audio recording on IC -help wanted

[Costas Vlachos]

"E Draisma" <draisma1@xs4all.nl> wrote in message
news:3f4b2f15$0$49116$e4fe514c@news.xs4all.nl...

Dear all,

First of all I tried the simplest approach suggested by some of you:
. ___ Imax
. 8-10V o-------|___|------o------>-----o ~1.4V
. R |
. |
. |
. V 1N4001
. -
. |
. |
. V 1N4001
. -
. |
. |
. ===
. GND

This didn't work; the 8-10V power supply also stepped down to approx 2V.
As
a result the amplifier connected to the MP3 player (and to the same power
supply) stopped working.
Next I tried the LM317 (see below & see attachment) This seemed to work as
it gave me 1,5V.

What??? The 8-10V supply went down to 2V??? What value of R did you use??? I
hope you didn't take R to mean 1 Ohm!!! I tried the above circuit in the lab
and it worked for me (gave me from 1.3V to 1.4V for a few tens of mA of
current which the MP3 player should draw). You must have done something
wrong here.

THE PROBLEM: (See figure 1) When the MP3 player is powered by the LM317
(instead of AAA battery) I hear a lot of noise; I guess it must be ripple
(?) amplified by the amplifier.
I then tried figure 2, but still there was a lot of noise.
QUESTION: does anyone of you know how I should get rid of the noise?

I can't see the binary newsgroups from here, so can't see your figures. Try
to add a capacitor at the output if there isn't one already. See the LM317
data sheet for recommendations. There is a circuit in there that has
improved ripple rejection - that may do the trick. Is your 8-10V adequately
filtered?

Hope you sort out the problem, good luck.

Costas

 

[William P.N. Smith]

"E Draisma" <draisma1@xs4all.nl> wrote:

This didn't work; the 8-10V power supply also stepped down to approx 2V.

Tell us more about this 8-10V supply, what is it and what's it's
current rating?

Next I tried the LM317 (see below & see attachment) This seemed to work as
it gave me 1,5V.

THE PROBLEM: (See figure 1) When the MP3 player is powered by the LM317
(instead of AAA battery) I hear a lot of noise;

When you run the amplifier off the 8-10V supply and the MP3 player off
a 1.5V battery, do you still get this noise?

Try bypass caps on the input and output of the LM317.

--
William Smith wpns@compusmiths.com N1JBJ@amsat.org
ComputerSmiths Consulting, Inc. www.compusmiths.com

 

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frankhaussmann@web.de wrote:

Sorry, but I belive there was a missunderstanding. I am looking for
Superluminesence-Diodes which are (simplified)constructions of a LED
mounted next to a "laser" structur for amplifing light power without
receiving coherence.

I see: you are not looking for a light source, but for an optical
amplifier for 675 nm visible red light that is capable of delivering 3
mW output power. I have no experience with this :-(.

Presumably these things work like a subcritical laser.

I hope somebody else can help you.

Martin.


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[Bob]

Try a tantalum capacitor across the output. Maybe 2 or 5 uf.

--
-------------------------
Bob La Rocca
Lindenhurst, NY
"E Draisma" <draisma1@xs4all.nl> wrote in message
news:3f4b2f15$0$49116$e4fe514c@news.xs4all.nl...

Dear all,

First of all I tried the simplest approach suggested by some of you:
. ___ Imax
. 8-10V o-------|___|------o------>-----o ~1.4V
. R |
. |
. |
. V 1N4001
. -
. |
. |
. V 1N4001
. -
. |
. |
. ===
. GND

This didn't work; the 8-10V power supply also stepped down to approx 2V.
As
a result the amplifier connected to the MP3 player (and to the same power
supply) stopped working.
Next I tried the LM317 (see below & see attachment) This seemed to work as
it gave me 1,5V.

THE PROBLEM: (See figure 1) When the MP3 player is powered by the LM317
(instead of AAA battery) I hear a lot of noise; I guess it must be ripple
(?) amplified by the amplifier.
I then tried figure 2, but still there was a lot of noise.
QUESTION: does anyone of you know how I should get rid of the noise?

Thanks again!
Eibert




**My 1st Question was**: For an art project I need to build a small 1,5V
power supply to power a
small MP3 player. (replace a 1,5V AA battery)
Available is 8-10V DC. I know a little bit about electronics, enough to
build a simple schematic


Use the LM317 adjustable regulator. Connect two 470 ohm resistors in
parallel (235 ohms) from output pin to the adjust pin, and a 47 ohm
resistor from adjust pin to ground. Or use a 100 ohm trimmer pot
instead of the 47 ohm to give you some adjustment. With the pot, the
lowest you can go is 1.2VDC, and the highest less than 2V, maybe 1.8V.
If the current is high, then mount the LM317 to a heatsink.

 

[Fred Abse]

On Tue, 26 Aug 2003 07:13:14 +0100, Dan Fraser wrote:

Electrolytic Capacitors have fluid too. Corrosive too.

Yes, though not in such ample quantities as batteries, which the OP
mentioned were in there.

Not as likely to leak out with time, either, IME.

--
Then there's duct tape ...
(Garrison Keillor)
nofr@sbhevre.pbzchyvax.pb.hx

 

[Walter Harley]

"Fred Abse" <excretatauris@cerebrumconfus.it> wrote in message
newsan.2003.08.26.18.46.24.776358.884@cerebrumconfus.it...

On Tue, 26 Aug 2003 07:13:14 +0100, Dan Fraser wrote:

Electrolytic Capacitors have fluid too. Corrosive too.

Yes, though not in such ample quantities as batteries, which the OP
mentioned were in there.

Not as likely to leak out with time, either, IME.

They leak out in a big hurry if you put enough juice across 'em But
I've definitely seen old boards with oozing electros where they got too
hot - the PCB's in cheap TV's and computer monitors usually have some.
Never seen enough ooze to actually run off the board and into another box,
though.

 

[William Rees]

Thanks for the info Rob,

I am hoping to get some of the originals but if needs be I'll have to
substitute, the one you have flagged looks good , also MTP50N06V's. Both of
these unfortunately are TO220 whereas the MTH40N06's are TO247 so a little
surgery may be needed!
Thanks again
regards
Bill

"Robert Monsen" <postmaster@BulkingPro.com> wrote in message
news:3QU1b.180175$cF.61531@rwcrnsc53...

I'm sure it would be possible to substitute something. The NTE cross
reference didn't have a replacement, but it did have a replacement for a
STP30N06L, which may be the right replacement.

http://www.nteinc.com/specs/2900to2999/pdf/nte2986.pdf

Regards

"William Rees" <billrees@ntlworld.com> wrote in message
news:kIs1b.262$L4.467587@newsfep1-win.server.ntli.net...
RS have discontinued these. A friends needs some (2 ) to fix an old bit
of
kit on his fishing boat. If you have some you'd be willing to sell on
please
email me with price etc
thanks Bill Rees (alt email bill.rees@virgin.net)


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[Greg]

Perhaps there is an oscillator corresponding to your needs at
Oscilloquartz SA www.oscilloquartz.com

 

[Spehro Pefhany]

On Sat, 30 Aug 2003 09:31:42 GMT, the renowned Robert Baer
<robertbaer@earthlink.net> wrote:

Greg wrote:

Perhaps there is an oscillator corresponding to your needs at
Oscilloquartz SA www.oscilloquartz.com

I bought a roll of 1/2 wide Kapton tape from Digikey.

Ouch, they're an expensive source.

How many inches do you need, and what do i stick it on to keep it
decent and useable?

How about aluminum foil (for the OP)?

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

 

[Zak]

Andras Tantos wrote:

Let me make my statement more precise: comparable featured A/D - succesive
approximation and flash - converters need a couple of elements that are at
least as precise as the LSB precision of the converter.

OK. So we have a successive approximation converter. Measure a bit, then
subtract that (by using D/A to "the other comparator input"), and
continue until done.

Then someone comes along and invents the flash converter. Not many bits,
but fast. Conceptually works with a nice ladder, and a comparator for
each ladder step. A 6 bit output needs 64 comparators and some logic
fumbling to generate a number.

Then, someone things about a way to make a wider fast converter. Take a
flash converter, and follow it with a very accurate D/A. This generates
the upper bits of the output. The output from the D/A is subtracted in
the analog domain from the input, and this residual is converted again
(with another converter, or the same one). The output bits combine.

Now, the flash converter can be reduced to a 1 bit converter. Note that
the A/D needs not be that accurate, as long as the D/A is. And the
scaling to the next stage needs to be accurate. Probably very accurate,
as the inaccuracies multiply.

Now, it may be possible to do clever things on the digital side. Idea:

- use only a single stage that loops until done.
- set the gain to 'next stage' a bit low. The digital side will
compensate for this after calibration.
- the output from the 1 bit D/A affects only the scale, not linearity.

It is a bit of a 'cycle of reincarnation' in action. Hmmz.. given that 1
bit D/A probably is not hard to do consistently, and that we have a
calibration step anyway, this could very well be pipelined too. OTOH a
somewhat wider flash converter is not that expensive either and the
nonlinearity will be of a rather forgiving type, with the imperfections
of the second converter neatly interpolating in the imperfections of the
first one.


Thomas

 

[Fred Abse]

On Thu, 28 Aug 2003 02:35:09 +0100, Walter Harley wrote:

They leak out in a big hurry if you put enough juice across 'em

Yup, got sprayed only the other day

--
Then there's duct tape ...
(Garrison Keillor)
nofr@sbhevre.pbzchyvax.pb.hx

 

[Robert Baer]

Spehro Pefhany wrote:

On Sat, 30 Aug 2003 09:31:42 GMT, the renowned Robert Baer
robertbaer@earthlink.net> wrote:

Greg wrote:

Perhaps there is an oscillator corresponding to your needs at
Oscilloquartz SA www.oscilloquartz.com

I bought a roll of 1/2 wide Kapton tape from Digikey.

Ouch, they're an expensive source.

How many inches do you need, and what do i stick it on to keep it
decent and useable?

How about aluminum foil (for the OP)?

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

Also have some aluminum foil tape, as well as (a fair amount of)
yellow mylar tape at 1/2 wide, as well as 1 inch wide glass and very
small amount of teflon tape.
The copper tape is wider, 2 versions: embossed (1") and flat (1.25").
Dew dat hep?

 

[Watson A.Name - "Watt Sun]

In article <o3l5lv88d3mj71cuf0e0goirjf666cfcej@4ax.com>,
snovotill@hotmail.com mentioned...

On 31 Aug 2003 17:23:40 -0700, Winfield Hill <whill@picovolt.com
wrote:

Second, and perhaps as important, the current-mirror has serious
problems with Early-effect and with base-current errors. A much
better circuit is possible with the same or less parts count, as
I've shown several times here in s.e.d. in years past.

Thanks,
- Win

OK here is the fixed circuit using Pulse Frequency Modulation supply
based on Hysterisys feedback.

http://members.shaw.ca/novotill/LedHystFeedbackPfm/index.htm

It goes into full regulation when Vbat exceeds LED Vf by 100mV.

That stupid analog current mirror circuit of mine actually has a good
minimum voltage in the upper current source, but terrible in the lower
mirror part. That is unavoidable is it not? I think this is because
you can't get any gain out of a transistor with a mere 100mV bias
accross the C-E "junction". The reason for the base current errors is
because I needed to stay with NPN transistors because I was using a
transistor array IC. What a pile of rubble.

Why come you didn't throw in a 100 uF bypass cap across the battery?
Might help a bit.

I got on Hosfelt Electronics web site and ordered a couple c-notes
worth of parts. Most of that was in the submini toggle switches,
which were half the price I could find them at other places. The
DPDTs were only $.65. Cheap. For some odd reason, the SPDT were
more, but still cheap, $.89. I got 4 of the Mueller Kelvin Clips, and
those were $7.50 each, so that added up, too. But I think I nickled
and dimed too many pretty colored ultrabright LEDs. Slap my hand.
But hey, it's my moolah.

But the best deal I found was the .22F 5V memory caps for only $.50
each, so I got twenty of those. I'll be on my way to completing that
Forever Flasher that I ranted about earlier. Five of those only cost
$2.50, which was less than the 1 farad for almost $3 at Mouser - even
more at Digi-Key. )

(Gee, at that price, I hope they're not used! They didn't say..)

--
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[Lewin A.R.W. Edwards]

For a specific application I'm looking for a transparent keyboard, ie a
keyboard made with keys that let see the underlying surface at least on a

You can of course buy membrane keyboard which are see-through, but I
would describe them as "translucent" rather than transparent.

Have you considered using a resistive touch screen? These are
available in almost any size you can imagine. You could have an
additional silkscreened clear plastic sheet under the tablet, with key
legends. I'm assuming you require no tactile response whatsoever

 

[Robert Lacoste]

Thanks, I had also in mind to use a touch screen, but my dear customer would
prefer something which has the same "feeling" than a standard keyboard (for
easy typying)... but a transparent one in order to see something under the
keyboard ... So I need more than a translucent one... Ideally I would like
to find "drilled" keyboard keys...

Robert

"Lewin A.R.W. Edwards" <larwe@larwe.com> a écrit dans le message de
news:608b6569.0309031338.1cd174f0@posting.google.com...

For a specific application I'm looking for a transparent keyboard, ie a
keyboard made with keys that let see the underlying surface at least on
a

You can of course buy membrane keyboard which are see-through, but I
would describe them as "translucent" rather than transparent.

Have you considered using a resistive touch screen? These are
available in almost any size you can imagine. You could have an
additional silkscreened clear plastic sheet under the tablet, with key
legends. I'm assuming you require no tactile response whatsoever

 

[Lewin A.R.W. Edwards]

Hi Robert,

prefer something which has the same "feeling" than a standard keyboard (for
easy typying)... but a transparent one in order to see something under the
keyboard ... So I need more than a translucent one... Ideally I would like
to find "drilled" keyboard keys...

I doubt you're going to find this item. I can point you at a keyboard
with translucent keys (from Apple iBook):
<http://www.pbparts.com/store/agora.cgi?product=_in&keywords=_cs>

(the photographs aren't very good; but the keys are clear). The
problem is that all PC-type keyboards will have a metal backplate (for
strength) and springs. Maybe you could adapt it.

Or perhaps you could project the image of what you want to see on top
of the keyboard

 

[JW]

On Thu, 4 Sep 2003 08:56:56 +0200 "Robert Lacoste" <rlacoste@alciom.com>
wrote in Message id: <3f56e229$0$20942$7a628cd7@news.club-internet.fr>:

Thanks, I had also in mind to use a touch screen, but my dear customer would
prefer something which has the same "feeling" than a standard keyboard (for
easy typying)... but a transparent one in order to see something under the
keyboard ... So I need more than a translucent one... Ideally I would like
to find "drilled" keyboard keys...

Robert

Howzabout this?:
http://www.slcentral.com/reviews/hardware/periph/coolgreen/fold2000/

 

[Robert Lacoste]

Or perhaps you could project the image of what you want to see on top
of the keyboard

May be not a bad idea... Many thanks for your input ;+)

 

[Walter Harley]

"William P.N. Smith" <wpns@compusmiths.com> wrote in message
news:356flvk2i748evnu4d6f28k27e0ig6b3vb@4ax.com...

Is there a chart somewhere of Alkaline battery capacities?

Most of the major battery manufacturers have data sheets on their web sites.
Go to, e.g., http://www.duracell.com.

 

[Gary Reichlinger]

On Thu, 04 Sep 2003 15:56:14 -0400, William P.N. Smith
<wpns@compusmiths.com> wrote:

Is there a chart somewhere of Alkaline battery capacities? oogle
pointed me at some hints that a D cell might have 14.25AH, which is
pretty impressive!

As indicated in other posts, the battery manufacturers have such
design information on their web sites. My favorite is
www.rayovac.com.