HDTenEightyP/NetNews huggingface dataset:
From: ornitz@kodak.kodak.com (Barry x24904/ER/167B-TED)
Subject: Re: Uneven microwave cooking ... why? 
Followup-To: sci.electronics
Summary: not just water
Keywords: microwave, water, spectroscopy, resonance, frequencies
Organization: Eastman Chemical Company
Distribution: net
Date: Tue, 26 Jan 93 23:41:04 GMT

In article <1993Jan26.125656.29958@doug.cae.wisc.edu> kolstad@cae.wisc.edu 
(Joel Kolstad) writes:
>Microwaves are tuned to heat up water most effectively, so things with
>little water in them (i.e., non-microwave popcorn) don't cook well.

I agree with almost everything said but this.  Microwave ovens are NOT
specifically tuned to any resonant absorption frequency of water.  Water
happens to be a good absorber over a broad range of frequencies.  The choice
of 2.45 GHz (in the US) for the operating frequency of home microwave ovens is
more an economic one and one dictated by international agreements.  915 MHz
is often used industrially in the US, and a myriad of other frequencies are
used in foreign countries.

This is a common misconception, and one that even tends to be propagated by
physics professors who should know better.  Water absorbs considerable
energy at frequencies used in microwave ovens, but so do many other materials.

For those who want further references, the best I can suggest is "Microwave
Spectroscopy" by Charles Townes and Arthur Schawlow. [Remember that before
the laser came the maser which was an offshoot of Townes work with microwave
spectroscopy!]

Let's kill the myth that microwaves heat only water and that the frequency is
a special one that resonates with water molecules.
					Barry
 -----------------
|  ___  ________  |    Dr. Barry L. Ornitz          WA4VZQ
| |  / /        | |    Eastman Chemical Company
| | / /         | |    ECC Research Laboratories, Engineering Research Div.
| |< < K O D A K| |    Process Instrumentation Research Laboratory
| | \ \         | |    P. O. Box 1972, Building 167B
| |__\ \________| |    Kingsport, TN  37662  (615/229-4904, FAX 615/229-4558)
|                 |    INTERNET:   ornitz@kodak.com
 -----------------
Newsgroups: sci.electronics
From: smckinty@sunicnc.France.Sun.COM (Steve McKinty - Sun ICNC)
Newsgroups: sci.electronics
Subject: Re: DC to AC on large scale???
Date: 25 Jan 1993 10:59:02 GMT
Organization: SunConnect
Distribution: world
NNTP-Posting-Host: hardy.france.sun.com

In article <30711@castle.ed.ac.uk>, ajmy@festival.ed.ac.uk (A Myles) writes:

> 
> The fact that we are 50Hz and France is 60Hz might be observed too. :)

Except that France isn't. It's 220v 50Hz, like most (all?) of Europe.


Steve

-- 
Steve McKinty
SUN Microsystems ICNC
38240 Meylan, France
email: smckinty@france.sun.com	   BIX: smckinty
Newsgroups: sci.electronics
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Uneven microwave cooking ... why?
Organization: U of Wisconsin-Madison College of Engineering
Date: 26 Jan 93 12:56:53 CST
Keywords: microwave

In article <ryu.728070649@husc.harvard.edu> ryu@husc8.harvard.edu (William Ryu) writes:
>	I was wondering what was the major cause of uneven microwave
>cooking.

The fact that it's extremely difficult to design a microwave source (or
just about any high frequency source) that provides a nice, planar
radiation coverage.  (This analogy is a little strained, but consider a
light bulb pointing in one direction [as in from the magnetron] -- trying
to get the light to all an entire box [the cooking compartment] evenly is
difficult.)

>  Is it a hardware problem or is it simply because most foods are
>inhomogenous and absorb the microwaves unevenly.

The inhomogeneity of the foods is somewhat of a problem, which is why we
have the proponderonse (sp.) of "microwave" brownies, pizza, etc.
Microwaves are tuned to heat up water most effectively, so things with
little water in them (i.e., non-microwave popcorn) don't cook well.

>  Also why do many frozen
>instructions ask you to turn the food or use one of those food spinners? 
>Is the distrubution of the microwaves that uneven.

Unfortunately, yes.

>  Last question.  My
>G.E. microwave has a antenna that spins right below the microwave top and
>is encased behind a plastic enclosure.  What does that do?

It's supposed to change the radiation pattern within the microwave so that
each part of the oven is exposed to a more even power level.  Same idea as
a turntable, but different implementation.  (Going back to the light bulb
analogy, it's similar to those rotating mirrored balls they have at discos.
:-) )

I don't know what "State of the Art" in microwave oven design is today, but
I can say that our 3 year old Sharp with a turntable doesn't suffer from
uneven heating caused by uneven radiation.  It does, of course, still
suffer from the fact that all the food's not a hot dog.

						---Joel Kolstad
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Date: Tue, 19 Jan 1993 20:11:20 GMT
Subject: Re: QUESTION: The R is out on my RGB monitor
Organization: Hewlett-Packard, Fort Collins, CO, USA
Newsgroups: sci.electronics

> 
> What would be the most like cause of this problem?
> 

Something died in the red video amplifier.  I'm assuming you tried your
computer with a different monitor, so that you know the red output is OK.
I't possible, but much more unlikely, that the red gun is out in the CRT.

The most likely thing, especially given that this is a new monitor, is that
you experienced a CRT "flashover" (internal arcing, common during the first
day or so of CRT life, esp. after it's moved) that took out the output
transistor of the red amp.  You might want to look for the simple things
first, though - make sure that the internal video cable (if any) is still
attached at both ends, and that the external cable (esp. if attached to the
monitor) is OK.  Wiggle the cables and see if the red flashes back on briefly.

Diagnosing the fault in the video amplifier should not be attempted unless
you know your way around high-voltage equipment with an oscilloscope.


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   Systems Technology Div.  |those of my employer or any other
myers@fc.hp.com    Fort Collins, Colorado   |sentient life-form on this planet.

Newsgroups: sci.electronics
From: kilian@cray.com (Alan Kilian)
Subject: Re: Stack (LIFO) Chips?
Organization: Cray Research, Inc.
Date: 25 Jan 93 17:04:16 CST


How about some more specifications?
If you are doing 8 bits and a reasonable depth and speed a small
PIC or Motorola MC68HC705K1 might be the ticket.
We just don't know yet that's all.
 
                 -Alan "Picky Picky Picky" Kilian

-- 
 -Alan Kilian           kilian@cray.com 612.683.5499 (Work) 612.721.3990 (Home)
  "Our friend Dirac has his own philosophy. It is:"
  "There is no God and Dirac is His prophet" - Some Physicist
From: ST201262@brownvm.brown.edu ()
Newsgroups: sci.electronics
Subject: vacuum tubes
Date: Mon, 25 Jan 1993 17:31:45 EST
Organization: Brown University - Providence, Rhode Island  USA
NNTP-Posting-Host: brownvm.brown.edu
X-News-Software: BNN via BNN_POST v1.0 beta

I'm looking for some vacuum tubes for an old Fisher receiver.  They are pretty
rare ones, so average supply stores don't usually carry them.
The tube number is 7591A, and I could use at least three of them.  They are
audio output tubes, and if anyone has any good clue on where I could find
them, or if anyone has any, please respond to this account.
Thank you very much for your help.

Mike Wolosin
st201262@brownvm.brown.edu

                          -Mike Wolosin
                           st201262@brownvm.brown.edu
From: VAN_HEEL@FHI-Berlin.MPG.DE
Newsgroups: sci.electronics
Subject: Electronic engineer from Bosnia seeks job in Canada
Date: 21 Jan 93 19:18:28 +0100
Organization: Rechenzentrum MPG Berlin





        Electrical engineer from Bosnia needs job in Canada



        Konstantin Hadziristic (44), 
        master's degree in electrical engineering,
        19 years of experience in energy conservation in industry
        (data acquisition, modelling, unit energy consumption
        and power demand analysis, management improvements)
        seeks suitable job offer in Canada (Edmonton?).

        Was forced to leave Bosnia with wife and 2 year old child, 
        and is temporarily living in Holland.

        A permanent resident visa for Canada is already available.

        Please phone directly:    011 (31) 5945-13095
        or reply by e_mail (see below)

        Konstantin Hadziristic 
        B.v. Waninglaan 49
        9351 LS   LEEK     
        The NETHERLANDS



==================================================================

      I am posting this for a friend.  Wil forward electronic messages
      by ordinary mail or FAX.

      Marin van Heel 

      Fritz Haber Institute of the Max Planck Society   
      Faradayweg 4-6, W-1000 Berlin 33, Fed.Rep.Germany 
      Tel: 49-30-8305380     fax: 49-30-8305509
      E_mail:  Van_Heel@fhi-berlin.mpg.de                
            


Newsgroups: sci.electronics
From: nagle@netcom.com (John Nagle)
Subject: Re: DC to AC on large scale???
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Date: Sat, 23 Jan 1993 17:59:14 GMT

ers1@cbnewsm.cb.att.com (eugene.r.schroeder) writes:
>In article <1jmre4INNfks@rave.larc.nasa.gov> kludge@grissom.larc.nasa.gov (Scott Dorsey) writes:
>>In article <1993Jan21.095254.62979@cc.usu.edu> slmdj@cc.usu.edu writes:
>>>He is an assistant city engineer for Adelanto, CA, and told me that the way
>>>their power is distributed to a large substation is Direct Current!  

>>They do it with silicon, believe it or not!  They have thyristor switches
>>taller than a man, and switch the DC.  This way, they can run DC on the
>>long lines at high voltage, which is advantageous since they get more
>>power over the same wire (since the limiting factor on the lines is the
>>peak voltage before arc-over, and the peak voltage on DC is also equal
>>to the average).

       Yes, there are thyristors that big.  First big power application
was a power line across the English Channel (submarine cable).  The
Continental and British grids aren't synchronized, and the proposed
tie wasn't strong enough to keep them synched, so they had to use DC.

       Thyristors are now available in sizes suitable for locomotive and
elevator power controls.  BART was the first rail system with solid-state
power controls, and it was a big headache in the early days.  Earlier
rail systems worked by switching motor windings around through various
series-parallel combinations, giving a limited number of speeds and
jerkey transitions.  There were, though, some "electronic" locomotives
in the 1950s that used ignitrons, which are a mercury-vapor device that
works like a thyatron or SCR.

       Have elevators all gone solid-state, or are systems with motor
generator sets still being installed?  Classical elevator control uses
a motor-generator set, with an AC motor and a DC generator, driving a
DC elevator controller.  The field current of the DC generator is adjusted
to control acceleration.  A generator has "gain" when used in this way.
This seems an obsolete approach, but there are certainly many still running.

					John Nagle
From: moisan@silver.lcs.mit.edu (David Moisan)
Newsgroups: sci.electronics
Subject: Sony KPR 4110 Projection TV has odd problem
Followup-To: poster
Date: 26 Jan 1993 16:41:53 GMT
Organization: MIT Laboratory for Computer Science
NNTP-Posting-Host: silver.ai.mit.edu
Summary: Pix are fuzzy..in an odd way!

My friend's Sony projection TV  (KPR 4110) has a strange problem:
The picture is fuzzy, in an odd way.  As he described it to me, it looks
like this:
 
 +--------------------------+
 !fuzzy               clear !
 !                          !
 !                          !
 !                          !
 !                          !
 !clear               fuzzy !
 +--------------------------+
 
The picture's fuzzy in the upper left and lower right corners of the 
screen;  it's OK in the other two corners.
 
He's not sure whether his model's a one-tuber or a three-tuber.  (He 
says it has numerous convergence controls, but that's not saying much
IMHO.)

Someone's always come through for me on this newsgroup.  Any suggestions
are appreciated, and thanks much. 

73's, Dave
-- 
| David Moisan, N1KGH    /^\_/^\   dmoisan@pro-angmar.alfalfa.com |
| 86 Essex St. Apt #204 ( o ^ o )  moisan@silver.lcs.mit.edu      |
| Salem. MA 01970-5225     | |                                    |
\-----------------------------------------------------------------/
Newsgroups: sci.electronics
From: msunde01@mik.uky.edu (Mark  Underwood)
Subject: Re: hard disk orientation
Reply-To: msunde01@mik.uky.edu
Organization: University Of Kentucky, Dept. of Math Sciences
Date: Tue, 26 Jan 1993 22:48:52 GMT

In article <C1GHnF.DGL@dcs.ed.ac.uk> gst@dcs.ed.ac.uk (George Taylor)  
writes:
> Could anyone tell me if running a hard disk vertically instead of  
horizontally
> (e.g.using a desktop machine on it's side like a 'tower' system)
> is likely to decrease it's lifetime?
> 
> -- 
> George

No, it's not, really.  I've checked manufacturer's specs on several models  
(e.g. Connor, Maxtor, Seagate) and they all say vertical mounting is fine.   
Just don't mount it upside down (I'm not sure why...)

Vertical mounting should have no effect on the disk as opposed to  
(upright) horizontal mounting, and may even be beneficial (the heads would  
be less likely hit the disks, I think... and any dust that might get  
inside would (?) settle to the "side" of the drive rather than onto the  
platters themselves.

Just my 2 cents worth

--
Mark Underwood
EE Student, University of Kentucky
Lab Assistant, Boyd Hall Microlab 
	(a tiny little division of UK Library Microlabs)
E-Mail:  msunde01@mik.uky.edu
From: kehoe@netcom.com (Thomas David Kehoe)
Newsgroups: sci.electronics
Subject: Re: How to make 24db passive bandpass filter?
Date: 26 Jan 93 17:05:41 GMT
Article-I.D.: netcom.1993Jan26.170541.20504
Organization: Netcom - Online Communication Services (408 241-9760 guest)

>Can anyone tell me how to make a passive band pass
>filter with a 18 to 24 db slope?  Is it just like

I'm ordering one from Digikey today.  I've tried to
make my own active filters from the section in
Horowitz&Hill, but they never sound better than
passive filters.  Apparently you need a dozen or
so poles, precise R and C values, etc.  The ones
in the Digikey catalog look simple: 4 pins, Vc,
ground, in, out.  $10 or so, a variety of values,
even some adjustable ones I think.
-- 
"Why my thoughts are my own, when they are in, but when they are out
they are another's." - Susannah Martin, hanged for witchcraft, 1692.
Thomas David Kehoe          kehoe@netcom.com         (408) 354-5926
Newsgroups: sci.electronics
From: dana@atlas.la.locus.com (Dana H. Myers)
Subject: Re: Power Amplifiers
Organization: Locus Computing Corporation, Los Angeles, California
Date: Thu, 28 Jan 93 15:58:59 GMT

In article <C1GzpH.E6I@inews.Intel.COM> crichmon@sedona.intel.com (Chris Richmond) writes:
>
>
>Ah, but consider an Intel 80C196 variety microcontroller.  It can generate the PWM
>signals or digitally drive a stepper, and has a built in 10 bit A/D for the
>analog feedback.
>

Having used the 8096 family, I would certainly encourage one to investigate
it.  The 80C196 is not only pretty fast as microcontrollers go, it has
a clean architecture, good set of on-cip I/O, and it is very nice to
program.


-- 
 * Dana H. Myers KK6JQ 		| Views expressed here are	*
 * (310) 337-5136 		| mine and do not necessarily	*
 * dana@locus.com  DoD #466 	| reflect those of my employer	*
 * This Extra supports the abolition of the 13 and 20 WPM tests *
Newsgroups: sci.electronics
From: cs000rjp@selway.umt.edu (Russell J. Pagenkopf)
Subject: How do I create a 2A load to test a power supply?
Organization: University of Montana
Distribution: sci.electronics
Date: Sat, 23 Jan 1993 23:55:48 GMT

Hi! I have a sealed power supply that I need to test for voltage and
amperage under load and this is my problem, how do I create a 2 amp load?
The power supply uses 120VAC 0.40A grounded and outputs (supposedly) 20V,
2.0A, 40VA Class 2  with four pins ( I have no idea what pins do what yet). I
understand that if I place my meter in series between the load and the
power supply, I should be able to read 20V (dc right?) and 2.0 amps. But
what does the 40va mean? 40VAC? I guess what this comes down to is, how
should I test this thing to make sure it is giving me what it should?

Thanks for any help and sorry for wandering ;-).

-- 
  Russ Pagenkopf	                          cs000rjp@selway.umt.edu
 School of Journalism, University of Montana         cs__rjp@lewis.umt.edu
<There is no other wisdom, and no other hope for us but that we grow wise.>
From: phys2108@waikato.ac.nz
Newsgroups: sci.electronics
Subject: Re: DC to AC on large scale???
Date: 22 Jan 93 13:42:37 +1300
Organization: University of Waikato, Hamilton, New Zealand

In article <1993Jan21.095254.62979@cc.usu.edu>, slmdj@cc.usu.edu writes:
> While visiting my uncle in Calif. over Christmas break, he posed a question for
> me... Just so I have an answer for him (and myself too... It's an odd one)
> could someone help me out???
> 
> He is an assistant city engineer for Adelanto, CA, and told me that the way
> their power is distributed to a large substation is Direct Current!  He said
> that the DC is then 'phased' or 'converted' so that there is a three-phase AC 
> line to the city distribution grid.  Neither of us have any idea how this could
> be accomplished at such power levels (an entire valley, I think!)
> 
> Thanks, 
> -- 
> ********************************************************************************
>       Paul Cowley      * ..."It's easier said than done."   And if you don't 
>    ==EE Undergrad==    * believe it, try proving that it's easier done than
>  Utah State University * said and you'll find that 'it's easier said that "it's
>   C/A1C  CAP Utah Wing * easier done than said" than it is done.'  Which really
>    slmdj@cc.usu.edu    * proves that it's easier said than done.
> ********************************************************************************
One way I believe they can do it is by using the dc to power a motor, which
then drives an ac generator.
Geoff.
Newsgroups: sci.electronics
From: ml3g@Virginia.EDU ("Mark  Lee")
Subject: WANTED: HP7047A XY Recorder
Organization: University of Virginia
Date: Thu, 21 Jan 1993 14:25:25 GMT

I am looking for a Hewlett-Packard 7047A XYT chart recorder,
the one with a static charged paper holder and .01 mV/in.
maximum sensitivity.  HP has not made this in nearly a decade.

If anyone has one in decent working order he/she is willing to
sell, please email me.  Or if anyone can suggest a source where
I might be able to find one.

--Mark Lee
marklee@virginia.edu
Newsgroups: sci.electronics
From: long@spk.hp.com (Jerry Long)
Subject: Re: Zenith TV Problem
Organization: Hewlett-Packard
X-Newsreader: TIN [version 1.1.4 PL6]
Date: Wed, 27 Jan 1993 20:29:49 GMT

Dru Nelson (dnelson@newssun.med.miami.edu) wrote:
: 
:   Hello,
: 
:      I got this set which started taking time to warm up.  


if TV is rather new, this probably is relative to the CRT heater
voltage. Does sound come on immediatly?


:      It makes a loud buzzing noise and creates sparks from
:      the ground "feelers" that touch the top right corner of the tube.
 
these feelers are usually for static charge bleed-off. If you are seeing
sparks from these, chances are the high voltage is present.

:      ... it leaves an ozone kind of smell.  My only guess is that it
:      is the high voltage/sweep module.
: 
again it sounds as though the high voltage is on due to the presence
of ozone. I would start with the main power supply advancing to the
secondary supplies which are part of the HOT circuity. 
It is also possible the HV has become non-regulated and sky-rocketing
which would also give lots of sparks, noise, ozone etc..


Good luck.

Jerry Long @spk.hp.com
From: bram@fangorn.hacktic.nl (Bram Smits)
Newsgroups: sci.electronics
Subject: batteries
Date: 26 Jan 93 04:40:24 GMT
Organization: Fangorn System
NewsSoftware: Rnf 0.73b

Just found a 12V NiCd accu pack. I guess I haven't charged it for about 
3 or 4 years. Do you think I can still put it in the charger and use it, or is
it lost ??

But now for the real question : I have a Toshiba T1000 portable, which wants
a 9V DC input from the charger. Can I just hook up an external 9V accupack
to the 'adaptor' input, or a >9V pack (like the one mentioned above) with a 
simple 7809 or LM317 based voltage regulator circuit, or would that damage the 
portable ?? It doesn't have interchangable batteries, so I don't have the 
option of buying 'official' extra accu packs.

If I can't use the accupack 'just like that' on the charger input, what kind 
of circuit would it take to achieve that ??

Cya,

    v__   
  <"___\____     Bram 'mouser' Smits.

-------------------------------------------------------------------------------
| All views expressed herein are my own, etc, etc. | Fangorn Systems          |
| All disclaimers apply.                           | Heerlen, The Netherlands |
-------------------------------------------------------------------------------
Newsgroups: sci.electronics
From: hyx1@cunixb.cc.columbia.edu (Harry Y Xu)
Subject: Re: Heathkit
Reply-To: hyx1@cunixb.cc.columbia.edu (Harry Y Xu)
Organization: Columbia University
Date: Tue, 26 Jan 1993 03:24:48 GMT

>	Heathkit's order by phone number is:
>	(800) 253-0570
>	
>	Call them for a catalog...
>
>	They also have a FAX number. It is:
>	(616) 925-4876

Their # for catalog request is 800-444-3284, leave message.
I called twice over 2 monthes, the catalog never came!!!
-Harry Xu (KB2LHA/AE)
Newsgroups: sci.electronics,misc.wanted,rec.video
From: bj@mcanix.inmos.co.uk (John Honniball)
Subject: Looking for Philips VR2020 VCR tech manual
Keywords: Philips V2000 schematics
Reply-To: bj@mcanix.inmos.co.uk (John Honniball)
Organization: INMOS IQ Systems Group, Bristol, UK
Date: Wed, 27 Jan 1993 16:45:30 GMT


Well, I acquired yet more electronic "junk" at the weekend!  This one's
a 1980 Philips video cassette recorder, model VR2020.  It takes the
amazing Philips "VCC" or "Video 2000" tapes which I believe are unique
in that you can turn them over and record on the other side!

Now the bad news is that the machine's servo system seems to be faulty
and Philips no longer supply manuals or circuit diagrams (schematics).
The symptom of the fault, BTW, is that the sound is OK, but the video
won't sync up in the vertical direction.

So, does any one know where I can get a manual/circuit for this thing?
Thanks in advance...

--
BJ. (John Honniball)

INMOS Ltd., 1000 Aztec West, Bristol, UK.

bj@inmos.co.uk      -or-       bj@inmos.com
From: whit@carson.u.washington.edu (John Whitmore)
Newsgroups: sci.electronics
Subject: Re: Voltage drop across 1N4148 diode?
Summary: 1N5817 is OK for powering SCSI terminators
Date: 25 Jan 93 23:44:36 GMT
Article-I.D.: shelley.1k1u14INNlkk
Distribution: world
Organization: University of Washington, Seattle
NNTP-Posting-Host: carson.u.washington.edu

In article <24JAN199300065341@rosie.uh.edu> st1my@rosie.uh.edu (Stich, Christian E.) writes:

>a Schottky diode has been mentioned several times so I am looking into
>replacing the 1N4148 (which is too small, that's why I asked) with another
>diode is rated at up to 1A and has an as small as possible forward voltage
>drop    ....I'd like to find a Schottky diode that has a max. reverse
>current in the micro Ampere instead of mA range.
>This diode is used on the TERMPWR (SCSI-bus) line to prevent an external
>device from powering the computer

	SCSI devices have relatively high currents in their power
supplies (the SCSI drivers have fourteen 48 mA drive outputs),
so a milliampere of leakage will be NO problem.  In fact, it is 
unlikely that you will see that much leakage current (the
diode is specified for power-supply operation, at full maximum
operating temperature).  

	John Whitmore
Newsgroups: sci.electronics