audio recording on IC -help wanted

[Charles]

I recently designed a driver for Luxeon III, about 3400 of which are
now being installed on the pyramid shaped Luxor in Las Vegas. I used
the National LM2592-ADJ, with a current feedback for 850 ma Each
driver is for 2 in series, but it can work with 8. Across the 2 in
series is a 220 uf cap. The feedback resistors are not bypassed.
There is also a 5K resistor across each LED pair to make them turn off
quickly. If this is omitted, there is a visible fading "afterglow"
effect as the cap discharges slowly.

The circuit turns on/off in a few millisec. Supply voltage should be
more than 20% over the load voltage (this app uses 42 v anf the "HV"
version of regulator)

Charles

 

In message <no.spam-7621BC.15045616122004@news.verizon.net>, Al
<no.spam@wanted.com> writes

In article <3238e7fb.0412160630.65cdac6d@posting.google.com>,
franzi_gr@gmx.de (FranzM) wrote:

Hallo NG,

beim Test des Fujitsu Controllers MB90F562 tritt bei mir das Problem
auf, dass immer wieder der Pin26 (P01), der zum Flashen benötigt wird,
abraucht, ohne dass der Pin im Test überhaupt berührt wird. Ist
jemandem ein ähnliches Problem bekannt? Ist dieser Pin aufgrund des
inneren Aufbaus des Controllers besonders zerstörungsgefährdet?

Ich weiss nicht. Ubersetzen Sie auf english, bitte.

I can't answer the question, but he wrote:

When testing Fujitsu Controllers MB90F562 I get the problem that pin 26
(P01), which is used for the flash, dies, even though the pin isn't
touched during the test. Has anyone had similar problems? Is this pin
particularly prone to destruction due to the internal construction of
the controller?
--
Graham

 

[Wouter van Ooijen (www.vo]

He said He would RETURN

I hope someone did CALL him, otherwise he will hit a stack underflow.


Wouter van Ooijen

-- ------------------------------------
http://www.voti.nl
Webshop for PICs and other electronics
http://www.voti.nl/hvu
Teacher electronics and informatics

 

[w_tom]

A voltage reversed NiCd is typically due to a weaker cell
being in a stack of other stronger cells when the entire
battery pack is too discharged. Sometimes a negative cell
could be corrected by hitting the cell with higher current in
the reverse direction. On older cells, this would
(theoretically) burn out the reverse section. Then that cell
would be recharged. This technique has not been very
successful for me with newer technology NiCds. But then you
would only be restoring that reversed cell so that operation
can continue until a new battery pack is obtained.

Again, the most probably reason for such a destructive
failure - battery pack was permitted to discharge well beyond
what should have been its lowest limit causing its weakest
cell to become reverse charged.

aurgathor wrote:

A quick check on a 6 pack containing D size Ni-Cad
revealed one with -0.4V, another with -0.1V. I know
that's not a very good thing, so here are my questions:

a) is there some simple circuit that could be used
to prevent this? I'm thinking of a parallel Schottky
diodes, but preferebly with a Vf under 0.1V.
How low can Schottkies go, BTW?
b) how much damage can reverse voltage cause,
and how quickly?
c) what should be terminal voltage when discharing
Ni-Cads? I plan to build a discharger from a battery
holder where they would discharge through some
series diodes and a resistor.

TIA

 

[Dave Platt]

A quick check on a 6 pack containing D size Ni-Cad
revealed one with -0.4V, another with -0.1V. I know
that's not a very good thing, so here are my questions:

a) is there some simple circuit that could be used
to prevent this? I'm thinking of a parallel Schottky
diodes, but preferebly with a Vf under 0.1V.

I don't think you can protect individual cells against this with a
simple circuit. Reverse-biasing tends to occur as a result of
overdischarging a battery pack... one cell drains to zero before the
others, and the others continue to push current through the drained
cell, in effect "charging it backwards". You can't prevent this with
a simple diode protector before some amount of damage occurs, I fear.

The best thing to do is stop discharging the pack when the voltage
drops to a certain threshold. I've heard that 1.0 volts per cell is a
really good place to stop... there's very little useful charge
remaining in the pack at this point, and this is usually high enough
to stop the discharge before any one cell reaches 0 volts.

b) how much damage can reverse voltage cause,
and how quickly?

I understand that it causes the growth of dendrites (thin fingers of
metal) inside the cell, through the separators. In effect, the cell
develops internal short-circuits, which can cause the cell to
self-discharge quite rapidly each time you recharge it.

c) what should be terminal voltage when discharing
Ni-Cads? I plan to build a discharger from a battery
holder where they would discharge through some
series diodes and a resistor.

If you *must* discharge NiCd packs for some reason, don't go below 1.0
volts per cell.

My understanding is that full discharge of NiCds is not actually very
useful at all. Doing it is beneficial only under fairly specialized
conditions, and doing it improperly is more likely to damage the
cells that it is to help.

--
Dave Platt <dplatt@radagast.org> AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

 

[w_tom]

Once some older tech NiCds would suffer a 'memory' problem.
Solution was to complete discharge and then recharge them.
Newer technology NiCds no longer have that problem. No reason
to fully discharge a NiCd other than to put all to a same
discharge state before recharging.

And yes, cells from different manufacturers could have
completely different characteristics. For example, some NiCd
are for high load, short term use. Others are for long term,
slow discharge. Some have longer shelf life and therefore
will discharge faster. So you didn't know so much science
exists in a silly little battery? Check Panasonic for their
application notes on NiCds - if they still exist.

aurgathor wrote:

...
Other then faster discharge, is there any definite advantage of
a constant current discharge?

 

[Dave VanHorn]

Once some older tech NiCds would suffer a 'memory' problem.
Solution was to complete discharge and then recharge them.
Newer technology NiCds no longer have that problem. No reason
to fully discharge a NiCd other than to put all to a same
discharge state before recharging.

Both Nicad and NIMH have this problem, but it's been way overblown, and
confused with other issues. I've seen it specifically in Sanyo HR-AUC cells
where I ran 10-30 cycles to the same discharge voltage at C/2, then
recharged normally at 1C. The result is a slight voltage droop during the
subsequent full discharge at the same voltage point.

And yes, cells from different manufacturers could have
completely different characteristics. For example, some NiCd
are for high load, short term use. Others are for long term,
slow discharge. Some have longer shelf life and therefore
will discharge faster. So you didn't know so much science
exists in a silly little battery? Check Panasonic for their
application notes on NiCds - if they still exist.

Absolutely they do! Nicads work better at low temperatures, and high
discharge rates, than NIMH's do.

Other then faster discharge, is there any definite advantage of
a constant current discharge?

It makes for easy diagnosis of the battery by plotting the time/voltage
curve.
Power out is then easy to calculate, as well as joule output.

 

[Dave VanHorn]

The pack was composed of cells from 2 different manufacturer.

Not a stellar idea. All the cells should not only be of the same exact
type, but they should also be the same age, both in calendar terms, and
"experience".

I took it apart and recharged the reversed ones individually.
No problem as yet, but I'll be replacing all of them soon; until
then I just keep an eye on them.

If they are put back into a pack together, you'll have the same thing
happen.
The reversed ones are permanently damaged now, to some degree, and will have
less capacity than before, making this even more likely.

 

[w_tom]

Just to avoid confusion, my paragraph was discussing NiCds
only; not MiMHs. Some NiCds are for high power, short term
operation. Other NiCds are for long term, low power
operation. Mixing both types in a same stack can cause
problems such as premature NiCd failure. A stack of NiCds
(and NiMHs) should be same manufacturer, date, age, etc (as
another has posted) to avoid problems such as reverse
charging.

Dave VanHorn wrote:

w_tom wrote:
...
And yes, cells from different manufacturers could have
completely different characteristics. For example, some NiCd
are for high load, short term use. Others are for long term,
slow discharge. Some have longer shelf life and therefore
will discharge faster. So you didn't know so much science
exists in a silly little battery? Check Panasonic for their
application notes on NiCds - if they still exist.

Absolutely they do! Nicads work better at low temperatures, and high
discharge rates, than NIMH's do.

 

[The Eighth Doctor]

In article <10t3svlqfs0r0ae@corp.supernews.com>, NOSPAM@dslextreme.com
says...

Can someone help me ID the Hall Effect sensors I'm posting to ABSE?
Thanks.



--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,
@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@
l@u@e@n@t@@


Hello from The Eighth Doctor

You'll have to be more specific. What does that acronym mean? The majority of
Hall Effect Sensors are fabricated by Allegro, then by Honeywell. And then by
Cherry Electronics. (Although that company may not exist any longer.)
----
Gregg C Levine drwho8 atsign att dot net

 

[Watson A.Name - \"Watt Su]

"Gerard Bok" <bok118@zonnet.nl> wrote in message
news:41d4756b.31594749@News.Individual.NET...

On Thu, 30 Dec 2004 17:06:20 +0100, Reinhard Zwirner
reinhard_zwirner@web.de> wrote:

Neil Preston schrieb:

Is there available a DIAC with breakover voltage ratings in the
5-15V range?
Or an equivalent device?

All I've seen so far are in the 50-60v range.

Maybe 2 zeners connected "back-to-back" could work;
"breakover"-voltage
would be [Uz + 0.7] V.

The original message read "... and I need the negative resistance
characteristics ..."

Your solution will mimic a low voltage diac but won't provide the
negative resistance characteristics.

It won't?? Try this.
http://www.freeinfosociety.com/electronics/schematics/zeneroscillator.ht
ml

Or scroll down to the third one here
http://www.geocities.com/CapeCanaveral/Lab/5185/circuit.html

Now I've tried it, and was unsuccsssful, but I've read that other people
have been able to get it to work. I've also hear that it helps to heat
the zener up with a soldering iron to roast it and make it change its
characteristics.

--
Kind regards,
Gerard Bok

 

[Gerard Bok]

On Thu, 30 Dec 2004 20:07:20 -0800, "Watson A.Name - \"Watt Sun,
the Dark Remover\"" <NOSPAM@dslextreme.com> wrote:

Is there available a DIAC with breakover voltage ratings in the
5-15V range?
Or an equivalent device?

All I've seen so far are in the 50-60v range.

Maybe 2 zeners connected "back-to-back" could work;
"breakover"-voltage
would be [Uz + 0.7] V.

The original message read "... and I need the negative resistance
characteristics ..."

Your solution will mimic a low voltage diac but won't provide the
negative resistance characteristics.

It won't?? Try this.
http://www.freeinfosociety.com/electronics/schematics/zeneroscillator.ht
ml

Or scroll down to the third one here
http://www.geocities.com/CapeCanaveral/Lab/5185/circuit.html

Now I've tried it, and was unsuccsssful, but I've read that other people
have been able to get it to work. I've also hear that it helps to heat
the zener up with a soldering iron to roast it and make it change its
characteristics.

The instructions basically say: fry the part beyond being a zener
diode.
The question is, if this circuit --if operating at all-- is using
a zener diode to operate or is exploiting idiosyncratic behaviour
of overstressed part. And still: I'd like to see the negative
resistance display in the graph.

But either way: it's not a diac. (Rememer, the nice tiny device
that fires reliably, even in the absence of a soldering iron

Happy New Year !

--
Kind regards,
Gerard Bok

 

[carl mciver]

Methinks that this is teflon tape, which is hi-temp stuff until it burns
and outgasses some nasty stuff. Very slippery stuff. Almost feels oily,
and you have to grab it just right to handle it. Trying to recall who makes
this kind of tape.... Scotch? Permatex? Permacell?


"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> wrote in message
news:dtaht05qlifl41hr615lormhskv65tlgbc@4ax.com...
| Hi,
|
| here's a photo:
|
| https://www.pendrypowdercoatings.com/shop/images/Hi-Temp%20Tape.JPG
|
| They call it "Hi-temp tape". It's sold as "masking tape" for powder
| coating (so presumably it's good to 350°F or more), and I'd like to
| track the specs down for another potential application.
|
|
| Best regards,
| Spehro Pefhany
| --
| "it's the network..." "The Journey is the reward"
| speff@interlog.com Info for manufacturers:
http://www.trexon.com
| Embedded software/hardware/analog Info for designers:
http://www.speff.com

 

http://www.globalspec.com/FeaturedProducts/Detail?ExhibitID=11492

 

[Al Clark]

Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> wrote in
news:dtaht05qlifl41hr615lormhskv65tlgbc@4ax.com:

Hi,

here's a photo:

https://www.pendrypowdercoatings.com/shop/images/Hi-Temp%20Tape.JPG

They call it "Hi-temp tape". It's sold as "masking tape" for powder
coating (so presumably it's good to 350°F or more), and I'd like to
track the specs down for another potential application.


Best regards,
Spehro Pefhany

I'm not sure what your application is but there is a tape made for masking
pcbs for wave soldering called Kapton tape (3M - Scotch 5413 Polyimide Film
Tape) It is good for continuous use up to 500 F.

You can find it at DigiKey.


--
Al Clark
Danville Signal Processing, Inc.
--------------------------------------------------------------------
Purveyors of Fine DSP Hardware and other Cool Stuff
Available at http://www.danvillesignal.com

 

[Spehro Pefhany]

On 2 Jan 2005 18:28:01 -0800, the renowned larwe@larwe.com wrote:

http://www.globalspec.com/FeaturedProducts/Detail?ExhibitID=11492

Thanks, Lewin,

They appear to be polyester tape with silicone adhesive, so nothing
new. I suppose they soften along with the polyester powder at the
~400°F cure temperature, but the silicone adhesive keeps them from
sticking permanently. I don't think I've seen the translucent green &
blue colors before.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Spehro Pefhany]

On Sun, 02 Jan 2005 19:06:55 -0800, the renowned John Ings
<nodamned@spam.org> wrote:

On Mon, 03 Jan 2005 02:35:02 GMT, Al Clark <dsp@danvillesignal.com
wrote:

https://www.pendrypowdercoatings.com/shop/images/Hi-Temp%20Tape.JPG

They call it "Hi-temp tape". It's sold as "masking tape" for powder
coating (so presumably it's good to 350°F or more), and I'd like to
track the specs down for another potential application.

I'm not sure what your application is but there is a tape made for masking
pcbs for wave soldering called Kapton tape (3M - Scotch 5413 Polyimide Film
Tape) It is good for continuous use up to 500 F.

You can find it at DigiKey.

Where I worked we used Kapton in vacuum chambers where satellite
equipment was being toasted by quartz lamps. It's pretty good stuff.
For our applications it not only had to resist heat but also not
outgass in vacuum. It's a yellow brown in color though.

I agree that Kapton (polyimide) tape is excellent stuff (aircraft
disasters notwithstanding). I'm trying to find something not *quite*
as good (but hopefully substantially cheaper).

Another brand in use at the same facility that's blue like the sample
you posted the URL to is sold by this outfit:
http://www.tycoadhesives.com/site/content/tape_search.asp

Lots o' tapes on that site, including some quite unusual ones. Thanks.
I don't see anything that's high temperature and that color (though
the color is immaterial with polyester).


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

http://www.globalspec.com/FeaturedProducts/Detail?ExhibitID=11492

They appear to be polyester tape with silicone adhesive, so nothing
new. I suppose they soften along with the polyester powder at the

Looked like polyimide according to the manufacturer's site.

Do you want to use this as a stencil for anodized aluminium instrument
panels?

 

[Spehro Pefhany]

On 2 Jan 2005 19:39:48 -0800, the renowned larwe@larwe.com wrote:

http://www.globalspec.com/FeaturedProducts/Detail?ExhibitID=11492

They appear to be polyester tape with silicone adhesive, so nothing
new. I suppose they soften along with the polyester powder at the

Looked like polyimide according to the manufacturer's site.

They are non-specific on the colors vs. materials. I think if it's
polyimide it's going to be amber, if it's polyester it could be
anything.

Do you want to use this as a stencil for anodized aluminium instrument
panels?

High temperature electrical insulation.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Martin H. Eastburn]

Spehro Pefhany wrote:

On Sun, 02 Jan 2005 19:06:55 -0800, the renowned John Ings
nodamned@spam.org> wrote:


On Mon, 03 Jan 2005 02:35:02 GMT, Al Clark <dsp@danvillesignal.com
wrote:


https://www.pendrypowdercoatings.com/shop/images/Hi-Temp%20Tape.JPG

They call it "Hi-temp tape". It's sold as "masking tape" for powder
coating (so presumably it's good to 350°F or more), and I'd like to
track the specs down for another potential application.

I'm not sure what your application is but there is a tape made for masking
pcbs for wave soldering called Kapton tape (3M - Scotch 5413 Polyimide Film
Tape) It is good for continuous use up to 500 F.

You can find it at DigiKey.

Where I worked we used Kapton in vacuum chambers where satellite
equipment was being toasted by quartz lamps. It's pretty good stuff.
For our applications it not only had to resist heat but also not
outgass in vacuum. It's a yellow brown in color though.


I agree that Kapton (polyimide) tape is excellent stuff (aircraft
disasters notwithstanding). I'm trying to find something not *quite*
as good (but hopefully substantially cheaper).


Another brand in use at the same facility that's blue like the sample
you posted the URL to is sold by this outfit:
http://www.tycoadhesives.com/site/content/tape_search.asp



Lots o' tapes on that site, including some quite unusual ones. Thanks.
I don't see anything that's high temperature and that color (though
the color is immaterial with polyester).


Best regards,
Spehro Pefhany
http://www.3m.com/us/mfg_industrial/indtape/masking/html/prodlit.jhtml

A selector guide of sorts -

Look over the class 1 masking tapes - the 2693 is a good start. There are
several to check - and make price cut based on volume of total world market.
Maybe the 2380 in class II. (Cheaper by class I bet)

Then searching for powercoat :
3M™ Composite Bonding Tape 8905, 10 in x 72 yd, 4 per case
[click to enlarge]

Clean removing high temperature silicone adhesive and tough
non-slivering polyester backing makes this tape a popular
choice for powder coat paint masking. 6.6 mil (0.17 mm)
total thickness.


3M Id : 70-0063-1697-3 << this one looks like a baking at 350F for 5 hours
and up to 400F...
GTIN(UPC/EAN) : 0 00 21200 55208 3

Don't know the prices - have to check them out.
Martin

--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer oldtree@pacbell.net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder