magnetic field

[Badger]

On Sun, 06 Feb 2005 04:56:37 GMT, Steven O. <null@null.com> wrote:

[snip]

But here is how the math works out for me:

a = (1/R)(dR/dT)

dR/R = a dT Take indefinite integral of both sides....

ln R = a T + Ts, where Ts is said reference temperature

I'll make a guess here that your "constant of integration"
could be ( - a Ts ), so that

ln R = a T - a Ts = a (T - Ts)

exp[ ln R ] = exp[ a (T - Ts) ]

exp[ a (T - Ts) ] = 1 + a (T - Ts) approx., so that

R = 1 + a (T - Ts)

If the Prof will buy into that, then

Assume R1 corresponds to T1, and R2 to T2, then....

ln R1 = a T1 + Ts, and ln R2 = a T2 + Ts

R1 = a (T1 - Ts) and R2 = a (T2 - Ts)

R1/R2 = [ a (T1 - Ts) ] / [ a (T2 - Ts) ]

R1 = { [ a (T1 - Ts) ] / [ a (T2 - Ts) ] } R2


As I said, just a guess on my part, FWIW.

 

[Chaos Master]

This is Uno for forever:

Should we up grade our computer to 64 bits CPU now?

It depends:

- If the applications you use can make use of 64-bit instructions (I
don't know examples... maybe video/image editing programs), yes

- If you can compile applications for this CPU, yes

- If the operating system you use provides 64-bit support (e.g. Linux,
FreeBSD, 64-bit Windows XP?)

- I remember seeing that 64-bit Windows XP will not support 16-bit
applications anymore.


--
Chaos MasterŽ, posting from Canoas, Brazil - 29.55° S / 51.11° W / GMT-
2h / 15m

"He [Babya] is like the Energizer Bunny of hopeless newsgroup
posting....or should that be Energizer bBunny"
- "ceed" on alt.comp.freeware, 24/1/2005

(to some groups: Yes, I use Windows and MS Office. So what?)

 

[Uwe Hercksen]

CWatters schrieb:

Here's an idea though. I think some countries like Switzerland and Japan
have a mix of 50/60Hz. If their web sites ask which frequency you have then
it's a good bet that it matters.

http://www.gbaudio.co.uk/data/mains.htm

Hello,

it seems to be an error in thtat table, look here for Switzerland:
http://kropla.com/electric2.htm

All countries within the European power net use 50 Hz.

Bye

 

[Uwe Hercksen]

x@nospam.com schrieb:

Thanks for the tip about Switzerland. The chart I was looking at didn't
list them as having 2 different frequencies.

Hello,

the chart was correct. The tip is wrong. Only Japan has 50 and 60 Hz.

Bye

 

[Jim Thompson]

On 7 Feb 2005 18:57:17 -0800, Winfield Hill
<hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote:

[snip]

I'll find a good one for comparison.

Win, Did you ever get anywhere with comparing the MOSFET models?

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Winfield Hill]

Jim Thompson wrote...

Win, Did you ever get anywhere with comparing the MOSFET models?

Thanks for the reminder.


--
Thanks,
- Win

 

[Jerry G.]

When sending to news groups, please make sure that you do not send in full
HTML. Many of the news readers cannot read full HTML. Also, there are
security issues when using HTML.

--

I would wait a while. There is no real support, other than some specialized
software's that have been written for the 64 bit format. It would be best to
wait until the 64 bit format is the main standard for PC machines.

I believe that AMD were the first ones to have a 64 bit system.

--

Jerry G.
=====

"Uno" <uno@max.com> wrote in message
news:a2BNd.1239$5G7.237@newssvr31.news.prodigy.com...
Should we up grade our computer to 64 bits CPU now?

 

[Sporkman]

Ruediger wrote:

(There is a beer in Germany nicknamed "Bit" , Bitburger Pils-Beer....
And there is a joke at my university: no wonder our 64-Bit Systems seem to
fly... with 64 Bit I would also feel like flying! )

OUTSTANDING beer . . . was one of my favorites. From the Eifel area,
IIRC.
Bitte, ein Bit!

 

[R.Lewis]

"zooeb" <zooeb@libero.it> wrote in message
news:62b9dcf3.0502091225.1660366e@posting.google.com...

in a simple electric circuit, in which you have a DC voltage
generator, an internal resistence and the resistence of the load, why
the maximum power that the generator is able to tranfer to load is
when load resistence is equal to internal resistence? I try to think
about it: if internal resistence is zero, power developed by load is
V*I, where V is the voltage generator and I=V/RL; then if the internal
resistence goes up, the power developed by load is V*I, where V minor
than the voltage generator and I=V/(RI+RL), which is less then the
previous current. So, why in the first case power isn't max?

If the internal resistance of the source is zero ohms and the load resitance
is equal to the internal resistance then the power is infinite.
Difficult to get any higher than that.

Otherwise do some sums.
If I have a 12v battery with an internal resistance of 6ohms and I connect a
6ohm load resistor to it the power dissipated in the load is 6 watts.
Just try any other value of load resistance and see if you can get its
dissipation above 6 watts.

 

Does it have to look nice?

If not, find your local Unistrut distributor, get a short length of
channel and a single nut.

Tim.

 

[Joerg]

Hello Tim,

Does it have to look nice?

If not, find your local Unistrut distributor, get a short length of
channel and a single nut.

I'd guess that Mrs.Thompson would voice objection here ;-)

Regards, Joerg

http://www.analogconsultants.com

 

[Jim Thompson]

On Thu, 10 Feb 2005 01:52:47 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hello Jim,

Do you still have the screw drive from the old opener? There are usually
limit switches at both ends which can be freely moved along the aluminum
track. They also have set screws. You should be able to mount the LED
beam to one of these brackets unless it is really heavy.

We had the same problem, back in Europe. A huge Audi station wagon that
had to be parked just right and two inches from the far end or you
wouldn't even be able to get out. When we moved into this house I
couldn't believe that they called it a two car garage. You could park
two Texas Cadillacs in there and still have 10 feet left.

Regards, Joerg

http://www.analogconsultants.com

Illuminating the dash puts the LED about 2' toward the wall past the
opener location. The mount of the old Genie Screw Drive (Junkus
Maximus had angle iron sticking out that far.

I just put in two Chamberlain belt drive units... nice and quiet.
Guaranteed forever. Installer told me that he had been installing
them for 13 years... never replaced a single belt.

I'm (I think) going to use 1/2" thin wall conduit hung from the
ceiling with conduit hangers, and a hanger to hold the LED mechanism.

I have two doors, one a two-car and one a single car width. The
garages are amply wide... open the car doors fully. Just the peekup
truck and Q45 length are such that proper parking avoids banging knees
on bumpers ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Paul Burke]

Joerg wrote:

Illuminating the dash puts the LED about 2' toward the wall past the
opener location.

High-tech. I have seen people using a simple rope and tennis ball that
touches the windshield when the car is just parked right. It's power
outage proof ;-)

Our village, having been laid out 400 years ago, lacks off- street
parking. My car is in exactly the right place (to leave enough room for
the neighbour's) when the C of "to the Church" is obscured by the
nearside roof pillar.

Paul Burke

 

[tlbs]

We build avioncs for space applications. There are several
manufacturers of military quality electyrolytics. AVX, Kemet, and
Vishay are a couple that come to mind right away. You can even order
parts with proven established reliabilities rated at 10 failures per
billion hours (in the proper application).

AVX even has some commercial components that are in the single-digit
per million hours category of reliability.

Some of the GPS satellites have been operating in a very harsh
radiation environment 24/7 for 15 years, now, using these types of
parts.

Two things you can do to increase the reliability of capacitors;
increase the working voltage of the capacitor relative to the operating
voltage (less stress on the capacitor), and operate the capacitor at a
constant temperature in the middle of its rated range.

 

[Joe Soap]

In response to what <mmayers@gmail.com> posted in
news:1108333365.788141.55630@g14g2000cwa.googlegroups.com:

I have some LEDs, resistors, and a breadboard. I want to write a
program that will make the LEDs flash in certain sequence (they are
attached to the board.) i have to proper resistors and everything so i
won't damage anything (i hope). i want to connect the breadboard to the
PC through my parallel port, however, i am having a helluva time
finding a device to do this. can someone point me in the right
direction.

I am going to school for computer science. i am certainly no electric
engineer, but i hope to learn.

you will need to be running W95 or W98 or earlier (or DOS), W2000/XP lock
us out of our own parallel ports. Thanks a lot Bill.

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

 

[CWatters]

"CWatters" <colin.watters@pandoraBOX.be> wrote in message
news:hYkPd.9732$nF.517187@phobos.telenet-ops.be...

"Etantonio" <etantonio@gmail.com> wrote in message
news:467ddbce.0502110009.d9c332b@posting.google.com...
Hi,
I'm writing from a Gericom Webshox portable computer of 2001,
now the battery pack ( UN241S1 Rechargeable Li-Ion Battery Ratings:
14,4Vdc 3600mAh )
is broken son I decide to change the accumulators,
I choose 8 NiMH 3,6Ah 1,2V Accumulator.

Mistake.

1) Li cells need constant voltage charging.

I should clarify that a bit...

At the start of the charge cycle they need constant current and once the
voltage rises they need constant voltage.

 

[John Woodgate]

I read in sci.electronics.design that Jim Thompson
<thegreatone@example.com> wrote (in <nvsu019pd68i3idjo95lvs99noipp3b2ak@
4ax.com&gt about 'OT: LG-VX6100 Cellular Phone', on Sun, 13 Feb 2005:

I've even taken to NOT forwarding my land line when I go to lunch...
east coast clients seem totally incapable of telling time ;-)

Or do they just forget that your lunch hour is from 1130 to 1530? (;-)
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[James]

James wrote:

I need a new power supply for my anodising station. This needs to be cheap
and chearfull so I'm thinking about building one. Does anyone have a
schematic for this? Its got to have current control but doesn't need volt
control. I would like it at least 20A (more if feasible).

Thanks!

BUMP - any ideas?

 

[James]

Jamie wrote:

James wrote:

James wrote:

I need a new power supply for my anodising station. This needs to be
cheap
and chearfull so I'm thinking about building one. Does anyone have a
schematic for this? Its got to have current control but doesn't need
volt
control. I would like it at least 20A (more if feasible).

Thanks!



BUMP - any ideas.


http://www.valcoelectronics.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=VE&Product_Code=PS36&Category_Code=0034


and a few others there.

Thanks but there is no current control on those

 

[Jamie]

James wrote:

James wrote:

I need a new power supply for my anodising station. This needs to be
cheap
and chearfull so I'm thinking about building one. Does anyone have a
schematic for this? Its got to have current control but doesn't need volt
control. I would like it at least 20A (more if feasible).

Thanks!



BUMP - any ideas.

http://www.valcoelectronics.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=VE&Product_Code=PS36&Category_Code=0034

and a few others there.