HDTenEightyP/NetNews huggingface dataset:
Newsgroups: sci.electronics

> >:
> >:Intentionally discharging nicads to avoid "memory" is a waste of both time
> >:and cells.
> >:
> 
> But my latest Motorolla flip phone contains instructions telling me to
> periodically fully discharge the nicad batterys in order to keep their
> capacity from diminishing.  
> 
> Maybe you should talk with your battery folks and decide on a consistant
> story....
> 

Actually, I was they one who originally wrote the above, and as you can see,
I'm not from Motorola.  I still stand by the original statement, for reasons
presented ad nauseum in other postings.


Bob Myers            | "Man will occasionally stumble over the truth, but  
myers@fc.hp.com      |  most of the time he will pick himself up and continue."
                     |                        - Winston Churchill             
Newsgroups: sci.electronics,comp.sys.mac.hardware
From: scott@psy.uwa.oz.au (Scott Fisher)
Subject: Re: PowerBook 100 LCD screen replacement, the sad conclusion
Organization: University of Western Australia
Date: Mon, 17 Aug 1992 03:20:03 GMT

tcmay@netcom.com (Timothy C. May) writes:

>The 100 does not seem to be holding up as well as I'd hoped. Your tale of
>the cracked case reinforces this feeling I have.

On the week-end I watched a "science" special on the new palm-top, cray-in-a-
portable-pc type programs.  One thing that struck me (as I watched this woman
walking around outdoors with a pen-based system costing around $15,000) was
what happens when you drop one of these things.  Dropping your $50 calculator
is fine, but making $10,000 plus toys portable scares me :-)

Regards Scott.
_______________________________________________________________________________
Scott Fisher [scott@psy.uwa.oz.au]  PH: Aus [61] Perth (09) Local (380 3272).                
                                                             _--_|\       N
Department of Psychology                                    /      \    W + E
University of Western Australia.                 Perth -->  *_.--._/      S
Nedlands, 6009.  PERTH, W.A.                                      v       

    *** ERROR 144 - REBOOT? is a registered trademark of ENSONIQ Corp ***
-------------------------------------------------------------------------------
Newsgroups: sci.electronics
From: massoud@chemteca.sdsu.edu (Massoud Ajami)
Subject: Re: How slow are halogen lamps?
Organization: San Diego State University
Distribution: sci
Date: Sat, 22 Aug 1992 16:38:48 GMT

In article <1992Aug21.225605.17036@sics.se> boortz@sics.se (Kent Boortz) writes:



>I have noted that when halogen stage lights go of (500-2000W) there is
>a delay before the light is gone. Is the response to voltage changes slow
>for halogen lights? I was thinking of controlling a TRIAC with a
>microcontroller and one idea is to use patterns of AC half periods that is
>on or off. A 50% setting would be one halfperiod (hp) of and one on.
>A 75% setting would be 3 hp's on and one off. Switching the TRIAC on and
>off at the zero crossing point would eliminate the need for filtering away
>unwanted electro-magnetic interference.

>The problem is flickering for low settings. A 10% setting will give 9 hp's
>off and one hp on. But if the halogen lamp is slow in response it will
>eventually be no problem. Anyone know?


>Kent Boortz
>boortz@sics.se
>--
>Kent Boortz
>boortz@sics.se

Halogen lamps have no delay in turning off, it is the temperature of the 
filament which shows such action. If you increase the temperature of a 
normal light bulbe with tungsten filament (increase the current), the 
tungsten starts to vaporize, and it coats a film on the glass shell. This 
action reduces the intensity of the lamp, so defeeding the purpose of 
intensifying the light (any burned lamp has a black spot on the glass or 
somewhere else). By putting halogen gas in the tube, halogen will bring 
the vaporized tungten back to the fillament, so there wouldn't be any 
coating, therefore, you can run the filament in higher temperature, and get 
brighter light.

Pulsing the lamp does not let halogen lamp act as halogem lamp (low filament 
temperature), and also to some extend, the filament integrates the 
pulsation, and no flickering happens.


Peace and Prosperity!
  ---==< 110 >==---
Newsgroups: sci.electronics
From: ssomaroo@unpcs1.cs.unp.ac.za (Shyamal Somaroo)
Subject: Computer monitor - help needed?
Summary: Computer monitor --- I need help?
Keywords: monitor
Organization: Univ. Natal, Durban, S. Africa
Date: Wed, 19 Aug 1992 20:23:39 GMT

I used to own a Commodore 128 computer and had a monitor for it.
Now I use the monitor as a television screen and wonder if it
is possible for me to use it with my CGA card since I have a black
and white screen at the moment.

Also if it is possible could I use it with a VGA card and if so
how do I do it?

Can somebody help?

Send replies to somaroo@unpsun1.cc.unp.ac.za
or ssomaroo@unpcs1.cc.unp.ac.za

Advance Thanx
Newsgroups: sci.electronics
From: mpaul@unlinfo.unl.edu (marxhausen paul)
Subject: Re: What's a good price for a 4 channel 100 MHz analog scope?
Organization: University of Nebraska - Lincoln
Distribution: na
Date: Sat, 22 Aug 1992 13:24:39 GMT

As the EE Shop for the Universities engineering college, we periodically have
to advise on buying scopes, sometimes a whole student lab full (12 per lab).
So we keep our eyes open for good values and what we hope will be less expen-
sive brands: Leader, Hitachi, etc.  We've seen some nice stuff from all these
places, and we do have some nice inexpensive Hitachis we like, though I wish
they were a bit brighter in the trace.
But...we've just been getting deals from Tektronix that are hard to pass up.
They really aren't the high priced alternative anymore, they make a number of
lower-end scopes whose prices were as good or better than equivalent stuff
from other manufacturers.  And since we have to repair all of these widgets,
the fact that the Tek scopes are well made and have superb technical documen-
tation is crucial.  (Yes, I've worked on some older Tek scopes that were a
stinking nightmare to service.  They've improved.)  They certainly aren't
resting on their laurels...
  Of course, HP makes some mind-boggling scopes with DC-to-blue-light response
and stuff like that - along with a price that would buy you a small house
in this city.  But when you get into that realm, I've found there are times
when something as simple as a bad BNC connector could not be repaired by our
shop because it was so buried in heavily shielded construction, and because
it seems like a lot of HP stuff assumes that there's no way a lowly electronics
tech in a service shop is going to be able to fix it, so they've stopped being
so detailed in their tech literature.  The alternative is to send it back to
HP, where they charge some truly breathtaking flat repair fees regardless
of the problem.  But if you can afford one of these scopes, I imagine you
can afford the repair fees...
--
===============================================================================
paul marxhausen                              \/               grace 
university of nebraska - lincoln             /\              happens           
===============================================================================
From: jimc@tau-ceti.isc-br.com (Jim Cathey)
Newsgroups: sci.electronics
Subject: Re: "Super-CD" ... soon ?
Date: 15 Aug 92 14:53:37 GMT
Organization: ISC - Bunker Ramo, Spokane, WA

In article <2460@ulysse.enst.fr> krueger@cal.enst.fr (Martin Krueger) writes:
>1)  On the upper end of the theoretical 90dB range they have to cut off 10dB
>as a clipping reserve, since digital clipping would immediatly destroy a
>whole recording.

Who says that the original recording has to be done with (only) 16 bits?
Using 17 would make the problem go away --- just post-process the recording
to do a 'nice' clip and/or scale the recording to fit the intended output
medium.

Don't mistake what may be current practice for an inherent limitation.

-- 
+----------------+
! II      CCCCCC !  Jim Cathey
! II  SSSSCC     !  ISC-Bunker Ramo
! II      CC     !  TAF-C8;  Spokane, WA  99220
! IISSSS  CC     !  UUCP: uunet!isc-br!jimc (jimc@isc-br.isc-br.com)
! II      CCCCCC !  (509) 927-5757
+----------------+
			"PC's --- the junk bonds of the computer industry"
Newsgroups: sci.electronics
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: AC zero cross detection?
Organization: U of Wisconsin-Madison College of Engineering
Distribution: sci
Date: 21 Aug 92 18:03:26 CDT

In article <1992Aug21.222100.15735@sics.se> boortz@sics.se (Kent Boortz) writes:
>
>Hi,
>
>I will interrupt a microcontroller at 220V AC zero crossing time to reset
>an internal timer. Any ideas of a simple but reliable zero crossing detection
>circuit? The triggering has to be isolated with a optocoupler. The 220V
>will beside driving a halogen lamp be transformed down to 9V AC to drive
>the processor etc. Could I detect the zero crossing point on the 9V side
>or will there be a phase shift because of the induction in the transformer
>and the load?

You can just run that 220V AC straight to an opto-coupler through a BIG
resistor.  (220K comes to mind...)  If your opto-coupler only transfers
in one direction (i.e., there's only one LED inside instead of 2 back to back),
you should make sure that that LED can handle 220*1.5V reverse voltage.  It
probably can't, so you'll need to use an extra diode.

I've used some cheap NEC optocouplers (sold by DigiKey, page 77 in their
catalog) to do this.  (I used the 2502 and 2506 models -- they have Darlington
outputs so that you only _need_ 1ma of that 220V, and the less 220V I need,
the happier I am!)  The output is rather distorted (they aren't perfectly
linear).  What you want to do, though, is run this through a series
capacitor so that you get a differentiator.  Now, feed those pulses to a
comparator, and you'll all set!

As for the second question... yes, you could take the zero crossing from the
low voltage side.  And yes, it _could_ be out of phase depending on your
transformer and the load.  It may be best to look at the voltage vs. current
on an o-scope and see if you care...

I assume that you want to do more than just get a timer reset pulse though,
right?  If you use that timer to, say, control pulses to a TRIAC or something,
the low voltage side will most definitely look different that the primary.
(And if you _are_ firing TRIACs, remember to put some filtering into your
system so that we can all still listen to our radios without too much 
static. :-) )

						---Joel Kolstad


Newsgroups: sci.electronics
From: Josef Moellers <mollers.pad@sni.de>
Subject: Re: Want to build an EEG
Date: Thu, 13 Aug 1992 07:09:33 GMT
Organization: Siemens Nixdorf Info.Sys. AG, Paderborn, Germany

In <1992Aug11.145924.4335@truevision.com> Bob Zigon <bobz@truevision.com> writes:

>I have a data acquisition board on my PC. Conceptually, I want to "stick
>those
>little white patches on my head and digitize my brain waves". How many
>channels
>of information do I need? How do I build such a device?

Steve Ciarcia has had a project called "HAL", a "brain wave analyzer".
Look into back issues of BYTE (You know, the magazine that _used to_
care for the experimenter, now only cares for the "power user")!
-- 
| Josef Moellers		| c/o Siemens Nixdorf Informationssysteme AG  |
|  USA: mollers.pad@sni-usa.com	| Abt. STO-XS 113	   | Riemekestrasse   |
| !USA: mollers.pad@sni.de	| Phone: (+49) 5251 835124 | D-4790 Paderborn |
Newsgroups: sci.electronics
From: aescherm@iastate.edu (A Person of Awareness)
Subject: Re: Craftsmanship is dying
Organization: Iowa State University, Ames, IA
Date: Fri, 14 Aug 1992 11:10:53 GMT


The way that I solve the problem of New is Bad/Old is Good is to buy those
old things that were good and fixable and those new things that I don't care
if I can or can't fix.

Really, if I'm buying a $5 pair of walkman headphones, who cares if they
break?  BTW I actually had a Radio Rip Off Store sales-droid offer me a plan
where for like $20 I could replace the headphones up to so many times in so
many months.  What if they didn't ever break?  Then I would have spent $25
on a $5 pair of headphones.  Silly.  Maybe good for runners, but I'm a sit-
in-chair-and-program-until-my-eyes-fall-out-of-my-head type person.  I don't
break headphones very often.

On the other hand, I require that my computers be repairable quickly and at
minimal cost.  I'm willing to accept 'obsolete' technology to accomplish this.

My current machines are an ORIGINAL IBM PC, an old Canon XT clone and a Mac
SE.  All of which, except the SE sort of, are very repairable.  In fact, I
spend alot of time doing that.  =-)  They cost, however, almost nothing to
repair.  In fact I have a friend who owns a reseller place.  If I have a bad
part I take it to him and he finds the same part and gives it to me with
the knowledge that I'll deal with him on big purchases (by big I mean $100)
in the future.  =-)   Now THAT'S service.  He even helps to fix my machines
for free because he knows I'll come back.  You can't get that from any other
place in my town.  ($40/hour to do something I could do myself if I had time?)

Anthony Clifton


Newsgroups: sci.electronics
From: alavigne@bmerh930.bnr.ca (Andrew Lavigne)
Subject: Looking for a thermo-electric cooler....
Organization: Bell Northern Research
Distribution: na
Date: 17 Aug 92 09:25:13


I'm posting this for a friend who is trying to build a CCD camera for his
scope.  He wants to know where he can obtain a thermo-electric cooler for
his CCD chip.  Its also known as a 'peltier cooling module'.  Does anyone
know where these can be obtained and about how much they are???

Any replies or hints appreciated...

Thanks,
Andrew
alavigne@bnr.ca
From: 10666281@eng2.eng.monash.edu.au (KEVIN PRATER)
Newsgroups: sci.electronics
Subject: "Chip chat" AY-3-1015
Date: 19 Aug 92 07:13:49 GMT
Organization: Faculty of Engineering, Monash University

I ve just dug out an old project for an xy plotter
from electronics and wireless world dec 1984.
It had a chip marked AY-3-1015 which they said was a uart chip.
can I substitute a NS16450 at uart for this?
And has anyone know the address of EWW  or the original full circuit
diagrams? 
thanks 
Kevin Prater
From: ken@sugra.uucp (Kenneth Ng)
Newsgroups: sci.electronics
Subject: Re: GPS questions
Keywords: GPS
Date: 19 Aug 92 03:24:34 GMT
Organization: Private Computer, Totowa NJ

In article <greg.714049408@coombs:, greg@coombs.anu.edu.au (Greg Price) writes:
: Hi, I have a couple of questions about how GPS works, but no-one know the
: answer too around here. See if you can help me here....
: 1) How does the receiver separate out the different signals from a number
:    of satellites if they are all transmitting on the same frequency (using
:    180 degree phase modulation) and using one non-directional antenna?

The short answer is that they aren't.  The long answer is that they are using
spread spectrum technology to module the signal.  Each satellite transmits
with a different pattern of frequencies, called Gray codes.  The challenge
is for the reciever to lock onto and track each of the satellites that are
within range.

: 2) The satellite has an accurate internal clock, and the receiver has
:    another internal clock which it syncs with the satellites, and uses
:    the propagation delay to determine this distance. How do you initially
:    sync the receiver clock with the satellites from scratch?

You don't.  The time in the receiver is generated via techniques that I
currently do not understand, but appear to generate a kind of 'virtual time'.
Each satellite transmits a kind of "I am here at this time".  The receiver
generates a 'virtual time' to figure out where and when it is.  As a spinoff
GPS allows you to get a time very close to UTC.

-- 
Kenneth Ng
Please reply to kdn5669@hertz.njit.edu for now.
Apple and AT&T lawsuits: Just say NO!
Newsgroups: sci.electronics
From: markh@csd4.csd.uwm.edu (Hunk)
Newsgroups: sci.electronics
Subject: Re: Craftsmanship is dying
Date: 12 Aug 92 15:34:10 GMT
Organization: Computing Services Division, University of Wisconsin - Milwaukee

In article <MOTOYAMA.92Aug11183427@harlgw92.harl.hitachi> motoyama@harl.hitachi (Hiroshi Motoyama) writes:
>However, I am very happy with looking at a silver plated logarithmic 
>variable capacitor driven by sophisticated gears, hand wound OSC coils on 
>white ceramic bobbins. Yes, all of those things are obsolete today when 
>craftsmanship in electronics is dying, or at least, getting invisible.

Craftmanship is in human nature.  That's why it will come back.

Therefore the following scenario is inevitable: chip manufacturing facilities
converted to public utilities along the same lines as water, gas, and
electricity, maybe under regulated private ownership.  The basic costs are
supported in the public sector, and (affordable) user fees are charged for
those who want to make one or a whole batch of new chips.

Chip designing systems are made freely available, chip manufacture orders
can be placed over telecommunications networks.
From: kevins@hpspdla.spd.HP.COM (Kevin G Smith)
Date: Thu, 13 Aug 1992 19:00:40 GMT
Subject: Precision Standard Time Co. Address/Phone??
Organization: HP Stanford Park - Palo Alto, CA
Newsgroups: sci.electronics

Hello,

I am trying to track down the Precision Standard Time company
which used to make WWV radio synchronized clocks.  A friend of mine's
university research group owns several of PST's radios and would like to 
purchase more but can't seem to find them.  

Does anyone know if they still exist, and if so, what their current
address and phone number is?  Or if they have been purchased,
merged, or gone belly up?  Thanks in advance for any clues.

Cheers,
Kevin

*******************************************
* Kevin G. Smith                          *
* Hewlett-Packard, Stanford Park Division *
* P.O. Box 10151, Mail Stop 5M            *
* Palo Alto, CA 94303                     *
* Phone: (415) 857-3423                   *
* FAX:   (415) 813-3085                   *
* Email: kevins@hpspd.hp.com              *
*******************************************
Newsgroups: sci.electronics
From: tidedu@lims01.lerc.nasa.gov (WILLIAM DEDULA)
Subject: LCD Displays
News-Software: VAX/VMS VNEWS 1.41    
Organization: NASA Lewis Research Center
Distribution: usa
Date: 21 Aug 1992 22:05 EST  

Hello;
I am having a hard time finding the type of Liquid Crystal Display which I 
need. A am building a circuit which must begin at 10 and count down to 0 
using a LCD display. So far, the only LCD displays I can find (And I've 
looked a lot) either require an analog signal, or they are controlled via. 
a computer. I require a display where the individual segments of each 
digit can be controlled so I can use a LCD driver chip (If one exists) 
to convert a BCD input (From a Binary Counter Chip) to a digital display. 
Is this capabibility available with a LCD display ? If so, could you 
recommend manufacturers of the LCD display's themselves, as well as the 
Driver Chips. 

Thank You Very Much !!!

Tim Dedula

NASA Lewis Research Center
Mail Stop 77-3
21000 Brookpark Road
Cleveland, Ohio 44135

216-433-3668
From: mcovingt@athena.cs.uga.edu (Michael A. Covington)
Newsgroups: sci.electronics
Subject: Re: What's a good price for a 4 channel 100 MHz analog scope?
Summary: Never mind, I want to know the name of your bank!
Date: 21 Aug 92 04:45:56 GMT
Distribution: na
Organization: University of Georgia, Athens

In article <1992Aug21.042535.5308@julian.uwo.ca> wlsmith@valve.heart.rri.uwo.ca (Wayne Smith) writes:
>We're looking at a Tektronics (model 5045A?) 100 MHz 4 channel
>analog scope that will cost us $2250 (can) or say $3085 (us).
>What would fit our bill a little better would be a 4 channel 20
>or 30 MHz job.  So...

Who gives you an exchange rate of 1.37 on Canadian to US dollars?
I was in Canada last week and the rate was 0.83...!



-- 
+ Michael Covington - Artificial Intelligence Programs - U of Georgia - USA 
+ Unless otherwise noted, these are private opinions, not official statements.
+ VOTE NO GEORGIA LOTTERY - don't tie education to an unpredictable income.
From: splee@gnu.ai.mit.edu (Seng-Poh Lee)
Newsgroups: sci.electronics
Subject: Questions about Dolby Surround Sound and Pro Logic
Date: 18 Aug 92 13:01:12 GMT
X-Newsreader: Tin 1.1 PL4

Can anyone provide me with the difference between plain old Dolby Surround
Sound and Dolby Pro Logic?

Also, what is the basic technique used by each system?

Thanks a lot

--
Seng-Poh Lee    <splee@gnu.ai.mit.edu>
From: demcma@bb1t.monsanto.com
Newsgroups: sci.electronics
Subject: HELP with remote swith please
Date: 12 Aug 92 11:20:58 CST
Organization: Monsanto Company, St. Louis, MO

Let me start by admitting to the a nearly illiterate in electronics.  I'm
currently trying to use a RF wireless remote control set up (Woods No. 1474)
which operates under FCC Rule Part 15.  Purchased at K-Mart, it is intended for
switching a lamp or other low-load device indoors with an advertised range of
50 ft.  I'm using it with an appropriate relay to switch a motorized winch for
pulling my plane back in its hangar.  This requires that I be at the front of
the plane (about 70 ft. away) to guide it via a towbar during the operation. 
I've mounted the receiver about 10-12 ft. above ground level directly against
the front short metal wall (exterior side) of the hangar directly above the
door opening.  The hangar is of corrigated steel construction and the receiver
is protected by the metal roof overhang about 2 ft. above.  Originally this
worked O.K. except that the range was marginal.  Lately, I find the range to be
decreasing to the point that the system is unusable, even with a fresh battery
in the transmitter.  The point in all this rambling is to solicit ideas for
improving the range.  I looked inside the transmitter today with a mind to look
for the transmitting antenna in hopes of attaching an aux whip or something. 
What I see is a several turn wire coil and I assume that any modification of
this would probably require a re-tuning that is beyond by capability.  Any
thoughts of placement of the receiver?  Should I try to move it out from the
metal wall? Insulate between the wall and the receiver?  Try to adapt an
additional antenna for the receiver (its just a plastic box with no external
antenna)?  The remote actually works through the metal wall (i.e. the
transmitter inside the receiver mounted on the outside metal wall with no
line-of-sight between)--Does the receiver perhaps utilize the 110V lines
inside as an antenna?   Does a better alternative remote exist for not too many
dollars?

There, now that I've exposed my total ignorance can someone suggest some help?

Dudley McMackins              demcma@bb1t.monsanto.com
Newsgroups: sci.electronics
From: strong@tc.fluke.COM (Norm Strong)
Subject: Free Parts!
Organization: John Fluke Mfg. Co., Inc., Everett, WA
Date: Thu, 13 Aug 1992 18:05:24 GMT

I have mailed out resistor sets to all those who asked for them (and
sent me an address.)  If you don't get yours, let me know.  I'll be on
vacation until 8/21.  


-- 

Norm Strong  (strong@tc.fluke.com)
2528 31st S.   Seattle WA 98144   USA
Newsgroups: sci.electronics
From: billq@ms.uky.edu (Billy Quinn)
Subject: Composite to RF converter (Video) ??
Keywords: video,RF
Date: Tue, 18 Aug 1992 15:29:33 GMT
Organization: University Of Kentucky, Dept. of Math Sciences

I have been trying to find a device that will convert composite video into
an RF modulated video signal (channel 3 or 4).  I remember seeing them used
with CGA cards.  I might have just over looked the things in my catalogs etc.
I would rather avoid any hacking that might leave my working composite signal 
unusable.

Do any of you know where I might be able to buy such a device, and if so -
how much will it cost me?


Thanks for any suggestions!


-- 
*-----------------------------------------------------------------------*
*	Bill Quinn			billq@ms.uky.edu		*
*-----------------------------------------------------------------------*
Newsgroups: sci.electronics