HDTenEightyP/NetNews huggingface dataset:
From: butts#@shocker.ee.twsu.edu (Ronald W. Butts -SUPER ACCT)
Subject: re: A PSPICE question
Organization: Electrical Engr. Dept, Wichita State Univ.
Keywords: PSPICE,SPICE
Date: Sat, 26 Sep 1992 06:38:52 GMT
X-Posted-From: gegan1.ee.twsu.edu
NNTP-Posting-Host: sol.ctr.columbia.edu

Hi,

Transient analysis is not the best way to apporach the problem. If you
sweep the frequency very slowly at all, you will have to simulate for a large
number of points to catch the features of the waveforms for the whole time
period. You will easily exceed the maximum points limit on PSPICE (and PROBE).

The information (I suppose) you are after- the shape of the envelope, is
more easily determined from a .AC frequency-domain analysis. You can see
the amplitude of the sinusoid (VM(n)) as a function of frequency, which in
your case is in turn related to time.

If you are sure you want a transient analysis, you can easily generate a
source of almost any function using the "Analog Behavior Modelling" option
of the production P$PICE, which is also (quietly) included in the student
version.

Using the ABM, you can use the VCVS (Exxxx) and VCCS (Gxxxx) devices and
give them a value that is a function of any voltage, current, or "time".

For your case, to sweep freq from 1KHZ to 100KHZ in one second, I used the
following program on a simple R-L circuit/

e1 1 0 value={sin(2*3.14159*(1000+99000*time/1)*time)}
l1 1 2 1
r1 2 0 10k
.tran    10.000u  1        0         ; *ipsp*

The program bombed (too many points) after a small fraction of the run...

The capability to use "value={expression}" is very powerful. Makes generating
all those weird polynomial text-book examples into child's play.

It also has the capability to use "LAPLACE={function of 's' and signals}" 
to give an output as a laplace transfer function. I suppose it uses
inverse FFT and convolution for the transient solution... ?

If your place has a professional version with the ABM documentation, read it.

The student version is quite a powerful program for the money. Microsim
is quite generous, I feel.

Bill Butts
Wichita State University
EE Dept.
butts@shocker.ee.twsu.edu
From: cgordon@vpnet.chi.il.us (gordon hlavenka)
Newsgroups: sci.electronics
Subject: Re: 8051 multitasking kernel, comments please
Keywords: 8051 real-time multitasking kernel
Date: 4 Oct 92 04:37:45 GMT
Organization: Vpnet Public Access


 bomr@erich.triumf.ca (Rod Nussbaumer) writes:
>I am in the market for a real-time kernel to be used in 8051 family
>projects.  I have contacted a number of vendors, and am waiting for
>their literature packets and demos.  I am wondering if anyone can
>comment on any of their experience with these products, or knows of
>other products to explore.

_Embedded Systems_ magazine just finished a series wherein they
described the full inner workings of a freeware realtime kernel called
"UCOS."  The series started in the June 1992 issue.

UCOS is implemented on the 80188, but full source is provided and it
should be portable to other architectures.  You can get UCOS from the
Embedded Systems BBS at 1 (415) 905-2689 or in library 12 of CLMFORUM
on CI$.

-- 
----------------------------------------------------
Gordon S. Hlavenka           cgordon@vpnet.chi.il.us
  Don't forget:  Dave Barry/Joe Walsh in November!
Newsgroups: sci.electronics
Subject: Re: PSPICE Part ".MODEL" FTP SITES? Where?
From: sldf3@pluto.ee.usu.edu (beal weston r)
Date: 28 Sep 92 10:57:19 MDT
Distribution: world
Organization: Utah State Univ. EE

In article <1a14bfINNdtg@usenet.INS.CWRU.Edu>, bh725@cleveland.Freenet.Edu (Werner J. Karl) writes:
|> 
|> Are there any FTP Servers out on the Net that have such kind
|> of things for PSPICE ??
|> Thanx previously,Werner

-- 

The University of Utah has a pretty good stash of pspice models.
try ftp to ee.utah.edu.  I'm not 100% sure about that node name.


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%  Weston Beal			:  I have a piece of hard rock      %%
%%  sldf3@sol.ee.usu.edu	:  candy, but it's not for eating.  %%
%%  sldf3@cc.usu.edu		:  It's for looking through.        %%
%%                                                                  %%
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From: dcb0@gte.com (Daniel Bazinet)
Newsgroups: sci.electronics
Subject: Re: 8051-->8259 PIC
Keywords: 8051 interrupt 8259
Date: 1 Oct 92 14:26:31 GMT
Distribution: na
Organization: GTE Laboratories Incorporated, Waltham MA


	In response to the person asking about the 8259 interrupt
	controller .....  
	  I don't know much about the 8051 except that it's popular
	as hell right now.  
	  Yes, if the 8051 is capable of accepting interrupt signals
	and has the ability to vector a particular interrupt to a 
	specific service routine, the 8259 is the chip to use.
	  Since the 8051 is an Intel micro, I would assume that if it
	has interrupt pins you're all set.  Do not use the Zilog PIO
	chip as someone else suggested, ... it does have interrupt
	generation capability, but works completely differently.  With
	this chip, when it pulls the interrupt line, the Z80 series CPU
	expects the PIO to put the address of the interrupt routine
	on the address bus ... the CPU then picks up operation at that
	address.  The PIO can also only service one or two different
	interrupts per PIO chip while the 8259 can handle 9 different
	ones if memory serves me correctly .....

					Good Luck,
					   Dan Bazinet
					dcb0@bunny.gte.com
Newsgroups: sci.electronics,comp.robotics
From: martinez@rodan.acs.syr.edu (Kenneth Mtz. (YONIX))
Subject: D.C. Motors for micromouse
Originator: martinez@rodan.acs.syr.edu
Organization: Syracuse University, Syracuse, NY
Date: Fri, 2 Oct 92 19:46:47 EDT


  We are trying to decide what type of motors to use to drive
the micromouse we will be designing for our senior project.
Anyone out there who could give us some hints on which devices
to choose from, a bit about how they operate? In general, any
tips on the subject would be very helpful.

	Please reply to this account, I will post a summary if people
are interested.

Thank you in advance,

Kenn
From: whit@milton.u.washington.edu (John Whitmore)
Newsgroups: sci.electronics
Subject: Re: Grounded soldering iron tip
Date: 5 Oct 92 22:38:44 GMT
Article-I.D.: u.1992Oct5.223844.14103
Organization: University of Washington, Seattle

In article <1992Oct5.034325.2108@athena.cs.uga.edu> mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:

>How important is it to have the tip of a soldering iron be grounded
>(as opposed to simply disconnected from everything)?

>I use a small grounded-tip iron most of the time, but I have a larger
>one, occasionally used for desoldering, which is not grounded-tip.


        If by 'disconnected from everything' you mean the tip
is on a battery-powered soldering iron, it might be OK.  The
stray capacitance of a battery-type iron is low, and there will
be significant limiting resistance in the tip.

        If you mean 'not directly connected to 110VAC', it might
NOT be OK.  Insulators are not reliable at elevated temperatures,
and stories abound of folk soldering on live circuits with
standard irons, and finding an accidental 110V excitation
that permanently releases the magic smoke from their expensive
equipment.  It will also fry MOS, but that doesn't look as
spectacular (it happens, though, with mere megohms of leakage
resistance: only with transformer-type irons can you be assured
that the leakage resistance is truly high).

        If you really care, unplug the ungrounded iron before using
it (and touch the tip to ground before it contacts the circuit).
Grounded-tip irons are more reliable than this sort of 'technique'.

        John Whitmore
Newsgroups: sci.electronics
From: jeremym@fraser.sfu.ca (Jeremy Thomas McDonald)
Subject: noise when interfacing TTL&CMOS?
Organization: Simon Fraser University, Burnaby, B.C., Canada
Date: Sat, 3 Oct 1992 07:04:38 GMT

Is there any PC-Board noise generated when interfacing CMOS outputs to
TTL inputs?  How about TTL to HCT?  Is CMOS to HCT less noisy than
CMOS to TTL?  I have a spec for a CMOS ADC chip that states, for less
noise, only connect outputs (of the ADC) to CMOS inputs, yet I need
some way of connecting some control signals of the CMOS part to TTL inputs.
Noise is a critical factor, as I am hoping to get 16-bit sampling.

Newsgroups: sci.electronics
From: wrb@cbnews.cb.att.com (wallace.r.blackburn)
Subject: Re: Need 16450 for serial port.
Organization: AT&T
Distribution: usa
Date: Thu, 1 Oct 1992 13:15:45 GMT

In article <92275.002602ZHAO@auvm.american.edu> <ZHAO@auvm.american.edu> writes:
>Does anyone know where I can find a 16450 for serial port. My 386 needs
>another port. Maybe soneone has abandent I/O cards and willing to sell
>for $$$.  Please E-mail to me.
>

*IF* you have a system (or software package?) that can take advantage of it,
the 16550 is a better choice.  The 16550 has 16-byte FIFOs that can buffer
the data coming in.  If you have a real OS, like OS/2, you can set the port
for buffering and your system then only has to respond to an interrupt for
every 14 or so characters - instead of every character.  This really pays
off with high speed (9600 and up) modems.

Probably no advantage with DOS or Windoze, however.  I could be wrong - I'm
sure the net.vicious.psychos will let me know!  Direct all flames to
/dev/eatme.  Gosh, I'm in a nasty mood today. ;)

Oh yeah, JDR has the 16450 for $10.95 - 1-800-538-5000.  Active has a 16550
clone (by TI) - the TL16C55A for $9.95 - 1-800-932-7769.  Active may have
the 16450 cheaper too (I would think so if they have the 16550 for less
that the 16450 at JDR).  I don't have a catalog.  Even if you can't take
advantage of the 16550, I don't think it will hurt so it is a better deal
anyway.


			Wally Blackburn AA8DX
From: Joseph.Wetstein@mailbox.bison.mb.ca (Joseph Wetstein)
Newsgroups: sci.electronics
Subject: multimeters
Date: 24 Sep 92 20:26:10 CST

Organization: Drexel University, Philadelphia PA

I would like to buy a good multimeter. Ya know, measures voltage,
current, resistance (the good ones measure capacitance).

If anyone has any suggested brands either to or not to buy, and places
either to or not to buy from, I would really appreciate hearing from
you.

jpw@coe.drexel.edu  (e-mail preferred)

 * Origin: The Electronic Mailbox (1:348/7.0)

Newsgroups: sci.electronics
From: article@fluke.tc.fluke.com (John F. Berkey)
Subject: Re: Multimeters
Organization: John Fluke Mfg. Co., Inc., Everett, WA
Date: Fri, 2 Oct 1992 19:36:04 GMT

In article <1992Sep25.204230.15040@bernina.ethz.ch>, schaerer@isibee (Thomas
Schaerer) writes:

> Very easy to find out this address because we have many of FLUKE-devices.
> 
> 	USA:	John Fluke MFG. CO., INC
> 		P.O. Box 43210
> 		Mountlake Terrace, Washington 98043
> 

Contact: USA:  John Fluke Mfg. Co., Inc.
               2375 130th NE, Suite 100 
               Bellevue, Wa 98005-1758

Phone:         (206) 881-6966
Fax:           (206) 885-6310

For immediate assistance call: 1-800-44-FLUKE

Our customer assistance people will be happy to answer your questions.

-- 
______________________________________________________________

John F Berkey
Chief Quality Specialist
John Fluke Mfg, Co., Inc.
C.M.M. Dimensional Inspection,
Service Tools Organization

article@tc.fluke.com

Disclaimer: All views and opinions stated here are my own, 
            and in no way represent the views of my employer.
From: tomb@hplsla.hp.com (Tom Bruhns)
Newsgroups: sci.electronics
Subject: Re: Which Diode?
Date: 28 Sep 92 23:47:24 GMT
Article-I.D.: hplsla.5170226
Organization: HP Lake Stevens, WA

gallant@oasys.dt.navy.mil (Robert Gallant) writes:

>Hi, I am trying to find the proper diode to combine the trigger signals
>from two ignition coils on my car.

(Diagram of std coils and diodes and description deleted)

>The voltage present at the (-) terminals should be alternating between
>0 and +14.1 volts at 300 Hz maximum.

Heh, heh, heh.  What makes you think _that_??  The turns ratio on an
ignition coil would never get you enough to put a spark across a plug
if the ratio was simply applied to 13 or 14 volts.  Nope.  The system
works by storing energy in a magnetic field in the coils, and letting
that field collapse very quickly when the points open.  When the field
collapses, the primary voltage as well as the secondary voltage goes
up a lot:  the (-) terminal can reach 300 to 400 volts -- even more
if the capacitor is too low a value.  Basically, the capacitor forms
a resonant circuit with the primary of the coil, and energy gets put
in when the points are closed.

Anyway, if you really want to do this, you could use fast, high-voltage
diodes, then be ready to accept the resulting rather high voltage
output at the diode junction, or you could put some other resonable
trigger circuit on it.  An inductive pickup is possible (on the spark
wire, like timing lights use), as is a _resistor_ from each coil to
a resistor to ground (forming a two input voltage divider), with clamp
diodes to keep the output under control.  If you use resistors, use
high enough values to not damp the coil too much:  I'd start with
something like 100kohm, 1 watt units, into about 250 ohms/volt of
desired output.  Be aware that each firing pulse may consist of several
cycles of a fairly high frequency...don't let that fool your logic.
Newsgroups: sci.electronics
From: rainer@spot.Colorado.EDU (Rainer Malzbender)
Subject: Re: multimeters
Organization: University of Colorado, Boulder
Distribution: na
Date: Mon, 28 Sep 1992 03:45:51 GMT


I got an incredible deal on a high end Fluke handheld, the 8060A, and it's
just wonderful.

-- 
Rainer Malzbender
Post-doc, Physics
U. of Colorado, Boulder (303)492-1366           rainer@boulder.colorado.edu
Newsgroups: sci.electronics
From: sehari@iastate.edu (Babak Sehari)
Subject: Re: Opening other people's Garage doors : )
Originator: sehari@lisa.ecss.iastate.edu
Organization: Iowa State University of Science and Technology, Ames, Iowa.
Date: Fri, 2 Oct 1992 23:07:21 GMT

In <johnr.718065036@mik.uky.edu> johnr@mik.uky.edu (john s roberts) writes:

>In <kennehra.718059469@craft.camp.clarkson.edu> kennehra@craft.camp.clarkson.edu (Rich"TheMan"Kennehan) writes:


>>Hi.  I was wondering if its possible to construct a garage door
>>opener that can broadcast on any frequency you want so that you can
>>open other people's garage doors as you drive by :)

>>- Rich


>I have also wondered about this, however there is more to it than just 
>locating the frequency, but also figuring out what type of code is sent.
>I have no idea where to start in figuring something like that out
>(I am just an EE freshman)  Good Luck

>John

One particular door is easy.  Just listen, with your radio, when the guy opens
his door, and  record the transaction.  Whenever, you want to open that 
particular door. Regenerate, the signal.  There are more sophisticated ways 
to open doors of highly graded places, but you just need to open one 
unprotected garage door. It's no fun at all.  

How to prevent this from happening to you.  Use coding based on time and date.
That is the transmitter in your hand sends signal to door opener. the door 
opener sends back the time and the date of it's internal clock. The transmitter
in your hand code your code based on time and date to door opener. The door
opener decodes the received code based on internal clock. if the decoded code
matches with preset value it opens the door. Here is the time chart of events:

Hand transmitter               time             Door Opener
---------------                  |              ------------
Sends intend package             |
                                 |               Receives Intend Package
                                 |               Sends the time stamp.
Receives time stamp              |
Codes based on time stamp        |
Sends coded request to open      |       
                                 |               Receives coded request to open
                                 |               Decodes based on it's internal
                                 |                       clock.
                                 |               Opens the door If the match
                                 |               Rings the alarm If it does not
                                 |                          match.
                                \ /
                                 V     

This is more interesting to break, than regular door opener.  Even though, 
there are ways to break this too. -:)

                     With highest regards,
                          Babak   Sehari.
From: musone@acsu.buffalo.edu (Mark J. Musone)
Newsgroups: sci.electronics
Subject: Modem carrier frequencies
Date: 2 Oct 92 14:24:45 GMT
Organization: UB


	I am currently working on a project and i am in dire need of some
telephone/modem information. Most importantly, I need to know what the
carrier frequency is for the answer mode and the originate mode of
standard telephones. Any other phone/modem information would
be greatly appreciated. (phone freq, voltages, resistances, modem voltages,
resistances...etc)

					Thanks,

					Mark Musone

					musone@acsu.buffalo.edu
					acscmjm@ubvms.cc.buffalo.edu
From: mdsp_ltd@uhura.cc.rochester.edu (Pooch)
Newsgroups: sci.electronics
Subject: Really Fast Data Transfer Question
Keywords: Really Fast 80386
Date: 6 Oct 92 21:02:33 GMT
Organization: University of Rochester - Rochester, New York

Easy Question --- Difficult answer.

  I need to transfer 8-bit data to an IBM pc clone (80386) at 8 MegaBytes/sec
for two sustained seconds.  I have no fear of creating my own custom interface
board, but I was wondering if anyone had thoughts.

  Things to consider:

  SCSI-2  I don't know if it will work, and I can't seem to get specs

  DMA     Would be the best answer, but can the 80386 deal with two seconds
          of DMA time?

  Custom 16Megabyte FIFO
          Really Expensive, but a possibility.


Please offer suggestions to mdsp_ltd@uhura.cc.rochester.edu

Thanks in advance.

Marc

-- 
+-------------------------------------------------------------------------+
|    Marc D. Spencer, C.E. WRUR-FM   | Technology is a way of organizing  |
|   mdsp_ltd@uhura.cc.rochester.edu  |  the universe so that man doesn't  |
|                                    |  have to experience it    -Frisch  |
From: aq456@cleveland.Freenet.Edu (Terry Quinn)
Newsgroups: sci.electronics
Subject: Need Help, Heathkit Clock
Date: 1 Oct 1992 02:24:03 GMT
Organization: Case Western Reserve University, Cleveland, Ohio (USA)
NNTP-Posting-Host: hela.ins.cwru.edu


I have an "antique" Heathkit GC-1005 Electronic Clock (circa 
1972).  After 20 years of faithful service, an electrical storm 
seemed to do it in (not a direct hit, but the problem started 
during the storm). The orange Sperry Rand SP-352 display segments 
are not all lit, and of those that are, they are only partially 
illuminated.  There is no indication of any clock timing function 
(display is static, no changes). 
 
The manual on the clock states . . .
 
        All the digital logic is performed inside of <the  
        integrated circuit>.  The remaining circuitry supplies the 
        DC power and responds to the commands from the <IC> to 
        drive the speaker and display tubes.
 
With this in mind, I started my investigation.  First, I noticed 
that if I touch a few of the pins of the IC at one location, 4 of 
the 6 display tubes illuminate fully (all 7 segments), and the 
remaining two blank out completely.
 
I next performed the voltage checks recommended in the owner's 
manual.  Voltages are measured with the IC removed, and specs call 
for +/-10% from nominal.  All voltages were withing this range 
except for a set of six pads that are supposed to be at 155 volts 
DC, and were instead ranged from 130 to 145 volts.  These pads 
appear to be the power feed for each of the 6 display segment 
sets, and per the owner's manual, should rise to 230 volts when a 
particular display tube is to be lit.
 
When I put a high impedence voltmeter on a pad feeding one of the 
4 tubes that lights during the "finger test" above, and then touch 
the IC with my finger, the voltage rises about 10 volts, but not 
anywhere near the 230 level described in the circuit fundamentals 
section of the manual. 
 
I really don't know what I am doing, but I'm guessing that maybe 
the integrated circuit is shot.  Does anyone know where I might 
find a replacement IC?  
 
It is a Mostek MK5017 (depending on what documentation I check, it 
is described as a MK5017AA, MK5017P, or MK5017A).  I have checked 
local electronic stores, the Heath Company (they don't stock it 
anymore) and JDR Microdevices in California.  Any suggestions for 
other sources would be appreciated, or if someone has one of these 
lying around, I'll buy it from you. 
 
If anyone thinks it isn't the IC or has any other ideas or things 
to check, please let me know.  The clock has more sentimenal value 
than anything else.
 
Thanks for your help.
-- 
                                    Terry Quinn
                                     Germantown Hills, IL
                                      tquinn@heartland.bradley.edu
                                       aq456@cleveland.freenet.edu
From: dino@inqmind.bison.mb.ca (Tony stewart)
Newsgroups: sci.electronics
Subject: Re: building a constant current power supply
Keywords: power supply
Date: 26 Sep 92 00:52:47 GMT
Organization: The Inquiring Mind BBS  1 204 488-1607

lehtin@ee.ualberta.ca (Ray 'Stingray' Lehtiniemi) writes:

> 
> 	I am currently working on a constant-current power supply to charge
> a large battery.  Is there anybody out there who has experience in building
> constant current, variable voltage power supplies in the 5 to 8 kW range? 
> The charger will be running off a 230V 30A outlet, putting out 160 - 300
> VDC at 12.2 amps. I need info on how to best accomplish this.  Please e-mail
> me (lehtin@bode.ee.ualberta.ca).
> 
> 		- Thanx

All you need is a current limiter using a Large Power transister, a 
current sense resistor that drops .7volts at current limit, a driver 
transister that senses the resistor voltage and turns off the POWER 
transistor. Use Large heat sinks and calculate the power drop around 
200V*12A=2.4KW. You could use liquid cooling on a parallel array of 
transistors to handle the current.

Sounds like an electric car battery charger!

A more efficient way is to use PWM control on a power transistor that can 
handle the VOLTAGE DROP and CURRENT going thru a power choke to reduce 
the ripple at say 50KHz using a torroid. PWM chips are easy to use, or 
just design one.

dino@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607
Newsgroups: sci.electronics