HDTenEightyP/NetNews huggingface dataset:
From: dcovell@hfglobe.intel.com (David Covell)
Subject: Tektronix ?
Organization: Intel Corporation
Date: Wed, 23 Dec 1992 16:06:31 GMT


I intend to buy a Tektronix TAS455 scope today (unless someone out there
has a good deal on a used Tek and responds VERY soon...). This will cost
me $1540 direct from Tek; is there a cheaper mail-order source for Tek
scopes?
I'm also interested in the following items, either new or clean used:

B+K transistor tester, models 520B or 510

Function generator

Triple-output power supply, preferrably with V and I metering

Isolation transformer, at least 250 KVA

Variac, at least 1KVA

Respond quickly, please. Money's burning a large hole in my pocket...
From: mike_d@tfsquad.mn.org (mike diack)
Newsgroups: sci.electronics
Subject: Care & Feeding of small Argon Laser
Date: Tue, 29 Dec 92 11:02:21 CST
Organization: tfsquad public access insane asylum, St Paul MN (+1 612 291 2632)

Recently (& more by good luck than good management) I aquired a small air
cooled argon laser head and exciter, Spectra Physics type 262. As this
machine, whilst fully functional, is in battered condition, i speculated
that it may benefit from a little tweaking. The first issue is the mirror
alignment - does anyone know of a standard procedure for this ?. Simply
twiddling screws seems pointless, as the feedback mechanisms (optical and
current) just try and compensate, until it gives up when too far out of
kilter. Speaking of feedback mechanisms, can these be fiddled to increase 
output, or is this likely to compromise plasma tube life. The tube 
currently seems to pull about 6 or 7 amps. Info from anyone about the
setup and output capabilities of the 262 would be appreciated.
cheers
        Mike

---
mike_d@tfsquad.mn.org (mike diack)
The Firing Squad BBS, public access Usenet mail and news.  +1 612 291 2632
Saint Paul, Minnesota
From: dino@inqmind.bison.mb.ca (Tony stewart)
Newsgroups: sci.electronics
Subject: Re: Magnetic Sensor?
Date: 3 Jan 93 15:35:18 GMT
Organization: The Inquiring Mind BBS  1 204 488-1607

Good magnetic sensors in disk drives , brushless DC motors or Car 
ignitions use Hall Effect sensors that provide a solid state or linear 
output with a change in magnetic field. Usually a notch or hole is 
sensed.

Cheaper sensors use magnetic switches when the contact frequency is low. 
REED RELAYS are such a device.


dino@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607
Xref: sparky sci.electronics:21435 sci.energy:6385 rec.autos:30369
From: rat@erg.sri.com (Ray Trent)
Newsgroups: sci.electronics,sci.energy,rec.autos
Subject: Re: Flywheel batteries as EV power source
Date: 23 Dec 92 01:59:33 GMT
Reply-To: rat@erg.sri.com (Ray Trent)
Organization: SRI International, Menlo Park, CA

In the referenced article, () writes:
>be contained by a container.  The object is not to stop the flywheel failure
>at any given point, but to slow it down and cause it to loose energy.  
>
>What I would like to see is a good treatment of the energy needed to turn a 
>flywheel into cotton candy.  This gives everyone a better idea of how 
>much energy is left yet to be contain by the next carbon carbon shell.

If a flywheel powered vehicle actually contained the same amount of
energy as an equivilent gasoline powered car, you're going to die
flaming death if they fail, but...

Is anyone here missing the point that flywheel powered cars need far
less total energy to go a certain distance (stop and go) than a
gasoline powered car? Car designers aren't completely stupid, you
know, they do try to recover kinetic energy during braking in a
vehicle that is capable of doing so (gasoline engines aren't). Also,
flywheel vehicles aren't really intended to provide as high a range as
gasoline powered vehicles, nor are they intended to be used for
towing. We're talking commuter cars here.

Additionally, gasoline engines are basically heat pumps. A large
percentage of the energy escapes in the form of heat out the exhaust
pipe in normal operation. This much energy, at least, would not
present in a flywheel.

Electric motors are much more efficient than gasoline engines, there's
absolutely no question about that...the inefficient part about using
electric motors in cars is getting the electricity into the car in
usable form (charging losses, discharging losses, efficiency of power
plants, efficiency of power lines, etc).

The actual amount of non-lossy energy it theoretically takes to get
from point A to point B is much smaller than you might think in terms
of heat.

Actually, though, the thing I'm curious about is: how do they manage
to find strong enough materials to make the mounts that connect the
counter-rotating flywheels? There's one hell of a lot of precessional
energy released in a change of orientation of even minor proportions,
and while they'd naturally balance *total* angular momentum (not being
total braindead idiots), I can't help but wonder...



-- 
"When you're down, it's a long way up
 When you're up, it's a long way down
 It's all the same thing
 And it's no new tale to tell"                      ../ray\..
Newsgroups: sci.electronics
Subject: Re: How full is a nicad
From: delinck@pa621a.inland.com
Date: 22 Dec 92 08:58:55 CDT
 <1992Dec19.230112.8340@klic.rain.com> <BzJFsH.4G4@zoo.toronto.edu>
Organization: Inland Steel Company, East Chicago, IN
Nntp-Posting-User: olenik

In article <BzJFsH.4G4@zoo.toronto.edu>, henry@zoo.toronto.edu (Henry Spencer) writes:
> In article <1992Dec19.230112.8340@klic.rain.com> keithl@klic.rain.com (Keith Lofstrom) writes:
>>>The output-voltage curve of a NiCd is essentially flat from pretty nearly
>>>full charge to pretty nearly empty.
>>
>>There are many applications where knowing the charge on the battery is 
>>crucial....one could provide a third electrode on a battery, of some other
>>materials ... designed to indicate the balance of electrolytes in the cell...
> 
> ...the temperature and ... pressure of a NiCd rise sharply when overcharging 
> begins. Premium-market NiCd systems often use cells with temperature or pres-
> sure sensors built in.

Some fast-chargers for NiCd powered RC model racing cars first discharge the
NiCd batteries to minimize "memory" effects, then charge the batteries at about
2.5 A. The charger monitors the rise in voltage. After about two minutes, the
battery will approach its operating voltage. It will go up about 2 more volts 
in 20 minutes. When the voltage begins to drop, the charger will change to a
trickle charge, and the battery is ready to use. These batteries are usually in
the range of 7.2 volts and 1 to 2 AH.
___________________________________________________________________________
 /\  Jeff Delinck              internet: delinck@pa621a.inland.com
/||\ Inland Steel              voice: 219-399-2445 fax: 219-399-5714
\||/ 3210 Watling St. MS 2-465
     East Chicago, IN 46312  USA
From: mike_d@tfsquad.mn.org (mike diack)
Newsgroups: sci.electronics
Subject: Strange microcontroller
Date: Fri, 01 Jan 93 14:20:58 CST
Organization: tfsquad public access insane asylum, St Paul MN (+1 612 291 2632)

Anyone ever heard of a microcontroller&/microprocessor called a
D77P20D ?. I met a few of these the other day, and a quick glance in
someone elses IC Master (mine is about 8000 miles away at present) told
me that it was a DSP optimised chip with a bloody fast multiply - well
compared to a '51 or 6805/11 anyway. My interest was aroused that these
could be useful in grotty little audio applications where the more fancy
(and expensive) DSP units were not needed. They are made by NEC and are
in a ceramic windowed package. To be useful, one would need to find an
X-assembler, and some data. Anyone know the phone number of the part of
NEC that deals in such obscurities ? (Oh that the IC Master really was
the fountain of info it purports to be instead of merely offering a 
morsel of information) - and while on the subject of strange thingies,
I'm looking for info on an "Omni programmer" made by Varix corp - what
seems to be now extinct !
Cheers,
        Mike.

---
mike_d@tfsquad.mn.org (mike diack)
The Firing Squad BBS, public access Usenet mail and news.  +1 612 291 2632
Saint Paul, Minnesota
Xref: sparky sci.electronics:21441 sci.energy:6389 rec.autos.tech:17092
From: mwilson@ncratl.AtlantaGA.NCR.COM (Mark Wilson)
Newsgroups: sci.electronics,sci.energy,rec.autos.tech
Subject: Re: Flywheel batteries as EV power source
Date: 23 Dec 92 02:16:37 GMT
Organization: NCR Engineering and Manufacturing Atlanta -- Atlanta, GA

In <olsen.42.725052409@vetmed.cvm.uiuc.edu> olsen@vetmed.cvm.uiuc.edu (Aart_Olsen) writes:

|In article <77846@ncratl.AtlantaGA.NCR.COM> mwilson@ncratl.AtlantaGA.NCR.COM
|(Mark Wilson) writes:
|>In <olsen.32.724613003@vetmed.cvm.uiuc.edu> olsen@
|vetmed.cvm.uiuc.edu (Aart_Olsen) writes:>
|>|In article <BzEsw7.57B@cs.uiuc.edu> morrison@cs.uiuc.edu
|(Vance Morrison) 
|writes:>

|>|>1) Slow down the rate of energy dumping. ...
|>
|>|This is what laboratory ultracentrifuges do.  Usually the rotor housing
|>|is contained in a thick bronze casing which "slowly" absorbs the kinetic 
|>|energy.  I once heard an ultracentrifuge blow, and it sounded like a freight
|>|train for maybe five minutes.  Lab centrifuges contain a surprising
|>|amount of energy--even though they have relatively small rotors and big 
|>|motors they take quite a while to get up to speed because so much has to 
|>|be pumped into them. 
|>
|>Do you happen to know how much one of the little beasties weighs.
|>

|Ultracentrifuge rotors weigh about 2-4 Kg.  They are maybe 15 cm diameter, 
|spin at 60-80KRPM.  I think the best of them these days develop 800 kilo-
|gravities at the tube ends (the tubes fit in the rotor).  They are the best 
|technology around, by the way; they are about as massive and rotate as fast 
|as current metallurgy reliably allows.

Very usefull information, thanks.  Do you know how much the containment
weighs.  The reason I am asking is somebody wants to put this thing in
a car so it will have to be light.

I don't have the equations handy, but from the size and speed of the rotor,
it doesn't sound like this thing has a fraction of the energy we have
been talking about in a flywheel battery.

-- 
Mob rule doesn't become any prettier, just because the mob start to call itself
a government.
It ain't charity if you are using someone else's money.
Mark.Wilson@AtlantaGA.NCR.com
Newsgroups: sci.electronics
From: despair@netcom.com (Scott Hanson)
Subject: Re: help needed building water level sensor
Organization: Netcom Online Communications Services (408-241-9760 login: guest)
Date: Wed, 30 Dec 1992 22:59:46 GMT

uchrgrh@Msu.oscs.montana.edu writes:
>I would like to build a solid state device that would turn off a water
>pump in my aquarium if the water level drops  below a certain level.
>I am willing to look at prefabricated stuff but would prefer to build it
>my self.
>I would like to put the level sensor on the prefilter which hangs over 
>the back of the tank and the rest of circuit in the cabinet below the tank.
>The reason for the circuit is mostly to save the pump, which relys on water 
>for lubrication, shoud it start to suck air.

If you don't want electrodes in the water, I have a pressure switch that 
will work.  Normally open, closes when there is higher than ambient pressure.
You could have it for $5 or so.  It seems to be intended for gases, but is
definitely water-tight.

Regards.
-- 
Scott Hanson		This has been a recording.
despair@netcom.com
Newsgroups: sci.electronics
From: luckey@rtfm.mlb.fl.us (Jon Luckey)
Subject: Re: Soundblaster for low rent data acquisition?
Organization: We don't need no stinkin' batches!
Date: Sun, 27 Dec 1992 22:17:24 GMT

phr@telebit.com (Paul Rubin) writes:

>I am interested in a cheap way to monitor some slowly changing
>voltages (read: DC) in a piece of test equipment.  8-bit resolution
>is fine.  I can scale the voltages to the 0-1 VDC range (or similar)
>using resistor networks if I need to.

I'd worry about common mode/ ground loop problems if you are using
any PC port as an A to D without some sort of DC isolation.

What I'd do is get a serial A to D convertor such as the Texas 
Instruments ADC831 or TLC549, probably the latter since its CMOS.

To interface to this you need two outputs from your PC and one
input.  I have used a printer port for projects like this.
With only three signals, you can power the ADC circuit from a battery,
avoiding grounding problem, and use opto-isolators to connect
to the PC.

Then to drive the software, you activate the CS chipselect to start
the conversion.  then pulse the I/O CLOCK line, sampling the input
to collect the serial bits.

It should be way cheaper than $79 if your time to build and program
is 'free'
 
to 
Newsgroups: sci.electronics
From: BrianW@SoundS.WA.com (Brian Willoughby)
Subject: Re: VCR parts
Reply-To: BrianW@SoundS.WA.com
Organization: Sound Consulting, Bellevue, WA, USA
Distribution: usa
Date: Wed, 30 Dec 1992 07:28:55 GMT

Steve Wechsler writes
| Does anyone know a good source to buy VCR idler tires?  Parts Express
| has them at what seems to be a good price, but they have a $20 minimum
| order, and the tires are only $.35-$.45 each.  Local repair shops (at
| least, one that I tried a couple of years go) only sell the whole
| idler assembly, which costs about $10-$15, and the idler needs to be
| replaced about once a year (bad design, I guess; it tends to dry out.
| I tried Radio Schlock non-slip compound; it didn't do much good).

I haven't owned a VCR as long as I've owned cassette decks, but I would assume  
that the following advice would be valid for VCR idlers as well as pinch  
rollers (since they are about the same).

I've been cleaning cassette deck pinch rollers for years with a special cleaner  
from Teac (Montebello, CA 90640).  It is called RUBBER CLEANER CONDITIONER and  
is sold along with a HEAD CLEANER solution for metal and plastic.  The stuff  
lasts a long time, and the last time I purchased a set was from a mail order  
catalog which sold professional recording studio equipment.  I've never used  
cleaning cassettes (on tape decks OR VCRs) because you cannot use the optimum  
cleaner for both metal and rubber parts.

Here are the directions on the bottle, just to let you know where they're  
coming from:

This fluid is specially formulated to clean and condition the pinch roller and  
any other /rubber/ parts on your tape recorder. We suggest that you clean the  
pinch roller every four to six hours of playing time or everytime you clean the  
heads and metal parts in the tape path. Apply the fluid with a clean, soft  
cloth or cotton swab. Leave on for one minute, then clean and dry with a soft  
cloth. Repeat this procedure until the cloth shows little or no residue.  
Regular application and cleaning will reduce the effects of ozone and smog  
which cause hardening and cracking of rubber parts.
CAUTION! TO AVOID DAMAGE DO NOT ALLOW CONTACT WITH PLASTIC.
CONTENTS:
aromatic hydrocarbon, antioxident. *This liquid contains NO ALCOHOL.
-- 
Brian Willoughby	Software Design Engineer, BSEE NCSU
BrianW@SoundS.WA.com	Sound Consulting: Software Design and Development
NeXTmail welcome	- NO EMAIL SOLICITATION without prior permission
From: karol+@pitt.edu (Filip M. Gieszczykiewicz (fmgst+@pitt.edu))
Newsgroups: sci.electronics
Subject: to the guy looking for 33K uF caps
Summary: sorry for post but I lost his address
Keywords: amp
Date: 3 Jan 93 16:43:18 GMT
Followup-To: na
Organization: University of Pittsburgh


	Greetings. If you're not looking for large caps, hit "n" now.

	Give MECI a call at 1-800-344-4465 and ask about part # 191-1894F
	It's a 30,000 uF electrolytic with 60V rating. These are "Computer
	Grade" whatever that means. The price is $17.02 each or $8.51
	for 5+

	If you want to OVERKILL, ask about part # 192-0218F which is rated
	for 75VDC and has a comfortable 230,000 uF capacitance! You pay
	for it, though, $37.56 or $18.78 for 5+

	Hope this helps. In case you need more than 75V you can always
	put 2 of the above in (let me see) parallel (me thinks).

	Take care.
-- 
-------------------------------------------------------------------------------
DO NOT REPLY HERE. REPLY TO "fmgst+@pitt.edu". THANK YOU. If that doesn't work,
send that e-mail to "fmg@alpha.smi.med.pitt.edu". Proud co-owner of a Jeanie's
Teenie serial# 1: all-Al, 285lb, low-wing, 53 hp, 120 knts, experimental plane!!
Xref: sparky sci.electronics:21878 alt.radio.scanner:3564 rec.radio.amateur.misc:21680
From: washer@sequent.com (Jim "Throw it over the wall" Washer)
Newsgroups: sci.electronics,alt.radio.scanner,rec.radio.amateur.misc
Subject: How to calculate crystal freq for scanner?
Date: 2 Jan 93 20:09:22 GMT
Article-I.D.: sequent.1993Jan2.200922.19977
Organization: Sequent Computer Systems, Inc.

I have a radio shack Pro-24 crystal controlled scanner..... (yep, poor me).
It uses a 10.7MHz IF, and says to use third overtone crystals...

So, am I correct in  calculating the crystal fundamental as:

F(fund)*3 + 10.7MHz == Receive Freq?

 - jim washer@sequent.com
From: athos@apple.com (Rick Eames)
Newsgroups: sci.electronics
Subject: Yet Another Descrambler Question...
Date: 31 Dec 92 05:09:55 GMT
Followup-To: sci.electronics
Organization: Apple Computer, Inc.

I recently found this newsgroup, so if I am bothering people, please be
patient.  A friend of mine's father just had his descrambler (8 years old)
zapped by the cable company.

How in the hell can they do this? I could understand on the new two-way
systems, but on the old A/B one-way systems, how could they "zap" a system?
 If they can do this, how could one defeat it?

******************************************************************************
Rick Eames                               My Opinions Are My Own (not
Apple's)
athos@apple.com
Don't blame me, I didn't vote for Boxer.
******************************************************************************
From: rays@elm.lle.rochester.edu (Ray Stewart)
Newsgroups: sci.electronics
Subject: How does color guard work on video tapes?
Date: 23 Dec 92 20:26:46 GMT
Organization: University of Rochester Computing Center

How does color guard work? I have notice that once in a while the color on some
of the movies I rent get real wavey.  I was wondering is there some easy way to
prevent this?

Thanks

Ray.
--
-----------------------------------------
Standard disclaimers are in full effect.
Xref: sparky sci.electronics:21664 sci.energy:6484 rec.autos:30633
From: stead@skadi.CSS.GOV (Richard Stead)
Newsgroups: sci.electronics,sci.energy,rec.autos
Subject: Re: Flywheel batteries as EV power source
Date: 29 Dec 92 01:21:59 GMT
Followup-To: sci.energy

In article <1hb3nkINNmgv@usenet.INS.CWRU.Edu>, wb8foz@skybridge.SCL.CWRU.Edu (David Lesher) writes:
> Others said:
> # It doesn't sound like you have been listening either.  In the event of
> # a catastrophic failure, gasoline burns, it does not explode.  The energy
> # contained in the tank is released over a period of 15 to 20 minutes.
> # 
> # The flywheel will try to dissipate it is energy over a span of milliseconds.
> 
> Errr,
> Try telling the three people who burned to death in the tanker/
> multi-car crash at the I 270/Beltway intersection that it is ok that
> gasoline burns over 15-20 minutes. That may be true, but they are still
> dead, regardless of how long their remains cooked.

I am fully aware of that disaster.  Note that several people survived who were
involved in the accident including one who drove through the flames.  Now
would those people have preferred something that released its energy so
quickly that they, too, would not have gotten out alive?

I was not trying to pretend gasoline is not dangerous.  It is just much less
dangerous than a flywheel explosion.  The distaster you point to should only
make people that much more wary of this flywheel proposal.  Now, I have
also pointed out that no flywheel portable in a car can be designed to
store the energy required, so we needn't really worry about such an explosion.
That is part of the argument.  Also, the tanker truck contains 1000's of
gallons of gas.  Its fire is much more devastating than anything a little
10 gallon gas tank can generate.


--
Richard Stead
Center for Seismic Studies
Arlington, VA
stead@seismo.css.gov
From: cab@col.hp.com (Chris Best)
Newsgroups: sci.electronics
Subject: Re: Railroad crossing gates -the ups and downs???
Date: 21 Dec 1992 16:27:07 GMT
Organization: your service
NNTP-Posting-Host: hpctdke.col.hp.com

> The old style worked by detecting a short circuit between the rails 
> (a locomotive is pretty conductive). If you walk the track near a
> crossing and pay attention to where the rail ends meet, you will see
> that some are electrically connected and some are isolated. You will
> also find cables connected to the rails running under-ground toward
> a nearby electrical box which controls the whole thing.

----------

Indeed, the old style worked by shorting the rails.  Used to be, you
could connect the rails together with jumper cables, and the gates
would activate, or a nearby block signal would turn green (trust me).

That was in my childhood - but not long ago, I tried the same thing 
near a protected crossing, and nothing happened.  At the time, I just
figured that the equipment was smarter, and knew better than to
respond to a "train" that just appeared on a block without being on
an adjacent block first.

So I had that part right, but I don't see why they'd change the
sensing scheme - just the interpreting curcuitry.  But if the
guy who "drives the big trains" sez so, I guess it's so...
Newsgroups: sci.electronics,sci.energy,rec.autos.tech
From: olsen@vetmed.cvm.uiuc.edu (Aart_Olsen)
Subject: Re: Flywheel batteries as EV power source
Organization: UIUC -- Vet Med
Date: Tue, 22 Dec 1992 19:26:49 GMT

In article <77846@ncratl.AtlantaGA.NCR.COM> mwilson@ncratl.AtlantaGA.NCR.COM
(Mark Wilson) writes:
>In <olsen.32.724613003@vetmed.cvm.uiuc.edu> olsen@
vetmed.cvm.uiuc.edu (Aart_Olsen) writes:>
>|In article <BzEsw7.57B@cs.uiuc.edu> morrison@cs.uiuc.edu
(Vance Morrison) 
writes:>

>|>1) Slow down the rate of energy dumping. ...
>
>|This is what laboratory ultracentrifuges do.  Usually the rotor housing
>|is contained in a thick bronze casing which "slowly" absorbs the kinetic 
>|energy.  I once heard an ultracentrifuge blow, and it sounded like a freight
>|train for maybe five minutes.  Lab centrifuges contain a surprising
>|amount of energy--even though they have relatively small rotors and big 
>|motors they take quite a while to get up to speed because so much has to 
>|be pumped into them. 
>
>Do you happen to know how much one of the little beasties weighs.
>

Ultracentrifuge rotors weigh about 2-4 Kg.  They are maybe 15 cm diameter, 
spin at 60-80KRPM.  I think the best of them these days develop 800 kilo-
gravities at the tube ends (the tubes fit in the rotor).  They are the best 
technology around, by the way; they are about as massive and rotate as fast 
as current metallurgy reliably allows.
-----------------------------------------------------------------------------
Aart M. Olsen   University of Illinois at Urbana-Champaign   a-olsen@uiuc.edu
-----------------------------------------------------------------------------
Newsgroups: sci.electronics,rec.audio.pro
From: rth@netcom.com (Robert Hughes)
Subject: Speaker phase checker circuit?
Followup-To: poster
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Date: Mon, 4 Jan 1993 01:57:52 GMT

There are a couple of somewhat expensive phase checking devices on the market. 
One box feeds the popping signal into the amp and the other box has a mic
with an indicator showing the signal at the mic is either in phase
or out. Has anybody seen a public domain circuit or kit to build
one? 

rth@netcom.com


Newsgroups: sci.electronics