HDTenEightyP/NetNews huggingface dataset:
From: hbg6@phx.mcd.mot.com (John Schuch)
Newsgroups: sci.electronics
Subject: Re: 7 seg. Hex display driver IC?
Date: 27 Jul 92 20:22:32 GMT
Distribution: na
Organization: Motorola Computer Group, Tempe, Az.

In article <55066@mentor.cc.purdue.edu> falatic@mentor.cc.purdue.edu (MacGyver) writes:
>	Hi! I am looking for a chip to convert BCD (actually, straight 4 bit 
>binary) to drive a 7 segment LED display, and to display 10d to 15d in
>Hexadecimal (A-F). I need something LIKE a 7447 driver, but that one does not 
>treat 10d-15d the way I need. Anyone who can help, please reply thru E-Mail
>if possible, or post here.


How's your budget? :-)    The IDEAL part is the HTIL311 display from
Texas Instruments. Inside the packeage are: a four bit latch (tristate),
BCD to display converter, LED drivers, and a 5 X 7 matrix of LEDs.
Apply BCD data to the input pins, pulse the DV ( data valid ) pin, and
presto,  hex code shows up on the display.

I'm using these in a DTMF project I'm working on. Unfortunatly the
last time I dared to ask they cost about $13 each, but still a cool part.

John


------------------------------------------------------------------------
John Schuch              hbg6@phx.mcd.mot.com              (602)438-3008
Motorola Computer Group - Technical Systems Division - Manufacturing Eng
------------------------------------------------------------------------
   People who wear ties to insure a 'good' first impression realize
 that they have no hope of correcting an impression at later meetings.
------------------------------------------------------------------------
From: johnh@macadammq.edu.au (John Haddy)
Newsgroups: sci.electronics
Subject: Re: Solder Mask Repairs
Date: 29 Jul 92 23:05:21 GMT
Organization: Macquarie University, School of Mathematics, Physics, Computing and Electronics

In article <9207290420.AA12381@worf>, dlou@ECE.UCSD.EDU (Dennis Lou) writes:
|> 
|> I had a PC board that was heavily corroded.  I managed to scrape away
|> most of the corrosion, but I also managed to scrape away some of the
|> green solder mask in the process.
|> 
|> Can I use a resist pen to repair the solder mask or do I need to waste
|> money on a spray that I don't have?  The area is quite small (less
|> than a square cm) and I don't want to buy a can of something that I'm
|> going to use once and throw away.
|> 
|> --
|> Dennis Lou             || "But Yossarian, what if everyone thought that way?"
|> dlou@ucsd.edu          || "Then I'd be crazy to think any other way!"
|> [backbone]!ucsd!dlou   |+====================================================
|> dlou@ucsd.BITNET       |Steve Jobs and Steve Wozniak went to my high school.

Unless you live in an area with high humidity, you'll get away without needing to
repair it. (I'm assuming that you've just fixed an already loaded board i.e. that
doesn't need wave soldering.) If you _really_ want to put something else in the
solder mask's place, use anything that i) insulates (obviously) and ii) protects
against moisture. A smear of silicone sealant would work over that size area, so
would a dab of household furniture or floor varnish.

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

      |  _  |_   _   |_|  _   _|  _|              Electronics Department
    |_| (_) | | | |  | | (_| (_| (_| \/           School of MPCE
    ---------------------------------/-           Macquarie University
                                                  Sydney, AUSTRALIA 2109

    Email: johnh@mpce.mq.edu.au, Ph: +61 2 805 8959, Fax: +61 2 805 8983

----------------------------------------------------------------------------
Newsgroups: sci.electronics
From: tchannon@black.demon.co.uk (Tim Channon)
Subject: Gerber previewers / converters 
Distribution: world
Organization: null
Date: Mon, 20 Jul 1992 01:58:41 +0000

> Has anyone met any (preferably free) software to preview Gerber
> photoplot files or convert Gerber to other graphics formats?
> 
No problem. There is a good shareware program for the ibm compat.

GC-PREVUE

GraphiCode 

19101 36th Avenue West, Suite 204
Lynnwood WA 98036
USA

tech support (206) 771 5600
  BBS        (206) 771 6980
  sales      (206) 672 1980
  fax        (206) 692 2705     

ftp from pdsoft.lancs.ac.uk and no doubt elsewhere ideas anyone?

pdsoft  is  changing  it's  name and finding things is interesting unless you 
have the index. Very good if you do have index -- every file set has it's own 
subdirectory and a plain english description file in that  directory,  others 
please copy.

  TC. 
    E-mail: tchannon@black.demon.co.uk or tchannon@cix.compulink.co.uk
From: hoven@etek.chalmers.se (Hans-Ove Frimodig)
Newsgroups: sci.electronics
Subject: Re: White noise generator.....
Date: 28 Jul 92 09:49:28 GMT
Organization: Chalmers University of Technology, Gothenburg, Sweden

Why not find a small FM radio without muting or the ability to switch
it off. Then you just tune it so it doesn't receive a station.
It may be easier to do this if you disconnect the antenna.

/Hans-Ove Frimodig
hoven@cd.chalmers.se
From: cs00jmc@unccvax.uncc.edu (John Covington WN4BBJ)
Newsgroups: sci.electronics
Subject: NC/SC HAMFEST INFO MAILING LIST ANNOUNCEMENT
Date: 24 Jul 1992 13:17:13 -0500
Organization: UTexas Mail-to-News Gateway
NNTP-Posting-Host: cs.utexas.edu

(I don't think this got through, so I'll try again)

         NC/SC HAMFEST INFO MAILING LIST ANNOUNCEMENT

I have been maintaining an electronic mailing list for the last year and 
a half, and thought that there might be a few people on the net that 
would like to know about it.  I posted an announcement a year ago but
a lot of new people are on the net so I thought I would post another
announcement.

This list describes hamfests in North and South Carolina, and is updated
as needed, usually about once a month.  I have included a few hamfests
outside of the Carolinas that may be of interest.

The list has a calendar of hamfest dates and locations for the
rest of the year; and a few paragraphs about each hamfest that
will take place during the next month.   I try to include 
info about the hamfest location, whether exams are offerred,
ticket pricing, "more info" addresses, and sometimes brief remarks
about the hamfest based on my personal experience.

I developed this list to answer e-mail questions I received from
people ("Are there any hamfests in this area in the near future?"),
especially non-hams who often don't hear about the hamfests otherwise.
However, there are hams who read it as well, since I try to combine 
information from multiple sources into a simple, quickly read message.

I have been posting this information to the triangle.radio newsgroup
for the last 2 months, but I can't guarantee that I will be able to
do that after the end of the year.  I don't post it to rec.radio.amateur.misc
or other national/international groups on a regular basis
since the information is only useful to a small part of the country,
and due to the flamage that might result.

So if you need hamfest information for North and South Carolina
and would like to be put on the e-mail list,  contact me at 
cs00jmc@unccvax.uncc.edu or 3426957@mcimail.com
and I will add you to the list!

Xref: sparky sci.electronics:13423 sci.physics:11773
Organization: Middle East Technical University - Computer Center
Date: Monday, 27 Jul 1992 12:11:09 TUR
From: <C44590@TRMETU.BITNET>
Newsgroups: sci.electronics,sci.physics
Subject: help on ref.for scattering

scattering of electromagnetic waves by different cross sectional cylinders
with complex permitivity is the topic of my M.Sc.thesis, i do need as more
possible as references on this topic.any help will be appericiate

thanks in advance
Newsgroups: sci.electronics
From: rn11195@sage (Robert Nehls)
Subject: Unknown RAM
Organization: Medtronic, Inc.
X-Newsreader: Tin 1.1 PL4
Date: Tue, 28 Jul 1992 21:04:58 GMT

I've got a RAM (8K X 8) which only has F134RA marked on it.  I haven't been
able to find it in any data books.  Any help in identifying it would be
appreciated.  Thanks in advance.

Bob Nehls

Newsgroups: sci.electronics
From: billq@ms.uky.edu (Billy Quinn)
Subject: Telmos 1852 Video DAC ???
Keywords: video,telmos,DAC
Date: Mon, 27 Jul 1992 16:59:20 GMT
Organization: University Of Kentucky, Dept. of Math Sciences

I have a 1987 refference to a Telmos 1852 video DAC.  It looks like a really
simple chip to use for interfacing to composite video out put.  I need to
find out the following:

1) What is a telphone number for Telmos?
2) Who distrubutes them (Future, Arrow, etc?.) ?
3) Is this chip still manufactured?
4) How much does it cost?

I need to generate a B&W video signal to drive a TV set. My signal will be a
VLF wave form (that is my image will be a VLF wave form on the TV).  Any tips
on a cheap way to do this with a MCU/MPU and a few other chips?

Thanks,

-- 
*-----------------------------------------------------------------------*
*	Bill Quinn			billq@ms.uky.edu		*
*-----------------------------------------------------------------------*
Newsgroups: sci.electronics
From: medin@catbyte.NoSubdomain.NoDomain (Dave Medin)
Subject: Re: 20W Audio amplifier chip TDA1520
Reply-To: medin@catbyte.b30.ingr.com
Organization: Intergraph Corporation, Huntsville AL
Distribution: usa
Date: Fri, 31 Jul 1992 18:55:56 GMT

In article <64674@hydra.gatech.EDU>, gt8021a@prism.gatech.EDU (EASON) writes:
|> Thanks to all who responded to my questions about the Philips/Signetics
|> TDA1520 audio amplifier chip: Matthew Kleinmann, Dave Medin, Arun Rao, Chris
|> Richmond, K. C. Lee, and Dzung T. Hoang.  I got one channel working last
|> night (about 12am!).
|> 
|> For those who are interested, the TDA1520 is a mono "20W Hi-Fi Audio Amplifier"
|> chip that Radio Shack used to sell.  I bought two on closeout there at least
|> two years ago.  Dave Medin reports that Signetics still makes the chip, and
|> it's available from Digi-Key (price?).  It's about 1"x1/2", 9-pin SIP.
                                 ^^^^^^^
                                $6.71  (1-800-DIGIKEY)

|> The chip has internal thermal protection circuitry, but it needs a heat sink 
|> for normal operation.  I bought a big one with two sets of fins and sawed it
|> in half.  Again, Dzung Hoang's voice of experience came in handy in telling
|> me not to mount both chips (two for stereo) on the same heatsink.  Doing
|> this lets the smoke out, and they won't work any more.

Well, actually try insulating the package from the heatsink with the
standard mica washer and grease, and two channels on the same heat sink
will work fine. The 9 pin SIP package allows the use of a washer designed
for TO-3 transistors, which are readily available. I'd suggest electrically
isolating the device from the heatsink anyway and leaving the
heatsink floating. It is less likely that you'll destroy anything
if you accidentally hit the heatsink with a loose lead while
experimenting and thus "let the smoke out."

-- 
 --------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    Intergraph Corp.				(205) 837-1174 (h)
       M/S GD3004
  Huntsville, AL 35894 		Internet: medin@catbyte.b30.ingr.com
				UUCP:  ...uunet!ingr!b30!catbyte!medin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)
Xref: sparky sci.electronics:13332 alt.folklore.urban:19806
From: smb@ulysses.att.com (Steven Bellovin)
Newsgroups: sci.electronics,alt.folklore.urban
Subject: Re: SHOCKING STORIES
Date: 26 Jul 92 03:17:47 GMT

In article <1992Jul25.030622.897@engage.pko.dec.com>, moroney@ramblr.enet.dec.com writes:
> Largest voltage?  Probably one winter when I scuffed my feet across the
> rug or pet the cat vigorously and touched the doorknob or something...
> Thousands of volts but no current.

With this as an intro, we can all tell our favorite Tesla coil stories.
(Or Tesla stories -- the man was a walking urban legend generator.)
Newsgroups: sci.electronics
From: jim@rwsys.lonestar.org (James T. Wyatt)
Subject: Re: Microcontrollers
Organization: R/W Systems, Richland Hills, Texas, USA, 76118-5849
Date: Tue, 28 Jul 1992 04:50:49 GMT
Summary: Dallas Semiconductor DS5000 is good for tinkering/development
Keywords: DS5000 8051 hacking microcontroller BASIC FORTH

In article <BrMFKp.L8@world.std.com> jonas@world.std.com (Jonas R Klein) writes:
>I'm a mere hobbyist who is looking for a one-chip microcontroller
>for various applications.  The mind-boggling assortment of various
>types has me stymied, though.  I'm looking for low cost, built in
>UART, small size (28 pin?).  Or if there are ones that use 68000
>code, programming would be easier as I have Amiga C compilers.
>Any help would be appreciated.

If you are looking for a good starter microcontroller, try the
Dallas Semiconductor.  Why?  Because:
  1) It doesn't need a programmer. You just power it up in 'load' mode and
	shove hex down the serial port. A built-in lithium battery holds
	your code for years. No delay while programming/erasing and no
	limit on number of reprogram cycles. You can write (or port) a
	monitor or FORTH or BASIC interpreter since it has lots of RAM.
  2) It has pleanty of ROM/RAM (8-64Kb, depending on cost), an on-board
	(autobaudable to 9600) serial port, timers, counters, and lots
	of programmable I/O digital lines.
  3) It fits in a 40 pin socket or a 40 pin SIMM (DIP only is 8 or 32Kb,
	but SIMMs come in 8/32/64Kb flavors). Sorry no 28-pin version.
  4) There is free software from Intel (assembler, loader). The
	Frankenstein assemblers in the UseNet archives support it too.
  5) It's pin (electrical) and 	bit (binary code) compatable with the
	Intel 8051, so if you build something you can put it into a
	cheaper part w/ EPROM and keep your DS5000 for the next project.
  6) It is very low power, if you want to power with batteries.
  7) If you build something like an encoder box, you can encrypt the
	firmware to prevent reverse-engineering.

Disadvantage:	It is an older 8-bit architecture and thus limited
	in its addressing and and programming. It also uses Intel's
	odd memory layout - but you get used to it. The SIMM is
	difficult to get a wire-wrap socket for. For the Amiga, you
	would have to get/compile the Frankenstein assemblers, I think.

addendum: Most of the software noted above works under MSDOS. The
	Frankenstein assemblers work on anything w/ a compiler. A
	FORTH or BASIC or monitor program would work on the DS5000.

-- 
James Wyatt  KA5VJL  jim@rwsys.lonestar.org  Semper Gumbi - always flexible!
From: amigo@milton.u.washington.edu (The Friend)
Newsgroups: sci.electronics
Subject: dip-based amplifiers
Date: 24 Jul 92 06:15:19 GMT
Article-I.D.: milton.amigo.711958519
Organization: University of Washington


	What are some of the numbers for a few higher powered DIP-based
power amplifiers? I'm looking for >20 watt versions.



					Thanks,
					Mike
Xref: sparky sci.electronics:13069 alt.folklore.urban:19352
From: jeremiah@yang.earlham.edu (Jeremiah Wilton)
Newsgroups: sci.electronics,alt.folklore.urban
Subject: Re: SHOCKING STORIES
Date: 21 Jul 92 14:05:58 GMT
Organization: Earlham College, Richmond, Indiana

>>In article <1992Jul18.175339.10396@newstand.syr.edu>,
>>	feliccia@rodan.acs.syr.edu (Nicholas J Feliccia) writes:
>>
>> Ok. I want to know from the net people. What is the largest voltage shock
>> you have ever received (and survived.) I am not talking about rewiring
>> a light switch. I am talking about kissing the flyback transformer.

When I was in eighth grade I used to play with electricity a lot with my 
friend, Nathaniel.  Nathaniel got the idea that it would be funny to take 
his Variac transformer, turn it down to zero, clip the two leads to his 
braces (one on the top, one on the bottom), and slowly increase the voltage.

At 50 volts, he was still saying, "nothing yet..."  the conductance 
threshold ended up being about 52 volts.  Fortunately, he lived, and was 
still able to eat through a straw.
-- 
Jeremiah Wilton | jeremiah@yang.earlham.edu | JEREMIAH@EARLHAM.bitnet |
"Chen2 Qi2"     |       NeXTmail only: jeremiah@math.earlham.edu      |
From: gtolar@xcluud.sccsi.com (Glynne Tolar)
Newsgroups: sci.electronics
Subject: Re: Caller ID
Date: 21 Jul 92 06:24:24 GMT
Distribution: na
Organization: Greater Montrose UFO Appreciation Society & Data Haven

In article <1992Jul20.010251.22840@kcwc.com> curt@kcwc.com (Curt Welch) writes:
>In sci.electronics, ferguson@andy.bgsu.edu (Douglas Ferguson) writes:
>>The *ideal* solution -- and one the phone company is reluctant to
>>offer because they can't get RICH off of it -- is to have CALL TRACE,
>>an existing technology whereby ...
>
>I'm not sure what you're saying here, but in cause some people
>don't know it, this feature is offered by C&P.  Anyone can use it
>and there's no charge.  You type a * code (I forget actual code -
>it's in the phone book) and the number of the last person that
>called you is saved so that it can be given to the police - the
>customer never sees it.
>
>Curt

We have that service in SE Texas and leave it to Southwestern Bell and our
Public Utilities Comission, we pay $1/month for the service (no install
fee, believe it or not) and $8 for each sucessful call trace used.  Nice
guys!

-- 
-----
gtolar@xcluud.sccsi.com or uunet!nuchat!xcluud!gtolar
Newsgroups: sci.electronics
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Underground CD copying
Date: Wed, 22 Jul 1992 17:06:59 GMT
Organization: U of Toronto Zoology

In article <klp.711752974@reg> klp@doe.carleton.ca (Ka Lun Pang) writes:
>I don't know the details of making a CD but as I understood, there are 
>micro hills and valleys representing 1's and 0's. Now if the bad guys have
>the technology of manufacturing CD, which part(s) of the process they can't
>do perfectly to cause degradation in fidelity?

The obvious possibility is that their source material is second-rate, and
the CD pressing is just faithfully reproducing the source's limitations.
If you make a CD from a cassette tape made on a pocket recorder, what you
get is pocket-recorder fidelity.

CD reproduction is done by a pressing process, literally:  the CD blank
is pressed against a metal master which has bumps where the CD is to have
pits.  Conceivably, a sloppy job on this could result in second-rate CDs.
-- 
There is nothing wrong with making      | Henry Spencer @ U of Toronto Zoology
mistakes, but... make *new* ones. -D.Sim|  henry@zoo.toronto.edu  utzoo!henry
Newsgroups: sci.electronics,comp.sys.ibm.pc.hardware
From: polish@cs.columbia.edu (Nathaniel Polish)
Subject: Re: Airport X-Rays
Organization: Columbia University Department of Computer Science
Date: Mon, 27 Jul 1992 14:53:21 GMT

I think we should clarify the model for how an airport x-ray damages
a magnetic medium.  Certainly large fields will degauss a floppy but this
is unlikely except as noted from the motors.  The real problem with x-rays
is that they are high-energy radiation.  They can cause small ionizations
on the surface of the disk.  If the ionizations are small relative to the 
size of the magnetic domains, then there is no visable problem.  As the 
media get denser, the domains get smaller and the problems appear.  However,
modern airport x-ray equipment is very sensative and they use very weak 
sources -- mostly to protect the workers.
From: ralph@falcon.SLAC.Stanford.EDU (Ralph Becker-Szendy)
Newsgroups: sci.electronics
Subject: Re: Airport X-Rays
Date: 24 Jul 92 22:55:44 GMT
Organization: Stanford Linear Accelerator Center

In article <22754@oasys.dt.navy.mil> dlee@oasys.dt.navy.mil (David Lee) writes:
>I think it would be smart to avoid any magnetic fields, either generated
>by permament magnets or electromagnets,.i.e. motors,..etc.  Data on
>floppy or hard disk is of a magnetic nature; and any magnetic field
>can, erase if strong enough, or distort so that the pc cannot recover
>the data.. PC users have been cautioned constantly about leaving floppy
>disk by telephones and on top of monitors.. It might not happen, but it
>could.. So, why take the risk??? It's amazing where you can find magnetic
>fields in an office or home environment!!!

Good idea. First step is to avoid the earth. Around the countryside,
the greatest danger is from the earth's magnetic field (which is
around 1/3 gauss, if my memory serves me right). So off to space we go
(I knew there was a good reason to build the space station) :-) If you
want to be extra-careful, please remember that the planet Jupiter has
a substantial magnetic field (strong enough to be measureable on
earth, which measurement for a while set the best limit on the mass of
the photon, by the way).

Now serious. Could someone present some more quantitative information
about what strength of magnetic field it takes to damage a floppy of a
certain density (8" SSSD will probably react very different from a ED
4MB 3.5" floppy)? How about tapes ? I have successfully bulk-erased
6250 bpi 9-track tapes, but I hear that 8mm tapes are just about
impossible to bulk-erase. What magnetic field does it take? Facts
please; not urban legends or generic warnings.

And while we are asking for facts (which are a rare find on this
newsgroup): How about EPROMs and similar stored-charge memory devices?
After all, EPROMs are erased by UV, do they resist the airport X-ray
machine? I'd guess that the X-rays are heavily attenuated by the case
of the EPROM (the top of which is transparent to UV light but not to
X-rays), but is there real danger to EPROMs ?

-- 
Ralph Becker-Szendy                          RALPH@SLACVM.SLAC.STANFORD.EDU
Stanford Linear Accelerator Center                      RALPH@SLACVM.BITNET
M.S. 95, P.O. Box 4349, Stanford, CA 94309                    (415)926-2701
My opinion. This is not SLAC, Stanford U, or the US DoE speaking. Just me.
Xref: sparky sci.electronics:13456 rec.audio:10935 alt.folklore.computers:11278
From: smee@bristol.ac.uk (Paul Smee)
Newsgroups: sci.electronics,rec.audio,alt.folklore.computers
Subject: Re: Life after CDs
Date: 28 Jul 92 13:26:35 GMT
Reply-To: P.Smee@bristol.ac.uk (Paul Smee)
Organization: University of Bristol

In article <1992Jul27.092328.21478@discus.technion.ac.il> sorin@techunix.technion.ac.il (Goldenberg Sorin) writes:
>Somehow the cd manufacturers seem to squeeze more music into the c.d.
>I have Mahler 2.nd with Klemperer - above 79 min.

CD specs are all given as notional figures with tolerance ranges.  E.g.
the track separation is X plus-or-minus Y, rotational speed is X
plus-or-minus Y, and so on.  If you accurately hit all of the X's, then
the resulting CD contains 74 (approx) minutes of music.

However, if your manufacturing equipment and process methods are accurate
enough to allow you to press right at the (correct) edge of the
tolerance ranges, you can get more music on (up to 80 some minutes, I
believe).  Problems are that then you've got to be spot-on accurate,
because you've left no safety margin; and that some players,
particularly older and cheaper ones, can't handle disks which are
pressing right up against all the tolerance limits simultaneously.  (And,
some disk makers put a line on the front cover along lines of 'warning,
this disk contains more than X minutes of music' -- though they don't
normally bother to explain why you might care.)

It's been a while, but I believe that the official spec for CDs does
specifically permit manufacturers to push the limits in this way,
providing that they use more stringent quality control methods to
ensure that they don't overstep any of the tolerance boundaries.

-- 
Paul Smee, Computing Service, University of Bristol, Bristol BS8 1UD, UK
 P.Smee@bristol.ac.uk - ..!uunet!uknet!bsmail!p.smee - Tel +44 272 303132
Newsgroups: sci.electronics,rec.audio