magnetic field

[Michael Black]

"PeteS" (ps@fleetwoodmobile.com) writes:

A great number of newer devices come in 'FlipChip' packages, where the
'lid' of the chip is immediately above the die - this is done for
effective thermal transfer to heat sinks - these are easy to dissect -
pop the heat sink off for many of them, and the die os there for you to
see.

Cheers

PeteS

And I'm sure many have learned this the hard way.

Michael

 

[exxos]

"twags6" <twags6@hotmail.com> wrote in message
news:1114104085.980995.74540@o13g2000cwo.googlegroups.com...

It would mainly be for testing various equipment such as dc motors, car
amps, etc. I was looking for something with decent regulation that i
could possibly build. I've seen a few designs, but i'm not sure what
the best would be.

heres a few i found:
http://www.mitedu.freeserve.co.uk/Circuits/Power/1230psu.htm
http://ourworld.compuserve.com/homepages/Bill_Bowden/page12.htm#5reg.gif

the regulator is easy, any switchmode chip powering a external fet will do
the job, the hardest part is finding a transformer which will kick out
50amps.....

Chris

 

[John Fields]

On 21 Apr 2005 11:15:32 -0700, cswanson2@austin.rr.com wrote:

Was hoping a sci.electronics person might be able to help. I need a
find/buy/make a 24V power suuply that powers a 24V .55 amp pool valve
actuator switch. The system is is used on is 24V based and puts out .55
amps, so anything in that range should work.

I'm not terrribly familiar with power supplies, so any pointers would
help.

---
90-246VAC in, 24VDC +/- 1%, 0.63A out, $16.36 qty 1

CUI P/N DMS240063-P5P-SZ

Digi-Key P/N T376-P5P-ND


--
John Fields
Professional Circuit Designer

 

[Ariane]

Hi, hier sind meine geilen Bilder!
My nude Pics!!!
http://www.geile-tipps.info/go/

--
Posted by News Bulk Poster
Unregistered version

 

[Dennis]

Dan Piponi wrote:

That sounds exactly like what I must be doing wrong. But how do I set
to two line mode? I can't see anything about 2 line mode in the hd44780
docs I can find on the web.

Look for the Function Set command 001DNFxx

D - interface data length 1 = 8 bit, 0 = 4 bit
N - number of lines 1 = 2 lines, 0 = 1 line
F - font 1 = 5x10, 0 = 5x8
xx - don't care

Default is 00100000

you want 00110000 (0x30)

 

[John]

On 21 Apr 2005 00:04:33 -0700, "twags6" <twags6@hotmail.com> wrote:

Is there any way to make a dc power supply capable of 50+ amps at
12-13.8 vdc? Basically, I'm looking for something to simulate the
power from a car without the whole battery and charger setup. Parts
express sells a nice rackmount one, but I'd rather not part with $190.

TIA

Trevor

A sealed lead-acid or lead-calcium battery and an appropriate charger
will provide the power you want for much less than an equivalent DC
supply.

A 25AH sealed lead-calcium is available in the US for $40 including
UPS Ground shipping: http://hamcall.net/liberty1000.html

You need a charger large enough to keep the battery from discharging
more than halfway when under load. If the load is intemittent
(typical of most testing) then a trickle charger may be adequate.

I used a standard automotive battery and a 10amp DC supply for testing
mobile radios that drew appreciably more than 10 amps when
transmitting - the battery provided the additional power needed. A
sealed battery is a MUCH better solution - and the one listed above is
price competitive with a typical automotive battery.

John

 

[blazeinferno]

Hi,

The output is 65W. Does the charger specify how many watts on the
input side or maybe how much current it consumes on 120V?
If it does specify the current then: Power (Watts=Volts *Amps) and that
should tell you the minimum power your transformer should be able to handle.
If nothing is specified for the input side, then I would estimate the
efficiency of the charger to be at worst 75%. With this approximation, the
input power should roughly be about 65W/0.75=87W. A transformer between 85W
and 100W should be fine. The power for 120V or 240V will still be the same.
The fundamental difference is that current is halved at 240V.

Hope this helps


Ciao

Fern



"EF" <electronicfur@yahoo.co.uk> wrote in message
news:37e4eaf1.0504111419.3c1dbc1f@posting.google.com...

Hi I'd appreciate some help.

I have a NiMh battery charger which has AC input of 100~120VAC
50~60HZ, 1.2A.

It outputs at 36VDC, 1.8A.

How many Watt transformer do I need to use this charger in the UK
where we have 240V? The output of the charger itseff is only 65W, but
the input is more, but I'm not sure how to take the phase into
account.

Cheers,
EF

 

[blazeinferno]

Hi Patrick,

You would need:

I(ma)3.1W/6)*1000=517ma minimum adaptor.

Don't forget to verify the polarity before
connecting the adaptor.

Hope this helps

Fern

"Annie" <afritz@aol.com> wrote in message
news:d3so8q$hfr$1@reader01.singnet.com.sg...

Hi, I just bought a portable handheld tv, the Casio TV-970, and want to
purchase a universal adaptor for it.
The universal adaptors I've seen have different ratings, from 350mA, to
over
1000mA.
The specifications on the user guide says that it runs on 6 volts, and the
power consumption is approximately 3.1W.

How much mA do I need?

Regards,
Patrick

 

[CWatters]

"Doctor Dave" <remzak@excite.com> wrote in message
news:1114083731.105227.185790@z14g2000cwz.googlegroups.com...

Hi,

I'm doing some research on materials forming and would like to
replicate the surface of a CPU die on the nm level. Does anyone have
any experience on removing the packaging on modern CPUs to reveal the
die?

If you want to expose the die in a particular chip there are ways of
disolving the plastic so that the die is left intact. I saw it done about 15
years ago. It's expensive to have it done but try:..

http://siliconcert.com/reliability_news/r_news_fourteen.htm

If you don't care about which chip it is find one in a ceramic LCC package
and unsolder the lid eg..

http://www.amkor.com/Products/all_products/LLCC.cfm

 

[Watson A.Name - \"Watt Su]

"twags6" <twags6@hotmail.com> wrote in message
news:1114067073.072994.268340@f14g2000cwb.googlegroups.com...

Is there any way to make a dc power supply capable of 50+ amps at
12-13.8 vdc? Basically, I'm looking for something to simulate the
power from a car without the whole battery and charger setup. Parts
express sells a nice rackmount one, but I'd rather not part with $190.

TIA
Trevor

You might be able to find better deals on Astron or other similar power
supplies. This company sells a 45A PS for over $200. You may be able
to get a used one on Ebay for a lot less.
http://www.skywavzelectronics.com/powersupplies.htm

 

[Robert Scott]

On 22 Apr 2005 07:01:21 -0700, dhaevhid@hotmail.com (dhaevhid) wrote:

hi! im a total newbie on the field of assembly programming and the
microcontrollers stuff and im trying to build a digital guitar tuner
more like the ones which automatically detects the string being tuned
and has an LCD "analog needle-display"... any kind of help would be
greatly appreciated.. sample codes, ideas, references, anything would
be great..

Are you doing this just for practice? Why else would you want to
re-invent something that is available in music stores at low prices?

-Robert Scott
Ypsilanti, Michigan

 

[Rich Grise]

On Thu, 21 Apr 2005 03:32:11 +0000, ehsjr wrote:

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

I'm just curious as to why you'd want to use a toroid. The whole idea
of a toroid is to increase the magnetic field containment, so you get
better inductance. Then you go winding it bifilar, to _get_rid_ of the
inductance! This doesn't make sense.

First, it is not bifilar. Picture a center tapped coil wound single
layer on a toroid. It is that, except that the second half is wound in
the opposite direction.

And it makes sense. I'll try a diagram.

+------+-----------------+
| | |
| Mosfet |
___ | B
___ +------|<----+ A
| ( | T
| ( L1 | T
| ( | E
+------+ | R
) | Y
) L2 | |
) | |
-----------+------------+----+

L2 isolates the bottom of L1 from the negative rail on the discharge
part of the cycle. On the charge part, the Xl's cancel out, leaving only
the winding R in the charge path. That allows reduction of the charge
time.

Yabbut, that's a reset winding. We were talking about noninductive
wirewound resistors.

Cheers!
Rich

 

[ehsjr]

Rich Grise wrote:

On Thu, 21 Apr 2005 03:32:11 +0000, ehsjr wrote:

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


I'm just curious as to why you'd want to use a toroid. The whole idea
of a toroid is to increase the magnetic field containment, so you get
better inductance. Then you go winding it bifilar, to _get_rid_ of the
inductance! This doesn't make sense.


First, it is not bifilar. Picture a center tapped coil wound single
layer on a toroid. It is that, except that the second half is wound in
the opposite direction.

And it makes sense. I'll try a diagram.

+------+-----------------+
| | |
| Mosfet |
___ | B
___ +------|<----+ A
| ( | T
| ( L1 | T
| ( | E
+------+ | R
) | Y
) L2 | |
) | |
-----------+------------+----+

L2 isolates the bottom of L1 from the negative rail on the discharge
part of the cycle. On the charge part, the Xl's cancel out, leaving only
the winding R in the charge path. That allows reduction of the charge
time.


Yabbut, that's a reset winding. We were talking about noninductive
wirewound resistors.

Cheers!
Rich

The point I was making was about *windings*, the direction

they go, the fact that the inductances cancel out (verifying
what you were told from my own experience with coils wound
on toroids), and the fact that they are not bifilar.
I didn't think it necessary to state that the thing wound on
a toroid wasn't intended to be a resistor, figuring that is
obvious. But perhaps not....
Ed

 

[Watson A.Name - \"Watt Su]

"ehsjr" <ehsjr@bellatlantic.net> wrote in message
news:cMiae.477$Yc.187@trnddc06...

Rich Grise wrote:
On Thu, 21 Apr 2005 03:32:11 +0000, ehsjr wrote:

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

I'm just curious as to why you'd want to use a toroid. The whole
idea
of a toroid is to increase the magnetic field containment, so you
get
better inductance. Then you go winding it bifilar, to _get_rid_ of
the
inductance! This doesn't make sense.

First, it is not bifilar. Picture a center tapped coil wound single
layer on a toroid. It is that, except that the second half is wound
in
the opposite direction.

And it makes sense. I'll try a diagram.

+------+-----------------+
| | |
| Mosfet |
___ | B
___ +------|<----+ A
| ( | T
| ( L1 | T
| ( | E
+------+ | R
) | Y
) L2 | |
) | |
-----------+------------+----+

L2 isolates the bottom of L1 from the negative rail on the discharge
part of the cycle. On the charge part, the Xl's cancel out, leaving
only
the winding R in the charge path. That allows reduction of the
charge
time.

Yabbut, that's a reset winding. We were talking about noninductive
wirewound resistors.

Cheers!
Rich

The point I was making was about *windings*, the direction
they go, the fact that the inductances cancel out (verifying
what you were told from my own experience with coils wound
on toroids), and the fact that they are not bifilar.
I didn't think it necessary to state that the thing wound on
a toroid wasn't intended to be a resistor, figuring that is
obvious. But perhaps not....
Ed

I can only speak for others, not myself. er, whatever...

Here's a copy of your original post (between the << and >&gt:

<<

Bifilar means to me that the wires stay parallel throughout:

Loop
^
\\ \\ \\ \\ \\_
\_ Leads

But the one I had in mind was more like this:
Loop
^
Lead _/ / / / \ \ \ \_ Lead

I don't know what it's called.

Cheers!
Rich

That's it, exactly. Someone called it "contra-wound" -

but I don't know if that is the proper term. On the toroids
I wind that way, the first half occupies about 40% of
the diameter and the last half occupies another 40%.
Ed
But earlier, this whole thread was all about cancelling inductance so I
assumed that the point of doing either of these was to cancel out the
inductance.

In my case, I was thinking that the first example, \\ \\ \\.. is the way
they were telling me to wind the turns on the resistor with 2 conductors
paralleled in each turn. Of course this is to cancel out inductance.

Then you talked about contra-wound on a toroid. I assumed this was to
cancel out inductance as was being done previously. I did make a
mistake about yours being bifilar. Sorry.

But to continue, I would like to see the complete circuit with the
MOSFET you drew above. Might make a whole lot more sense.

 

[Gizmofiddler]

Would a standard 24V doorbell transformer supply enough power?
Is that AC or DC?

<cswanson2@austin.rr.com> wrote in message
news:1114107332.616215.192940@o13g2000cwo.googlegroups.com...

Was hoping a sci.electronics person might be able to help. I need a
find/buy/make a 24V power suuply that powers a 24V .55 amp pool valve
actuator switch. The system is is used on is 24V based and puts out .55
amps, so anything in that range should work.

I'm not terrribly familiar with power supplies, so any pointers would
help.

Thanks,

Carl
cswanson2@austin.rr.com

 

[John Woodgate]

I read in sci.electronics.design that dhaevhid <dhaevhid@hotmail.com>
wrote (in <23be6f4c.0504230011.4415c399@posting.google.com&gt about
'DIGITAL GUITAR AUTO-TUNER PROJECT', on Sat, 23 Apr 2005:

so i finally resolved into seeking the help from the newsgroups and
forums. i know lots of you guys are not willing to help me because this
is really my own assignment.

Generally, that's not true. Many will HELP; we won't provide model
answers for homework projects.

well, im just tryin my luck if there's anyone out there willing to
share his expertise on this field...

Did you see four positive replies, offering help? I can't help in this
case; it's out of my field. I would only say that if you don't need to
use an LCD display, don't An LM3914 and ten LEDs is a much simpler
solution.
--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Rich The Newsgroup Wacko]

On Sat, 23 Apr 2005 01:11:51 -0700, dhaevhid wrote:

i wont try to be a freakin liar here guys, i will tell you my real
situation.

its actually a qualifying sample project for my first job. actually, i was
just tasked to study the assembly programming and hardware design and be
able to produce a working model for me to qualify for the job.

Well, hell, I'll do the whole thing for you - just sign over your
f**king paycheck.


Asshole.

im tryin to do it all by myself but its taking me so long to understand
the concepts... im reading tutorials and references i downloaded from the
internet but most of the times i found myself confused and i dont have
anyone to ask my questions. the senior engineers here are not that
helpful. they will just say " research in the internet, it might be
there"...

so i finally resolved into seeking the help from the newsgroups and
forums.
i know lots of you guys are not willing to help me because this is really
my own assignment.

well, im just tryin my luck if there's anyone out there willing to share
his expertise on this field...

thanks guys!
more power.

==dhaevhid==



"kunil" <kunilkuda@gmail.com> wrote in message
news:<1114183363.535733.29330@g14g2000cwa.googlegroups.com>...
Well, reinventing the wheel is always fun..

I'm also guitar player and I would like to build my own guitar
tuner..just for fun

I already have the schematic and the firmware in my head. The problem is
I dont have time to do it.

If you like, we can work together. I'll give you direction, some
tutorial&explanation for free..but in one condition : the hardware's
schematic/firmware must be released as GNU GPL licence.

We can use this usenet (or if necessary we build our own mailing list in
yahoogroups) to share information.

Anybody have interest to join in ?

-kunil
Bandung, Indonesia

--
Cheers!
Rich
------
"Why I am an atheist: 1. Atheists do not believe in higher powers. 2. God is the highest power. 3. Therefore, God must be an atheist. 4. We should all strive to be like God. 5. We should all be atheists."

 

[Ronald H. Nicholson Jr.]

In article <23be6f4c.0504220601.6f4a75ef@posting.google.com>,
dhaevhid <dhaevhid@hotmail.com> wrote:

hi! im a total newbie on the field of assembly programming and the
microcontrollers stuff and im trying to build a digital guitar tuner
more like the ones which automatically detects the string being tuned
and has an LCD "analog needle-display"...

What kind of guitar? What kind of sound transducer? What sample rate?
Signal to noise ratio? How powerful a microcontroller (MIPS, MFLOPs or
MACs per sample)? To what tuning accuracy? With what response time?

Depending on your answers, you might need to examine different solution
methods... anything from counting samples between zero crossings to
interpolated complex cepstrums.


IMHO. YMMV.
--
Ron Nicholson rhn AT nicholson DOT com http://www.nicholson.com/rhn/
#include <canonical.disclaimer> // only my own opinions, etc.

 

[ehsjr]

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

"ehsjr" <ehsjr@bellatlantic.net> wrote in message
news:cMiae.477$Yc.187@trnddc06...

Rich Grise wrote:

On Thu, 21 Apr 2005 03:32:11 +0000, ehsjr wrote:


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

I'm just curious as to why you'd want to use a toroid. The whole

idea

of a toroid is to increase the magnetic field containment, so you

get

better inductance. Then you go winding it bifilar, to _get_rid_ of

the

inductance! This doesn't make sense.

First, it is not bifilar. Picture a center tapped coil wound single
layer on a toroid. It is that, except that the second half is wound

in

the opposite direction.

And it makes sense. I'll try a diagram.

+------+-----------------+
| | |
| Mosfet |
___ | B
___ +------|<----+ A
| ( | T
| ( L1 | T
| ( | E
+------+ | R
) | Y
) L2 | |
) | |
-----------+------------+----+

L2 isolates the bottom of L1 from the negative rail on the discharge
part of the cycle. On the charge part, the Xl's cancel out, leaving

only

the winding R in the charge path. That allows reduction of the

charge

time.

Yabbut, that's a reset winding. We were talking about noninductive
wirewound resistors.

Cheers!
Rich


The point I was making was about *windings*, the direction
they go, the fact that the inductances cancel out (verifying
what you were told from my own experience with coils wound
on toroids), and the fact that they are not bifilar.
I didn't think it necessary to state that the thing wound on
a toroid wasn't intended to be a resistor, figuring that is
obvious. But perhaps not....
Ed


I can only speak for others, not myself. er, whatever...

Here's a copy of your original post (between the << and >&gt:

No! The post you quoted (below) was from Rich, not me.
My reply to it begins with the words "That's it , exactly."

Bifilar means to me that the wires stay parallel throughout:

Loop
^
\\ \\ \\ \\ \\_
\_ Leads

But the one I had in mind was more like this:
Loop
^
Lead _/ / / / \ \ \ \_ Lead

I don't know what it's called.

Cheers!
Rich


That's it, exactly. Someone called it "contra-wound" -
but I don't know if that is the proper term. On the toroids
I wind that way, the first half occupies about 40% of
the diameter and the last half occupies another 40%.
Ed


But earlier, this whole thread was all about cancelling inductance so I
assumed that the point of doing either of these was to cancel out the
inductance.

In my case, I was thinking that the first example, \\ \\ \\.. is the way
they were telling me to wind the turns on the resistor with 2 conductors
paralleled in each turn. Of course this is to cancel out inductance.

Then you talked about contra-wound on a toroid. I assumed this was to
cancel out inductance as was being done previously. I did make a
mistake about yours being bifilar. Sorry.

But to continue, I would like to see the complete circuit with the
MOSFET you drew above. Might make a whole lot more sense.


You're seeing most of it. Add a 555 circuit to the gate

of the mosfet and you have it. See
http://www.homepower.com/files/desulfator.pdf

I can post pictures of a toroid wound that
way, if it would make things clearer.
Ed

 

[Bob Monsen]

dhaevhid wrote:

i wont try to be a freakin liar here guys, i will tell you my real
situation.

its actually a qualifying sample project for my first job. actually, i
was just tasked to study the assembly programming and hardware design
and be able to produce a working model for me to qualify for the job.

im tryin to do it all by myself but its taking me so long to
understand the concepts... im reading tutorials and references i
downloaded from the internet but most of the times i found myself
confused and i dont have anyone to ask my questions. the senior
engineers here are not that helpful. they will just say " research in
the internet, it might be there"...

so i finally resolved into seeking the help from the newsgroups and
forums.
i know lots of you guys are not willing to help me because this is
really my own assignment.

well, im just tryin my luck if there's anyone out there willing to
share his expertise on this field...

thanks guys!
more power.

Here are some resources:

CircuitCellar... there is a guitar tuner article that uses a
microcontroller. The article describes the entire thing, and gives you a
schematic and a listing of the assembler code.

LCD, it's a snap, given the reams of free code available to drive those
little 16 character one line displays. HD44780 LCDs are cheap. You can
drive them with 11 datalines in 8 bit mode, and 7 in 4 bit mode, and 6
if you just hardwire the write pin high.

Here is a reference: http://ouwehand.net/~peter/lcd/lcd.shtml

They are kind of painful to program, so use a microcontroller with an
on-chip debugger.

I've had some trouble using that CircuitCellar design, however. He
assumes that the first couple of waves are the fundamental, but this
doesn't seem to be true, at least for my guitar. I think a DSP design,
using some simple digital filters, would make more sense. DSPs are
getting pretty cheap. You could tune all the strings simultaneously...

I know how you feel. It's easy to get lost in a first job. You want to
do well, and don't want to ask for help. However, I'd guess that your
ability to ask senior guys for help is one of the things they are
testing you on...

Regards, and good luck!
Bob Monsen