audio recording on IC -help wanted

[Watson A.Name - \"Watt Su]

"Florian" <petafrog@evilemail.com> wrote in message
news:m34qko4rip.fsf@tiainen.domain.invalid...

"Damn Dan" <a@a.com> writes:

(snip)

I'd be nice if Honda did provide some kind of solar device or at
least
an external charger... that'd make my life a lot easier.

Wouldn't an external charger be the way to go in any case? In other
posts you've mentioned that 1) driving to work consumes 10% of the
battery charge, and 2) when the battery goes below 50%, the car starts
recharging it, reducing your gas mileage. From this, it seems the
solar
panel is an unnecessary complication -- if you can make a round trip
commute to work with only 80% loss, you're not triggering the recharge
cycle, so why not just top off the battery at home every night from a
wall socket and forget about fickle and expensive solar panel?

From what I've read, the all electric vehicles have to have a massive,
special charger installed at your home. That's not cheap, something
like $5k, plus you then have to pay for the electricity.

(snip)
--
fecit quoque Dominus Deus Adam et uxori eius tunicas pellicias et
induit eos

 

[John Doe]

Since everything else is a not that old Si,
I think you can just put in an 1N4148.

"ed" <edsin222@yahoo.co.in> wrote in message
news:afcb4472.0410270552.df1aa3a@posting.google.com...

Hi,
Can a kind expert soul help me (a novice) to indentify a diode(it is
conducting both ways now) in an old(more than 20yrs.) audio amp.

 

[Watson A.Name - \"Watt Su]

"David Turrell" <dht+usenet@domain.in.sig> wrote in message
news:clpbi4$qjt$1@reader1.panix.com...

I recently purchased an HP Photosmart 435 digital camera. I'm
looking for an A/C adapter that is less expensive than that made
by HP, which costs ~$50 (the camera itself was only ~$100, and I'm
not necessarily going to get another HP camera).

The power requirements for the camera, via A/C adapter, are listed
as 3.3 to 3.7V and 2500mA. I haven't been able to find a generic
adapter that matches those specs.

The closest that Radio Shack seems to have, of their standard,
non-adjustable adapters, is 3V and 500mA. This adapter system has
the advantage of a wide array of tips, the smallest of which (female,
0.7mm interior diameter) would seem to fit the HP camera.

While 3V seems too low, I wonder how the camera is able to make do
with two 1.5V batteries as a power supply!

Thinking about it, the 0.7V diff might be the drop across a rectifier
diode, so maybe all the camera needs is 3VDC.

A Radio Shack universal adapter, which I didn't see, would, based
on the one I have for a radio, have 3, 4.5, 6, etc. volts, which
seems not close enough; and it probably wouldn't give the correct
amperage.

Digi-Key's catalog has a wider range of voltage and amperage choices,
but only matching the voltage, not the amperage. Also, I don't
see a standard tip for them that is small enough for the camera.
A custom-made tip, which they offer, would possibly bring the cost
to where I might as well buy HP's version.

There's always the possibility of a jury-rigged device, but I'm
trying to avoid something that messy.

What substitutions are possible under the circumstances?

You might try using a 3A rectifier diode to drop the 4.5V down to 3.8 or
so volts.

--
David Turrell Domain: panix.com

 

[Watson A.Name - \"Watt Su]

"John Doe" <spam@sucks.com> wrote in message
news:46Tfd.5425$dW.5386@trnddc08...

Since everything else is a not that old Si,
I think you can just put in an 1N4148.

But apparently something is causing the diode to fail. They don't fail
very often, they're very rugged. So there may be something else causing
an overcurrent. In that case, you have to cure the problem or else the
new diode will fail.

You could try using a rectifier instead, such as the 1N4004. They're
very rugged and will dissipate a watt if the leads are close to the
circuit board.

"ed" <edsin222@yahoo.co.in> wrote in message
news:afcb4472.0410270552.df1aa3a@posting.google.com...
Hi,
Can a kind expert soul help me (a novice) to indentify a diode(it
is
conducting both ways now) in an old(more than 20yrs.) audio amp.

 

[Mike Harrison]

On 28 Oct 2004 05:33:38 -0700, bsd_mike@hotmail.com (Mike) wrote:

Is there such a thing as a chip that has a bit of flash and a bit
of regular ram on it?
THanks,
BSD_mike

I think Hitachi, sorry Renesas, do something like this using stacked die in a single package

 

[Michael A. Covington]

"David Turrell" <dht+usenet@domain.in.sig> wrote in message
news:clpbi4$qjt$1@reader1.panix.com...

I recently purchased an HP Photosmart 435 digital camera. I'm
looking for an A/C adapter that is less expensive than that made
by HP, which costs ~$50 (the camera itself was only ~$100, and I'm
not necessarily going to get another HP camera).

The power requirements for the camera, via A/C adapter, are listed
as 3.3 to 3.7V and 2500mA. I haven't been able to find a generic
adapter that matches those specs.

I'm guessing the reason the voltage is higher than the battery voltage is
that there's a protective diode or something. But 3 volts may well work.

2500 mA is a *lot* of current!!!! Does this camera really draw 2500 mA?
If so, it must run down its batteries almost instantaneously.

Does this camera have a flash built in? If so, I'll bet the heavy current
drain is only for charging the flash, and that without flash, you could get
by with a considerably lower-current power supply.

 

[Spehro Pefhany]

On 28 Oct 2004 06:50:40 -0700, the renowned iwicom@yahoo.com (Q Gang)
wrote:

Chin:-

Especially some cheaper white LEDs will lose brightness after a long
time operating near maximum current, but I don't think this is your
problem. (we call it "aging"-- of course they are a year older after a
year whether they are used or not. ;-) )

Zai jian.

I found a strange things in my LEds device.

I made a "Batterless Bicycle Safety Lights" 12 months ago.
(http://www.freelights.co.uk).

The LEDs on the device are opened to the air, sometime raining, water
will touch the LEDs. Few days ago I found the red LEDs not working. I
checked all system, nothings is broken. Then I uses a 3v battery to
test the LEDs, the LEDs are working, but I feel the red LEDs are
little darker than the new LEDs. When I put the red LEDs back to the
device, the red LEDs still not working.

Finally, I change the red LEDs (replaced by 2 new red LEDs), the
system working again.

The problem is: Will the LEDs become older after using a while? Such
as become darker, resistence will go up.....

Someone who are know LEDs well can give me a answer. Thanks very much.

This is very important to me, because I plan to mass manufacturing
this product in low cost. If the LEDs will become older, I have to
change the designs for mass manufacturing. (To be honest, I do not
know how the do the redesign job if the LEDs do get older).

If you are interested see my redesign works for mass manufacturing, go
to:
http://www.helpyou.freewire.co.uk/redesign.html

Thanks for your help.
Chin

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

 

[Dave Platt]

I made a "Batterless Bicycle Safety Lights" 12 months ago.
(http://www.freelights.co.uk).

The LEDs on the device are opened to the air, sometime raining, water
will touch the LEDs. Few days ago I found the red LEDs not working. I
checked all system, nothings is broken. Then I uses a 3v battery to
test the LEDs, the LEDs are working, but I feel the red LEDs are
little darker than the new LEDs. When I put the red LEDs back to the
device, the red LEDs still not working.

Finally, I change the red LEDs (replaced by 2 new red LEDs), the
system working again.

The problem is: Will the LEDs become older after using a while? Such
as become darker, resistence will go up.....

LEDs do tend to lose some brightness over the years. This is a
significant problem for some of the "white" LEDs, which use a phosphor
layer to broaden the spectrum from a blue LED emitter... I've heard
that some of the phosphors "burn out" quite a lot after a year or so
of steady use.

Red and other monocolor LEDs don't use phosphors. They can "age" with
use, but this is normally a fairly slow process... I think they are
usually rated as having lifetime-to-50%-brightness of 100,000 hours or
so, very roughly speaking.

Now, this applies if and only if the LEDs are being used within their
ratings. LEDs do not have a fixed "resistance" - like other diodes,
they conduct very little current at voltages below their "threshold",
and then conduct very high amounts of current once the voltage exceeds
the threshold. Threshold for red LEDs is in the neighborhood of 1.2 -
1.5 volts, depending on the specific color.

LEDs are usually rated for both a maximum continuous current, and an
absolute-maximum pulse current. You can usually get away with running
an LED at current levels higher than its maximum continuous current
*if* you're feeding it pulses with a short duty cycle, but there's an
upper limit beyond which even a short pulse of high current will
either degrade or destroy the LED.

The sharpness of the current-vs.-voltage curve means that it is almost
always necessary to have _some_ form of current control or current
limiting, in order to drive an LED safely.

Also, LEDs are not very tolerant of high inverse voltages. If you
present an LED with a reverse-polarity voltage, it's likely to "break
down" (start conducting current in the reverse direction) at a
relatively low reverse voltage, and I believe I've read that this
tends to degrade the LED junction.

I looked at the "freelights" page, and I wasn't able to see whether
the little magnetic generator contains [1] any form of current
limiting, or [2] any protection against reverse voltages.

If the Freelight doesn't provide a good discharge path for the
"reverse" half of the voltage cycle generated by its little
rattling-magnet dynamo, the reverse voltage (the output of the coils)
is likely to spike up quite high, and I suspect that it'll probably
exceed the inverse-breakdown voltage of the LEDs. This is bad for 'em.

You *might* be able to fix the problems by adding a zener diode right
across the coil. Wire it so that it zeners in the forward direction
when the coil's output voltage rises up high enough that the current
through the LEDs is approaching the safety limit. The zener will also
conduct when the voltage across the coil drops below -0.7 volts (i.e.
one diode drop in the reverse direction) and this should keep the LEDs
safe from excessive inverse voltage.

--
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!

 

[Rich Grise]

On Wed, 27 Oct 2004 20:12:25 -0700, Jamie wrote:

the 3 volt level should be ok since its most likely is putting out more
than 3 volts to start with.

Yabbut, not a 500 mA wart, when the device needs 2500.

Cheers!
Rich

David Turrell wrote:
I recently purchased an HP Photosmart 435 digital camera. I'm
looking for an A/C adapter that is less expensive than that made
by HP, which costs ~$50 (the camera itself was only ~$100, and I'm
not necessarily going to get another HP camera).

The power requirements for the camera, via A/C adapter, are listed
as 3.3 to 3.7V and 2500mA. I haven't been able to find a generic
adapter that matches those specs.

The closest that Radio Shack seems to have, of their standard,
non-adjustable adapters, is 3V and 500mA. This adapter system has
the advantage of a wide array of tips, the smallest of which (female,
0.7mm interior diameter) would seem to fit the HP camera.

While 3V seems too low, I wonder how the camera is able to make do
with two 1.5V batteries as a power supply!

A Radio Shack universal adapter, which I didn't see, would, based
on the one I have for a radio, have 3, 4.5, 6, etc. volts, which
seems not close enough; and it probably wouldn't give the correct
amperage.

Digi-Key's catalog has a wider range of voltage and amperage choices,
but only matching the voltage, not the amperage. Also, I don't
see a standard tip for them that is small enough for the camera.
A custom-made tip, which they offer, would possibly bring the cost
to where I might as well buy HP's version.

There's always the possibility of a jury-rigged device, but I'm
trying to avoid something that messy.

What substitutions are possible under the circumstances?

 

[Watson A.Name - \"Watt Su]

"Michael A. Covington" <look@ai.uga.edu.for.address> wrote in message
news:41804049$1@mustang.speedfactory.net...

"David Turrell" <dht+usenet@domain.in.sig> wrote in message
news:clpbi4$qjt$1@reader1.panix.com...
I recently purchased an HP Photosmart 435 digital camera. I'm
looking for an A/C adapter that is less expensive than that made
by HP, which costs ~$50 (the camera itself was only ~$100, and I'm
not necessarily going to get another HP camera).

The power requirements for the camera, via A/C adapter, are listed
as 3.3 to 3.7V and 2500mA. I haven't been able to find a generic
adapter that matches those specs.

I'm guessing the reason the voltage is higher than the battery voltage
is
that there's a protective diode or something. But 3 volts may well
work.

2500 mA is a *lot* of current!!!! Does this camera really draw 2500
mA?

And a few hundred uF at 330VDC is a lotta capacitor to charge up in a
few seconds. And that takes a lotta current, maybe not forever, but for
quite a few seconds.

If so, it must run down its batteries almost instantaneously.

No, they're 2000 mAh which means they should last for the better part of
an hour. But a camera isn't on very long.

Does this camera have a flash built in? If so, I'll bet the heavy
current
drain is only for charging the flash, and that without flash, you
could get
by with a considerably lower-current power supply.

The LCD and backlight demand a lot of current, too. A lot.

 

[Watson A.Name - \"Watt Su]

"petrus bitbyter" <p.kralt@reducespamforchello.nl> wrote in message
news:Yu3gd.98483$Ye1.32773@amsnews05.chello.com...

"ed" <edsin222@yahoo.co.in> schreef in bericht
news:afcb4472.0410270552.df1aa3a@posting.google.com...
Hi,
Can a kind expert soul help me (a novice) to indentify a diode(it
is
conducting both ways now) in an old(more than 20yrs.) audio amp.
Tandberg TR2025 MB(220v,50Hz).There are 2 similar diodes IN SERIES
in the Power Amp. section(total 4).Its cylindrical(3mm wide,5mm
long)
with 1 tapering(or sudden) step and colour bands-Black,white.light
brown,dark brown,light brown,red.Red colour continues on step and on
other side is golden colour.Its Location:One side of diode is
connected to 2 resistors in series and then to collector of BC 557B.
Other side of the other diode is connected to ground(of
Motherboard).The ground through a resistor connects to collector of
BC
447A.
About a year back,i had replaced one of these with a glass
encased one(1.5mm wide,4mm long-half purple,half orange-red) removed
from the radio section(total 8 on power amp. section,many in radio
section) and the amp. was working(now the output transistors and
others are gone due to 1 speaker coil shorting and some other
causes?).Here is some more info about power amp. section:
1.Transformer supplies about 26v-0-26v with no load.Two 4700 micro
farad electrolytic caps.
2.Output transistors are Motorola BD609 and BD 610(1 pair for each
channel) and BC 848B(?).
3.Other transistors are (per channel): BC 548B, BC 558B, BC447A, BC
557B, C828-C828(emittors joined), BC 547B, BD418(MOTOROLA),2(can't
see
any no.) with small heatsinks and 3 colour bands.

Speakers used are 35 Watts,8 Ohms.
Thanks.
Ed(edsin333@yahoo.co.in)

Ed,

Can't be sure from your description but I guess that diodes are used
for
temperature compensation. If so they are normal Si diodes. As far as I
understand you have a stereo amp with one half fully functioning. So
disconnect the power from the defective one and do some measurements
on the
other. Guess you will find 1.4V across the diodes. Measure the voltage
across a series resistor and you can calculate the current. Should be
enough
information to define replacements for the diodes. But I'm also pretty
sure
it will not solve your problems. Hardly a chanche the defective diode
caused
the problem. It's rather a result. You can continue to compare parts
of the
defective amp with ones of the functioning one. A schematic will be of
great
help. You can order one at
http://www.nrhf.no/nrhf-bank-eng.html
as they pretend to have it available.

petrus bitbyter

If you meant for him to add a resistance in series with the diode,
that's very bad advice. The diodes are probably used for bias on the
output transistors, and if the voltage drop across them increases by
even a small amount, the output transistors will draw excessive current
and will probably fail. They definitely will get very hot, if they
don't fail. So under no circumstances should you meddle with the bias
diodes. If you short them with a milliammeter, the bias on the output
transistors will be reduced and they may have a lot more distortion, but
they won't overheat. But with the reduced current demand on the power
supply, the voltages may change a significantly.

 

[Watson A.Name - \"Watt Su]

"Dave Platt" <dplatt@radagast.org> wrote in message
news:10o2bl9e2h7e2c5@corp.supernews.com...

[snip]

Threshold for red LEDs is in the neighborhood of 1.2 -
1.5 volts, depending on the specific color.

The threshold of IR LEDs is about 1.6 volts, but for red LEDs, it's
about 1.8 to 2.1 volts. That doesn't sound like a lot of difference,
but when you put them in series across a power source, it is very
important.


[snip]

--
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!

 

[Graham W]

Watson A.Name - "Watt Sun, the Dark Remover" wrote:

"Michael A. Covington" <look@ai.uga.edu.for.address> wrote in message
news:41804049$1@mustang.speedfactory.net...

"David Turrell" <dht+usenet@domain.in.sig> wrote in message
news:clpbi4$qjt$1@reader1.panix.com...
I recently purchased an HP Photosmart 435 digital camera. I'm
looking for an A/C adapter that is less expensive than that made
by HP, which costs ~$50 (the camera itself was only ~$100, and I'm
not necessarily going to get another HP camera).

The power requirements for the camera, via A/C adapter, are listed
as 3.3 to 3.7V and 2500mA. I haven't been able to find a generic
adapter that matches those specs.

I'm guessing the reason the voltage is higher than the battery
voltage is that there's a protective diode or something. But 3
volts may well work.

2500 mA is a *lot* of current!!!! Does this camera really draw
2500 mA?

And a few hundred uF at 330VDC is a lotta capacitor to charge up in a
few seconds. And that takes a lotta current, maybe not forever, but
for quite a few seconds.

If so, it must run down its batteries almost instantaneously.

No, they're 2000 mAh which means they should last for the better part
of an hour. But a camera isn't on very long.

Does this camera have a flash built in? If so, I'll bet the heavy
current drain is only for charging the flash, and that without
flash, you could get by with a considerably lower-current power
supply.

The LCD and backlight demand a lot of current, too. A lot.

Another factor not yet mentioned is that the supply *may* be able
to recharge the cells while supplying power for taking more photos.


--
Graham W http://www.gcw.org.uk/ PGM-FI page updated, Graphics Tutorial
WIMBORNE http://www.wessex-astro-society.freeserve.co.uk/ Wessex
Dorset UK Astro Society's Web pages, Info, Meeting Dates, Sites & Maps
Change 'news' to 'sewn' in my Reply address to avoid my spam filter.

 

[Dieter Wiedmann]

ed schrieb:

[Replacement for BD609/610]

http://www.bel-india.com/Website/StaticAsp/prod_semi1.htm

You may use TIP41/42B if load impedance is 8 ohms or more.


Regards,
Dieter

 

[John Doe]

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote
in message news:10o18sqpvij4942@corp.supernews.com...

You could try using a rectifier instead, such as the 1N4004. They're
very rugged and will dissipate a watt if the leads are close to the
circuit board.

The 1N4004 has a higher Vf than the 1N4148,
and so it may not work very well. Rectifier type
diodes are normally used in powersupplies;
setting bias or temp compensation is normally
done with small signal diodes in amplifiers.

Actually, he could probably measure If and Vf,
on a good one, and choose the diode based on
that info. That would probably the best thing.

"ed" <edsin222@yahoo.co.in> wrote in message
news:afcb4472.0410270552.df1aa3a@posting.google.com...
Hi,
Can a kind expert soul help me (a novice) to indentify a diode(it
is
conducting both ways now) in an old(more than 20yrs.) audio amp.

 

[Jim Adney]

On 28 Oct 2004 06:50:40 -0700 iwicom@yahoo.com (Q Gang) wrote:

The problem is: Will the LEDs become older after using a while? Such
as become darker, resistence will go up.....

An LED run at its max current for a year will give off about half as
much light at the end of the year. I suspect that if you run them well
below their maximum current the effect will be much less.

-
-----------------------------------------------
Jim Adney jadney@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------

 

[Ken]

On Fri, 29 Oct 2004 19:45:02 -0500, Jim Adney <jadney@vwtype3.org>
wrote:

The problem is: Will the LEDs become older after using a while?
Such as become darker, resistence will go up.....

An LED run at its max current for a year will give off about half as
much light at the end of the year. I suspect that if you run them
well below their maximum current the effect will be much less.

That's very true.

 

[Jim Adney]

On Fri, 29 Oct 2004 17:46:40 GMT "John Doe" <spam@sucks.com> wrote:

The 1N4004 has a higher Vf than the 1N4148,

I think you'll find that it's actually the other way around. For a
given current, the higher current diode will have a very slightly
lower Vf, because the diode junction is larger.

If you look at the data sheets for enough diodes, you'll see that for
a given % of their rated current they all have about the same voltage
drop. Thus the Vf for a 4004 run at 50% of its rating will have about
the same Vf as the 4148 run at about half its rating.

But the 4004 is a 1A diode while the 4148 is rated at a few tens of
mA.

OTOH, the differences will be quite small.
-
-----------------------------------------------
Jim Adney jadney@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------

 

[Watson A.Name - \"Watt Su]

"John Doe" <spam@sucks.com> wrote in message
news:4mvgd.1719$vJ.993@trnddc02...

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote
in message news:10o18sqpvij4942@corp.supernews.com...
You could try using a rectifier instead, such as the 1N4004.
They're
very rugged and will dissipate a watt if the leads are close to the
circuit board.

The 1N4004 has a higher Vf than the 1N4148,

The 1N4004 series always have lower V drop than signal diodes, in my
experience. Much lower. At a few mA, the V drop is well under .6V.

and so it may not work very well. Rectifier type
diodes are normally used in powersupplies;
setting bias or temp compensation is normally
done with small signal diodes in amplifiers.

Depends on the current thru the diodes.

Actually, he could probably measure If and Vf,
on a good one, and choose the diode based on
that info. That would probably the best thing.



"ed" <edsin222@yahoo.co.in> wrote in message
news:afcb4472.0410270552.df1aa3a@posting.google.com...
Hi,
Can a kind expert soul help me (a novice) to indentify a
diode(it
is
conducting both ways now) in an old(more than 20yrs.) audio amp.

 

[Dieter Wiedmann]

ed schrieb:

A small clarification please....TIP41 or TIP41B

TIP41B/42B.

And for those of Eliott products Transistors.....I intend to build 1
channel without the PCB(i will use a board and wires)...just for
experimentation(my first DIY project).....Hope u will respond.

Ugly design and your vendor does not have fitting transistors.


Regards,
Dieter