Mosquito Sound

[Jim Adney]

On Sun, 01 Aug 2004 12:42:46 GMT Daniel Rudy
<i0n1v2a3l4i5d6d7c8r9u0d1y2e3m4a5i6l7@n0o1p2a3c4b5e6l7l8s9p0a1m2.3n4e5t6>
wrote:

2. Wind a couple of turns of the main feed wire onto a torridal core
form. The torrid has a gap cut into it. Inside that gap is a hall
effect device that is epoxied into place. This inherently provides the
galvanic isolation that is required. After signal conditioning, the
analog voltage can be sent directly to a ADC input on the controller.

These are available as a commercial product from a Swiss company
called LEM. They make a good product line.

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

 

[Ed Price]

"Thomas P. Gootee" <tomg@fullnet.com> wrote in message
news:11915d6.0408011202.5096cf5b@posting.google.com...

Service Manuals, in PDF format:

There are lots of SERVICE MANUALS, for electronic test equipment, and
comms radios, etc etc, in PDF format, available at:

-----------------------------------------

http://www.

-----------------------------------------

There are hundreds of FULL SERVICE MANUALS

At $5 to $15 each, right Tom?

A frugal person might try this first:

https://www.logsa.army.mil/etms/find_etm.cfm

or

http://bama.sbc.edu/



Ed
WB6WSN

 

[Ed Price]

"Gary Reichlinger" <reichln@navix.net> wrote in message
news:k5dqg0derkjfltqndiqoloepj8m1hib6iu@4ax.com...

On Sun, 01 Aug 2004 17:34:44 GMT, Daniel Rudy
i0n1v2a3l4i5d6d7c8r9u0d1y2e3m4a5i6l7@n0o1p2a3c4b5e6l7l8s9p0a1m2.3n4e5t6
wrote:

And somewhere around the time of 08/01/2004 08:04, the world stopped and
listened as Gary Reichlinger contributed the following to humanity:

It ought to be embarrassing for a poster to ask a serious question, have it
seriously answered, and then reply with an automatic tag file that's
sarcastic and demeaning.

But I suppose Mr. Rudy is either too dumb to recognize his automated insult,
or too sophomoric to care.


Ed
wb6wsn

 

[Ed Price]

"Thomas P. Gootee" <tomg@fullnet.com> wrote in message
news:11915d6.0408020654.66e49acd@posting.google.com...

"Ed Price" <edprice@cox.net> wrote in message
news:<NjkPc.28758$mg6.15754@fed1read02>...
"Thomas P. Gootee" <tomg@fullnet.com> wrote in message
news:11915d6.0408011202.5096cf5b@posting.google.com...
Service Manuals, in PDF format:

There are lots of SERVICE MANUALS, for electronic test equipment, and
comms radios, etc etc, in PDF format, available at:

-----------------------------------------

unsnipped:

SNIPPED AGAIN

http://www.

There are hundreds of FULL SERVICE MANUALS


At $5 to $15 each, right Tom?

A frugal person might try this first:

https://www.logsa.army.mil/etms/find_etm.cfm

or

http://bama.sbc.edu/


Ed
WB6WSN

---------------------

Ed,

Actually, they range from $3 to $38, usually with shipping and
handling additional (although the higher-priced manuals are mostly the
ones that I sell for someone else, who works hard to create them).

Sure! LOGSA and BAMA are well known by those in the sci.electronics
groups, although I doubt that many others can mine LOGSA as thoroughly
as I have. I spent a huge amount of time and effort, and money,

Umm how did you spend money at LOGSA or BAMA?

developing and applying technicques for finding obscure manuals there,
and identifying the commercial model designations of the equipment
that they cover.

You needn't worry, though, Ed. Your "frugal types" are usually
hobbyists or students. For them, I have often just GIVEN away the
URLs for manuals (including many of the "unfindable" ones that I
worked so hard for), not to mention at least many hundreds of hours of
free help, advice, and technical consulting. [Of course,
unfortunately, I'll probably have to suspend those policies, for a
while, now that I've had to state them publicly.]

So being a nice guy is now on indefinite hold? And just when I had written
your address on my wall. Darn!

Nevertheless, I still deeply resent the "socialist types" who seem to
think that everything should be "free", or at cost. If that were the
case, I couldn't BE here, and wouldn't HAVE the MEANS to provide the
"newbie help" and the hobbyist/student deals, etc. (Moral: "Be careful
what you wish for. You just might get it.")

Thanks for the reply.

Sorry, but I snipped the balance of your long-winded, multi-market ad once
you started topics from astronomy to vegetables.
You sure do like to advertise!

I don't think it's "socialist" to point out that USA citizens have already
paid for all those LOGSA manuals, and that the information ought to be
freely available to them what has already paid the bill. It's certainly
capitalistic to carve out a market niche, packaging and selling what is
already publicly available. We assume your customers are paying for
convenience (yes, the LOGSA site is rather, uhh, facelessly bureaucratic
<g&gt.

OTOH, don't cry when someone points out that the air is free, and tells
people how to breathe deeply on their own.

BAMA's quite a different thing. The information, and the venue, are all
provided as gifts. Assuming that a newbie only has to acquire the talent to
use FTP, there's not much of a barrier to getting the help yourself. I have
a hard time accepting anyone repackaging those gifts as a saleable product.

Ed
wb6wsn
"nothing for sale today"

 

[Robert Baer]

Daniel Rudy wrote:

Hello Everyone!

I've ran into a situation where I need to sense a very large flow of
current (100A) at 24VDC or so. This is for a motor supply feed. The
problem that I'm running into is isolation because there is a
microcontroller that is part of the control circuit that electrically
needs to stay away from this line as its powered from a different
source. So far, there are two ways that I'm aware of to do this:

1. Use a very low value resistor (I would need a few in parallel),
sense and amplify the voltage across that. Then feed that into a
voltage to frequency converter so it can be sent across an opto-isolator
and then on to a timer on the microcontroller.

2. Wind a couple of turns of the main feed wire onto a torridal core
form. The torrid has a gap cut into it. Inside that gap is a hall
effect device that is epoxied into place. This inherently provides the
galvanic isolation that is required. After signal conditioning, the
analog voltage can be sent directly to a ADC input on the controller.

I would prefer to use #2 as that would be easier to implement, and it
seems to have a lower parts count. Accuracy in the area of 1 amp
resolution or better, if possible, would be good. Any advise, links,
etc. is appreciated. Thanks.

--
Daniel Rudy

Email address has been encoded to reduce spam.
Remove all numbers, then remove invalid, email, no, and spam to reply.

Since you state DC current, and high voltage isolation, ther are two
solution types:
1) Hall effect transducer. These can do the job, but one cannot get 1%
accuracy, linearity or temperature insensitivity that you seem to
demand.
But if you are willing to put up with about 12% nonlinearity with
isolationof 5nA at 2000V, look at the Zetex ZMC20 (need to modify
magnetic coupling to allow 100A sensing).
2) Current transformer (fluxgate) as made by LEM. Expensive, but gives
wideband and precision response. Perhaps you could "roll your own".

 

[Gary Reichlinger]

Here is a current (excuse the pun) article on the subject:

http://www.reed-electronics.com/ecnmag/article/CA433401?nid=2274&rid=40817004

 

[Winfield Hill]

Gary Reichlinger wrote...

Here is a current (excuse the pun) article on the subject:

http://www.reed-electronics.com/ecnmag/article/CA433401?nid=2274&rid=40817004

Except the repated INA183 reference has to be wrong. Hmm, perhaps
it's an INA138 instead, but then the common-mode specs are wrong.

--
Thanks,
- Win

(email: use hill_at_rowland-dot-org for now)

 

[JW]

On 4 Aug 2004 11:45:52 -0700 usenet@jaseroberts.net (Jase Roberts) wrote
in Message id: <af54826d.0408041045.6dc17cbc@posting.google.com>:

I'm looking for a basic power meter that would allow me to measure how
much electricity my major home appliances use. I've already put
together a little adaptor that lets me insert my multimeter into the
circuit to do instantaneous readings on lower wattage things (e.g. my
computer). However, this will only work up to 10A, and the
instantaneous readings are really only useful for estimating power
consumption of things that have fairly constant draw.

What I'm hoping to find is something like a miniature version of the
electric meter you find outside your house. It would have a cord to
plug into the wall socket (both 110V & 220V would be ideal), and a
socket on the unit to plug in the appliance. You'd then leave it in
place for a month or so and see what the cumulative usage has been.
This would be ideal for checking consumption on appliances like a
refrigerator, microwave, washer, etc that have intermittant spikes of
high usage followed by periods of no draw.

Is it possible to buy a commercial version of a meter like this? If
not, any suggestions of what components one could use to build one?
What about buying a used household meter (big dials and all) and
wiring that up?

How about:
http://www.gaiam.com/retail/product.asp?product_id=25819

 

[JW]

On 4 Aug 2004 11:45:52 -0700 usenet@jaseroberts.net (Jase Roberts) wrote
in Message id: <af54826d.0408041045.6dc17cbc@posting.google.com>:

I'm looking for a basic power meter that would allow me to measure how
much electricity my major home appliances use. I've already put
together a little adaptor that lets me insert my multimeter into the
circuit to do instantaneous readings on lower wattage things (e.g. my
computer). However, this will only work up to 10A, and the
instantaneous readings are really only useful for estimating power
consumption of things that have fairly constant draw.

Or even
http://www.gaiam.com/retail/product.asp?catalog%5Fname=gai&category%5Fname=l3%5FMetersAdvanced&product%5Fid=25818

It's cheaper.

 

[Roger Gt]

"Jase Roberts" <usenet@jaseroberts.net> wrote in message
news:af54826d.0408041045.6dc17cbc@posting.google.com...
: I'm looking for a basic power meter that would allow me to
measure how
: much electricity my major home appliances use.

<snip>

: Is it possible to buy a commercial version of a meter like this?
If
: not, any suggestions of what components one could use to build
one?
: What about buying a used household meter (big dials and all) and
: wiring that up? Thanks, Jase


Not with such Big dials. But try

http://shop.store.yahoo.com/supermediastore/kilwateldet1.html

$25 is a good price, I have two I use around the house for
auditing, they work very well!

Roger Gt

 

[normanstrong]

"JW" <none@dev.nul> wrote in message
news:78b4h0pfaopf1gh40hbuo6r8q7keba3m87@4ax.com...

On 4 Aug 2004 11:45:52 -0700 usenet@jaseroberts.net (Jase Roberts)
wrote
in Message id: <af54826d.0408041045.6dc17cbc@posting.google.com>:

I'm looking for a basic power meter that would allow me to measure
how
much electricity my major home appliances use. I've already put
together a little adaptor that lets me insert my multimeter into
the
circuit to do instantaneous readings on lower wattage things (e.g.
my
computer). However, this will only work up to 10A, and the
instantaneous readings are really only useful for estimating power
consumption of things that have fairly constant draw.

Or even

http://www.gaiam.com/retail/product.asp?catalog%5Fname=gai&category%5Fname=l3%5FMetersAdvanced&product%5Fid=25818

It's cheaper.

I have one of these units. It has a serious flaw. If the power fails
for even a second, it loses its memory, and your reading of
accumulated watthours is gone. There should be a battery in it to
maintain its memory.

Norm Strong

 

[Fred McKenzie]

<< I replace the ballast of the fluorescent lamp with capacitor the
tube is 20watt '60cm worked at 220 volt I replace it's ballast with a
capacitor 10uf 400 volt non polar the tube give a light but the light
is flash the frequencey is 50 hz is there is any modification to
overcome this problem ? >>

Yar-

This is not a new idea. I've seen capacitors used as ballasts with battery
powered lamps, where AC was generated at a high frequency to drive the
fluorescent lamp.

As far as your 50 Hz, isn't that your local AC power frequency? As long as you
use AC with a flourescent lamp, it will flash, but probably at twice the power
frequency. The lamp is not polarized, so it ignites on both positive and
negative voltage peaks.

To get around that, you would need to rectify the AC power, use the D.C. to
drive an oscillator at a higher frequency, and drive the lamp (using a new
ballast) with that instead. Of course it will still be flashing, but at a
higher frequency.

It might be possible to drive a flourescent lamp using D.C., but you would need
a resistor to limit current, which would get hot and waste power.

73, Fred, K4DII

 

[mike]

Scott Gibson wrote:

I have some probes I'm looking to sell but I can't find a reasonable
value to sell them at. And I don't really know where to post them
forsale. I don't expect the retail value, I just want to know what a
fair price would be.

Here is what I have:
- Tek P6022 Current Probe (120Mhz) unopened with manual, and all the
extras (clips, termination, etc). ($1050 US new retail)
- two Tek P6057 probes (100X, 1.4GHz, I still need to test them).
(~$200 Retail)

Thank you,

Scott

There's this website that's all the rage.
It's a great place for sellers to get insanely high prices for stuff.
WWW.EBAY.COM
Try it.
mike

--
Return address is VALID.
Wanted, 12.1" LCD for Gateway Solo 5300. Samsung LT121SU-121
Bunch of stuff For Sale and Wanted at the link below.
Compaq Aero floppy,ram,battery.
FT-212RH 2-meter 45W transceiver. 2-meter linear
Toshiba & Compaq LiIon Batteries, Test Equipment
30pS pulser, Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

 

[John Schuch]

Carl Banks wrote:

--<snip>--

So, can anyone point me to something that does what I need? More
generally, does this sound like a good strategy? I'm open to
suggestions.
--<snip>--

Do a web search on "RF modems". There are a lot of companies that make
fairly inexpensive units. You could use a cheaper PIC, and output RS-232
into an RF modem linked to your PC. As a bonus, your PC could also talk
to your PIC and do any kind of control you might need.

http://www.alltheweb.com/search?cat=web&cs=utf8&q=RF+modems&rys=0&_sb_lang=pref

John

 

[Joe Soap]

In response to what John Schuch <news@esdres.com> posted in
news:_64Rc.12012$cK.6891@newsread2.news.pas.earthlink.net:

Carl Banks wrote:

--<snip>--
So, can anyone point me to something that does what I need? More
generally, does this sound like a good strategy? I'm open to
suggestions.
--<snip>--

Do a web search on "RF modems". There are a lot of companies that make
fairly inexpensive units. You could use a cheaper PIC, and output
RS-232 into an RF modem linked to your PC. As a bonus, your PC could
also talk to your PIC and do any kind of control you might need.

http://www.alltheweb.com/search?cat=web&cs=utf8&q=RF+modems&rys=0&_sb_l
ang=pref

John

http://www.pacscom.com

--
Joe Soap.
JUNK is stuff that you keep for 20 years,
then throw away a week before you need it.

 

[Tim Auton]

imbosol@aerojockey.com (Carl Banks) wrote:
[snip]

It's the receiver I'm wondering about. I kind of expected this to be
a rather typical use for a transmitter (send telemetry to your
computer), so I kind of expected to see some receievers that I could
connect to a PC, say via a serial port, obviating the need to build
one myself. But I can't find any.

http://www.lprs.co.uk/main/easy-radio.php

Does exactly what it says on the tin.


Tim
--
Google is not the only search engine.

 

[Robert Baer]

Phil wrote:

Hello All,

A friend of mine just gave me a big power transformer that he
took out of an old Tektronix tube oscilloscope. He doesn't remember
the model of this scope but he says that it had a big air filter in
the back and had two leather handles on top. They probably where all
like that! I was wondering if someone knew the pinout and some details
about this tranny. The model number is 120037 and it has two blue
colored end bells

Thanks in advance,
Phil

Best way is to do the following:
1) Use an ohmmeter, and determine windings (eg: 3 ohms 1-2, 300 ohms
15-15, etc).
2) Use either a variac (set to 10 percent of full value) or a filament
transformer to drive one of the 3-5 ohm windings. Note that the "zero
ohm" (or close to that) windings are filament windings, and that the
high resistance windings are high voltage.
3) Measure the input AC voltage on the 3-5 ohm winding, and the AC
voltage on all of the other windings.
From those values, one can then easily determine the filament
windings, and usually the primary/primaries. One could use ratios here,
to determine ratings of all windings.
Usually, these transformers have two 120V windings (1-3 and 2-4 most
likely), which helps geratly.
When a given winding like those mentioned "stand out", then one can
appropiately connect the variac or filament transformer for
verification.

 

[mike]

Robert Baer wrote:

Phil wrote:

Hello All,

A friend of mine just gave me a big power transformer that he
took out of an old Tektronix tube oscilloscope. He doesn't remember
the model of this scope but he says that it had a big air filter in
the back and had two leather handles on top. They probably where all
like that! I was wondering if someone knew the pinout and some details
about this tranny. The model number is 120037 and it has two blue
colored end bells

Thanks in advance,
Phil


Best way is to do the following:
1) Use an ohmmeter, and determine windings (eg: 3 ohms 1-2, 300 ohms
15-15, etc).
2) Use either a variac (set to 10 percent of full value) or a filament
transformer to drive one of the 3-5 ohm windings. Note that the "zero
ohm" (or close to that) windings are filament windings, and that the
high resistance windings are high voltage.
3) Measure the input AC voltage on the 3-5 ohm winding, and the AC
voltage on all of the other windings.
From those values, one can then easily determine the filament
windings, and usually the primary/primaries. One could use ratios here,
to determine ratings of all windings.
Usually, these transformers have two 120V windings (1-3 and 2-4 most
likely), which helps geratly.
When a given winding like those mentioned "stand out", then one can
appropiately connect the variac or filament transformer for
verification.

Or you could go here

http://groups.yahoo.com/group/TekScopes/

and ask again.
mike

--
Return address is VALID.
Wanted, 12.1" LCD for Gateway Solo 5300. Samsung LT121SU-121
Bunch of stuff For Sale and Wanted at the link below.
Compaq Aero floppy,ram,battery.
FT-212RH 2-meter 45W transceiver. 2-meter linear
Toshiba & Compaq LiIon Batteries, Test Equipment
30pS pulser, Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

 

[ptaylor]

Dan Fraser wrote:

You expect the sales people at RS to know anything about the products. You
had may as well ask for the best wine to go with a Big Mac.

As for requiring a SS number, that is blatantly illegal. Or you can give a
fake one

666-66-6666

Wanna make something of it.

When paying by cash I say the name is.

C. Ash
1313 Mockingbird Lane
Hollywood CA 99666

Again, if they don't like it, they could stuff it.

However, at the local RS, here in Costa Mesa, they no longer ask for name or
address on cash purchases. I think they finally grasped that is the one
thing that really pissed people off about them.

If you need parts to build anything, forget RS.

www.mouser.com

www.digi-key.com

I usually reply simply with "Cash"..if the sales-driod doesn't catch
on,and ask's me for my first name.. "Cash"....by then they usually get
it,and ring me up without any further questions.

RadioShack is worthless now days.. Last time I went in there looking for
a simple digital IC (a NAND gate,I think..) I was directed to a rack
with 4-5 IC"s on it,what was left over..
I went to the drawers with the LED's and stuff 2 LED's in the store,and
they didn't have any in back.. (or were too lazy to look) most all the
drawers were empty,and I was told that they are "phasing out" component
sales.. That's all they were good for,and now even that is history..
I went to *4* stores one day looking for 1 single 100K pot...none of
them had any pots whatsoever,and the parts selection in the other 3
stores was also nearly non-existant.

RadioShack is Worthless.

 

[Robert Baer]

"Christopher A. Steele" wrote:

I'm looking to build my own Ultrasonic tank. But due to the nature of
the things I'd like to try cleaning (baseball hats, maybe some of my
dirtier LPs [vinyl records for those of you who are of the CD
generation]), I'm concerned with the VIOLENCE of the cavitation.

So I'm looking to construct a more gentle ultrasonic tank, if there
can be such a thing, and the physics allow.

IS THERE a relationship between the wattage of such a unit and the
violence of the cavitation; or between the amount of liquid acted on
by 'x' wattage and the resultant cavitation, or ... what?
HOW can I "tone things down" in the tank?

(For the record, The Swiss National Sound Archives selectively uses
ultrasonics to clean some of their records, but I've yet to get a
response from them on what they use and how they use it. I've also
seen units designed to clean contact lenses which would seem fairly
fragile. And I'm aware (barrrrrely) of Sameer Madanshetty's efforts to
use lower frequencies to ameliorate the violence of cavitation, but
have no idea of the frequencies used, and fear the science is WAYYYY
beyond my humble abilities anyway.)
Please Note: I'm not a scientist. Nor do I have a degree in, or
significant knowledge of, physics. I'm just reading and learning bit
by bit: So, layman's terminology would be Greatly appreciated in any
response anyone cares to take the time to make.

You all have a wunderbar day. From San Diego, California, I am

Christopher A. Steele
Son of Col. M.J. Steele, USASA/AGC, Fts: Devens, Rucker, Lawton,
OATerm, +
casteele95thbgheavy

Seems the physics is as follows..
Sound travels thru a medium as a sequence of compressed and
rarification of that medium; most especially in the case of a liquid or
a gas.
So, it seems the energy needs to be large enough to break the
inter-molecular bonding of (in this case) the fluid.
I cannot say that this is frequency dependent or not, but would hazard
a guess that, to some point, the higher the frequency, the lower the
"critical point" energy would be for cavitation.
So, the solution would seem to use a liquid with low inter-molecular
bonding.
One clue to that would seem to be surface tension; so try alcohol, and
if there is a surfactant ("soap") that is good for alcohol, add that.
With this combination, i think you could lower the power requirements
(at same frequency, if dependent on frequency) by at least a factor of
two or more (maybe four??).