded from that page contain a notice inviting
customers to enquire about detailed specifications - have you tried doing
that?

Not yet. I am looking for something that's available off the shelf and
where there is a chance that it's going to stay that way for a decade or
two. Else I can't really use it in a new design.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

While contemplating a new design I was looking around for tapped
inductors and 455kHz IF filters which also can be used as such. Got a
sticker shock. Even at quantities they can't be had under 75c. Ouch!
Also, not many brands. Digikey doesn't have any, Mouser only carries one
(Xicom).

Are LC IF filters finally going lalaland? I remember them to be really
cheap. They had to, because even a $10 radio contained half a dozen of
those.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[legg]

K.A.Pullen's Conductance Curve Design Manual is up
and running on the Magma/Primus Server.

http://www.magma.ca/~legg/CCDM/CCDMp000iii.html

This will be of interest to valve / vacuum tube hobbyists.

Standardized characteristic curves for 63 tube structures with
equivalent lists and indexes.

RL

 

[Mook Johnson]

I need some 49.9K - 51k resistors that will see peaks of 500V across them
for a few seconds.

I'm looking for some resistors that are reasonable in size that are rated
for greater than 750V that is readily avaialble.

Something like a MS220 form Caddock would work but it needs to be readily
available. Last itme I used these on a project they had a 6 week lead.

 

[Bogo Joe]

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[RealInfo]

Hi all

I am looking for mini pushpull audio output transformer , exactly like the
same type used in vintage transistor
portable radion in the 60 and 70's .

Does any one know good siurces for this ?

Thanks
EC

 

[msg]

Albert Manfredi wrote:

"Mr.T" <MrT@home> wrote in message
news:46933bf7$0$6925$afc38c87@news.optusnet.com.au...


"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:46933246.64CB7FA6@hotmail.com...

4500K is still somewhat blue for most peoples' taste.


You must really hate daylight then!


Daylight for artificial lighting is rather annoying.

<snip>

For some of us in cold climates with little daylight during the winter
season, seasonal affective disorder can be a serious problem; bright
daylight wavelength lighting at night and in the morning is necessary
as a therapy.

BTW, why is this thread crossposted to so many newsgroups? I suggest
removing r.a.t., s.e.b. and s.e.t.a. at least for followups.

Regards,

Michael

 

[DaveC]

Have simple detector circuit that specifies 1N21B diode. That diode is
20-plus years old and obsolete. Looking for current equivalent, possibly (but
not necessarily) smt.

Are these useable in place of a 1N21B for 2.4 GHz detection?:

<http://tinyurl.com/6g62bu>

<http://tinyurl.com/62fqnv>

Suggestions welcome.

Thanks,
--
DaveC
me@bogusdomain.net
This is an invalid return address
Please reply in the news group

 

[Boris Mohar]

On Sat, 30 Jun 2007 10:13:17 -0500, clifto <clifto@gmail.com> wrote:

John Robertson wrote:
Looking for a few (5ish) 140/450VDC low ESR caps as used for Strobe
light power supplies. These have two 10/32 bolts on raised studs on one
end (Radial-like) and are series 36D POWERLYTIC.

Just a thought: the flash units in throwaway cameras have nice 120 uF
330V caps on them, most likely low ESR. The ones I'm looking at are
Rubycon and marked "PHOTO-FLASH".

Throwaway cameras use throwaway parts.

--

Boris Mohar



--
Posted via a free Usenet account from http://www.teranews.com

 

[TT_Man]

<mad.scientist.jr@gmail.com> wrote in message
news:1194625195.526723.308650@o3g2000hsb.googlegroups.com...

Can anyone explain how to (or where to find instructions) build an
accurate linear slide potentiometer of 100k, 150k or 1M ohm? I am
looking to make one with a physical length would be from 2" to 10". I
have seen little exercises where you can draw a pencil line on paper
and connect electrodes to it, and it acts as a resistor, so I am
thinking that building a slide pot might be possible with the right
materials. Any info appreciated...

How about a flat rack gear driving a circular gear mounted on a 10 turn pot?

Easy mechanics.... cheap solution.......

 

[Tim Wescott]

gearhead wrote:

Hi all, I'd like to help out some friends on an antique motorcycle
forum that have a 6 volt regulator project. One of them built a
regulator on perfboard and posted the schematic. It has a couple of
things I'd tweak, but it works.
The main challenge: his regulator design doesn't incorporate current
limiting. Even the original relay-style mechanical regulators
incorporated current limiting, because the generators required it.
Somebody on the forum suggested the zxct1009, but it only comes in
surface mount which means we can't rejigger the existing perfboard
project to include the new chip. It would mean having a custom-
printed circuit board, and soldering techniques perhaps a little too
demanding for somebody building his first circuit -- which probably
describes a lot of the guys on the forum.
pdf of the circuit:
http://www.hydra-glide.com/phpBB2/download.php?id=1173
I've tried to find a through-hole component that fits the bill, but
can't seem to come up with anything just right. I saw the micrel
MIC5021, but it supposedly operates on 12 volts and up.
http://www.micrel.com/_PDF/mic5021.pdf
Now, perhaps they make that statement on the datasheet because the
chip actually also has a voltage doubler and the high side drive needs
that kind of voltage to turn on a mosfet, and it's possible the chip
itself will actually run on a much lower voltage. But the datasheet
doesn't say anything to this effect. Has anybody used the MIC5021 and
know if it might actually turn on at say 5 volts or perhaps know of
any other through hole chips for current sensing?

This is just a suggestion, but consider the circuit below. If the
transistors are well matched Vchg should come pretty close to Vgen/10 +
47 * 0.02 * Ibatt -- and you can jigger your component values around to
change the numbers. You'll _probably_ be able to make this work OK with
any two unmatched (but like part-number) PNP transistors, like 2N3904's,
but you'd do better to get a matched pair (DigiKey has some Zetex parts
that would do, if there are any through-hole ones).

Try this out with SPICE before you run with it: I just threw it down off
the top of my head, it's not exactly like anything I've done before nor
is it tested at all.


Vgen ___ Vbatt
o-----o---|___|---o-----o
| | ----->
| 0.02 | Ibatt
.-. .-.
| |100 | |100
| | | |
'-' '-'
| |
| |

| |
|---o---|

/| | |\
| | |
| | |
Vchg | '-----o
o-----o |
| |
.-. .-.
| |4.7K | |47K
| | | |
'-' '-'
| |
| |
=== ===
GND GND
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)


--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

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[Pieter]

On Sat, 13 Oct 2007 15:32:07 -0700, Marra
<cresswellavenue@talktalk.net> wrote:

On 5 Oct, 20:41, Pieter <dit3_werkt_ook_n...@hotmail.com> wrote:
On Mon, 24 Sep 2007 06:04:33 -0700, Rap...@gmail.com wrote:
Hello
I have a circuit with a BC857B where the transister gets destroyed.
I am a litle out of ideas. When mounted on the board i have seen
arround 150 transistors out of 1800units where destroyed.
The transistor in first place seems shorted between collector and
emitter, the ressistance is between 5 to 250 Ohm.
The funny part is both "diodes" in the transistor can be measured
from
base. And the one with 250Ohm i have tried to activete in the circuit

Notice that the resistance means nothing here, it is just a value your
multimeter comes up with depending on current it uses. Use the 'diode'
measurement of the meter, it will send a constant current through the
diodes and show the resulting voltage. That should be 0.6, and not
working in the opposite direction.

and the transistor seems to react and make lower ressistance between
collector emitter. (so in fact it looks like a normal working
transistor with a build in ressitor of 5-250ohm between collector and
emitter)

So maybe that really is so.





The product has been produced for several years with out problems,
they started in earlier this year..
I have got several transistors decapped, so there seems not to be any
burned inside the transistor and the boundings where ok. I have only
seen the chip from the top, and collector emitter is in top of each
other.
The product is assambled by proofesinel production house and been
both reflow and wave soldered (only wave soldered on the bottom side)
Another funny things are there are 2 of the same transistor on the
board, we are only seeing one of them with error so far.
I have measred the currents in the circuit it seems ok.
There has been tried to change transistor vendor, and there has been
seen the same problem, but only 25 of 1800 with same error.
Does anyone have a auggestion to the error, or seen similar ??
Best Regards
Rapzak

Hi,

I think that your transistor gets partially damaged. As if it starts
conducting at some places in the transistor. There can be many causes,
but here are two plausible ones:

1) A high voltage peak gives a local breakdown in the chip, and makes
a bad conducting channel. This could be caused by for example this
transistor controlling the coil of a relay without damping diode or
snubber network. Did you change the a relay with biult-in diode to one
without? Or changed it to a relay woth other inductance?

2) SOA, Safe Operating Area. The maximum power of a transistor is not
only defined by current, voltage and power, but also by SOA.
Especially at higher voltages, current must be lower than expected.
Even when voltage, current and power are all within specifications,
the transistor may fail. What happens is that locally at higher
voltages, the p-n layer gets warmer, starts condcuting more there,
gets warmer etc etc. This may also cause your problems. Maybe you are
using different supply voltages? Or maybe your design was already
outside specification, but now it is used in another environment where
it is used differently? Notice that as this problems occures at higher
voltages, it may happen when you do NOT load the circuits.

Pieter- Hide quoted text -

- Show quoted text -

If the transistor is being destroyed then:
1/ The voltage across CE is too much.
2/ The BE voltage is getting too high.
3/ Could be a static discharge problem and they are destryoed by
handling but unlikely.
4/ The transistor has been put in the circuit the wrong way around.

http://www.ckp-railways.talktalk.net/pcbcad21.htm

And some more:
Negative BE voltage (non-conducting direction), can already break down
at 5V and actually destroy the transistor depending on the components
around it.
High temperatures, power must be limited at higher temperatures.
Too high collector current.
Too high emitter current.
Too high base current.

So there can be many more causes, Safe Operating Area can even limit
the maximum current of power transistor to half the current you would
expect. And this also applies to low power transistors.

Notice thet exchanging C and E will not destroy the transistor but it
will give you a transistor with low quality, low gain etc.

Pieter

 

[gearhead]

On Apr 8, 1:30 pm, "petrus bitbyter"
<pieterkraltlaatdit...@enditookhccnet.nl> wrote:

"gearhead" <nos...@billburg.com> schreef in berichtnews:e66fa9e8-d621-4ba3-8c47-fc5752b3f045@m36g2000hse.googlegroups.com...





Hi all, I'd like to help out some friends on an antique motorcycle
forum that have a 6 volt regulator project.  One of them built a
regulator on perfboard and posted the schematic.  It has a couple of
things I'd tweak, but it works.
The main challenge:  his regulator design doesn't incorporate current
limiting.  Even the original relay-style mechanical regulators
incorporated current limiting, because the generators required it.
Somebody on the forum suggested the zxct1009, but it only comes in
surface mount which means we can't rejigger the existing perfboard
project to include the new chip.  It would mean having a custom-
printed circuit board, and soldering techniques perhaps a little too
demanding for somebody building his first circuit -- which probably
describes a lot of the guys on the forum.
pdf of the circuit:
http://www.hydra-glide.com/phpBB2/download.php?id=1173
I've tried to find a through-hole component that fits the bill, but
can't seem to come up with anything just right.  I saw the micrel
MIC5021, but it supposedly operates on 12 volts and up.
http://www.micrel.com/_PDF/mic5021.pdf
Now, perhaps they make that statement on the datasheet because the
chip actually also has a voltage doubler and the high side drive needs
that kind of voltage to turn on a mosfet, and it's possible the chip
itself will actually run on a much lower voltage.  But the datasheet
doesn't say anything to this effect.  Has anybody used the MIC5021 and
know if it might actually turn on at say 5 volts or perhaps know of
any other through hole chips for current sensing?

That Micrel chip is not a current sensor, it is a mosfet driver. Looking for
a highside current sensor, try the MAX4374. A ZXCT1008 or ZXCT1009 may be
even better. But I doubt you to need that special (and expensive) chips.

Can't be sure what current you want to limit, but usually the field current
is limited to limit the output voltage of the generator. Which in turn
prevents the battery from being overloaded. This is exactly what the circuit
of your schematic is supposed to do. Just use R1 to set the correct voltage.
For a 6V lead-accid battery this will be about 6,9V. So even for fully
loaded battery the voltage should never exceed that value. You may have to
take some voltage loss accross D6 into account which is about 0.2V for this
particular diode.

petrus bitbyter- Hide quoted text -

- Show quoted text -

Current limiting protects the generator, not the battery.

 

[Michael Black]

On Mon, 21 Apr 2008, JeffM wrote:

Michael Black wrote:
[...]google is[...]a web interface [to Usenet] that also allows posting.
But they do a lousy job of telling users that,

Amen. Something like this should be a click-thru requirement.
http://www.google.com/search?q=cache:E_t0eevlNNAJ:groups.google.com/support/bin/answer.py?answer=46492%26useful=0%26show_useful=1%26comment=+Terms+Usenet

making them believe they are posting to a "google group".
INdeed, their interface is now biased in favor of their "google groups",

That's arguable. ISTM if Google was truly biased
TOWARDS those people accessing Usenet thru Google Groups,
they would try hard to make that experience a spam-free one.

"Biased towards their 'google groups'", as in the groups that are local

only to google.

The fact that I just confused you is my point. Google uses "google
groups" to refer to their own groups, and their access to Usenet, and
use the very same interface for both. That's what muddles it.

When google bought up the dejanews archive, "google groups" only meant
Usenet. But then they added their own "google groups" that started
muddling things. I can't remember if those came with the arrival
of the new interface, "google groups 2" or somewhat before.

But when they introduced "google groups 2", the interface, the default
became no quoting of what you are replying to (and hiding the bit about
quoting some level down). A web based forum has less need of quoting
since you can instantly scroll up the webpage and find the message being
replied to. But that doesn't necessarily apply to usenet.

The hiding of email addresses is another thing that's biased towards
their "google groups". Given that the rest of the world can see those
email address, and archive them if desired and even parse them to make
up an email spam list, there's not a lot of good reason to hide the email
addresses. But, the "google group" users don't have their messages
leaving google, so the hiding of their email addresses at google actually
does something.

When "google groups 2" was introduced, they actually forget (or didn't
care) that people could suddenly reply to old messages, not just months
old but even decades old. And combined with the lack of default quoting,
that caused a spew of replies to messages that nobody could find the
originals to. Then it became clear they were replying to really old
messages. Again, that's less of a consideration for "google groups",
indeed given they were just started at the time, any message could
be current rather than decades old. Google eventually reverted to
the previous policy for Usenet, of not allowing posting to messages
older than 4 weeks old, but it took a few weeks at least. They wouldn't
have made that mistake if they were thinking of Usenet rather than
their own "google groups".

So long as google treats their local groups as if equal to Usenet,
the muddling will continue, and the blundering is just so much easier.

Michael

 

[Wimpie]

On 8 abr, 22:34, gearhead <nos...@billburg.com> wrote:

On Apr 8, 10:03 am, Tim Wescott <t...@seemywebsite.com> wrote:



gearhead wrote:
Hi all, I'd like to help out some friends on an antique motorcycle
forum that have a 6 volt regulator project. One of them built a
regulator on perfboard and posted the schematic. It has a couple of
things I'd tweak, but it works.
The main challenge: his regulator design doesn't incorporate current
limiting. Even the original relay-style mechanical regulators
incorporated current limiting, because the generators required it.
Somebody on the forum suggested the zxct1009, but it only comes in
surface mount which means we can't rejigger the existing perfboard
project to include the new chip. It would mean having a custom-
printed circuit board, and soldering techniques perhaps a little too
demanding for somebody building his first circuit -- which probably
describes a lot of the guys on the forum.
pdf of the circuit:
http://www.hydra-glide.com/phpBB2/download.php?id=1173
I've tried to find a through-hole component that fits the bill, but
can't seem to come up with anything just right. I saw the micrel
MIC5021, but it supposedly operates on 12 volts and up.
http://www.micrel.com/_PDF/mic5021.pdf
Now, perhaps they make that statement on the datasheet because the
chip actually also has a voltage doubler and the high side drive needs
that kind of voltage to turn on a mosfet, and it's possible the chip
itself will actually run on a much lower voltage. But the datasheet
doesn't say anything to this effect. Has anybody used the MIC5021 and
know if it might actually turn on at say 5 volts or perhaps know of
any other through hole chips for current sensing?

This is just a suggestion, but consider the circuit below. If the
transistors are well matched Vchg should come pretty close to Vgen/10 +
47 * 0.02 * Ibatt -- and you can jigger your component values around to
change the numbers. You'll _probably_ be able to make this work OK with
any two unmatched (but like part-number) PNP transistors, like 2N3904's,
but you'd do better to get a matched pair (DigiKey has some Zetex parts
that would do, if there are any through-hole ones).

Try this out with SPICE before you run with it: I just threw it down off
the top of my head, it's not exactly like anything I've done before nor
is it tested at all.

Vgen ___ Vbatt
o-----o---|___|---o-----o
| | -----
| 0.02 | Ibatt
.-. .-.
| |100 | |100
| | | |
'-' '-'
| |
| |
| |
|---o---|
/| | |\
| | |
| | |
Vchg | '-----o
o-----o |
| |
.-. .-.
| |4.7K | |47K
| | | |
'-' '-'
| |
| |
=== ===
GND GND

I've done plenty of scheming about how to do it with discretes. But
like you said, I'd still want to use a chip in the end, to get matched
transistors. Pairs and arrays, I see ony surface mount, including
zetex.
If I have to go that way, might as well use the ZXCT1009F in SOT-23
with pins 1.9 mm apart according to the diagram. Almost a tenth of an
inch, could probably solder it right onto the pads of a perfboard, eh?

Hello,

When you buy about 10 general purpose PNP transistors from one batch,
you will probably find several transistors that are within some mV
with same Ic. When you design the 2 transistor current sensor at low
bias current, self heating can be neglected and it saves you from
soldering SMD devices like NXP's BCM857. When matching is impossible,
you might add a trimmer potentiometer for nulling.

best regards,

Wim
PA3DJS
www.tetech.nl
please remove abc from the address