chip swelling up and getting fried

[John Fields]

On Sat, 31 Jul 2004 20:43:22 GMT, Don Bruder <dakidd@sonic.net> wrote:

Now to refine the idea...

Although the "filter" I built is functional, it seems to be doing a bit
too good of a job in scattering the light - Almost certainly due to the
fact that my method of removing the reflective material from the base
plastic of the CD left what's probably best described as a crude "ground
glass" finish on it - Instead of being the usual pristine "It's so
clear, it's like nothing is there at all" plastic, my scrubbing to
remove the coating has created a more-or-less matte finish that doesn't
transmit anywhere near as well as I had hoped. Kind of like a lens that
has somehow escaped from its proper holder, then spent the last few
months bouncing around in the bottom of your ditty-bag with all kinds of
things that a lens isn't supposed to associate with if it's going to
remain unscratched and clear until it has become "frosted" by all the
scratches it has acquired.

So at this point, I'm trying to figure out the best way to polish out
the scratches left by the steel wool, and get back to a truly
transparent (rather than translucent) finish on my homemade "filter".

Is there a reasonably easy way to do so? I don't know... I went after
the thing with 4-0 steel wool - as fine as I know how to locate - under
a layer of 40-weight motor oil, and although I did my best to avoid
excessive scrubbing (and therefore, scratching) I ended up with a
semi-matte, and therefore semi-translucent, finish on the filter. My
next move is probably to a 2400-grit wet/dry sandpaper that bills itself
as "Mirror-Brite", and to the touch, feels just about as abrasive as a
sheet of regular printer paper.

From there, my guess is that I'm going to need to move to something like
rubbing compound, rottenstone, or even ultra-fine jeweler's rouge.

Does this seem reasonable to those who have done optical grinding work?

Or am I way off base here?

---
You're probably OK, if you want to go through the ritual of
never-ending polishing, but there _are_ commercially available
polishing compounds out there which might make your life easier.

Check out

http://www.noscratch.com/novus/index.shtml

Or, you might want to go a completely different route and use an
acrylic designed specifically for the purpose.

Cyro Industries has infrared transmitting acrylic, "ACRYLITE GP" with
a color # of 1146-0 which ought to work for you. Check this out:

http://cyro.custhelp.com/cgi-bin/cyro.cfg/php/enduser/std_alp.php?p_sid=rANE2Bih&p_lva=&p_li=&p_page=1&p_prod_lvl1=4&p_prod_lvl2=6&p_cat_lvl1=%7Eany%7E&p_cat_lvl2=%7Eany%7E&p_search_text=1146-0&p_new_search=1&p_search_type=3

for spec's.

--
John Fields

 

[Oppie]

"John Woodgate" <jmw@jmwa.demon.contraspam.yuk> wrote in message >

Strictly speaking, wallboard is Gypsum which is magnesium sulphate.

Gypsum, yes, but magnesium sulfate is Epsom salts. Perhaps the building
was indeed evacuated. (;-)

<groan! but a good one John>

Er, Calcium Sulphate. I do stand corrected.
CaSO4ˇ2H2O

 

[Rich Grise]

pil wrote:

Hi, I am still having trouble with my amplified ear. I noticed that my
headphones have a dc resistance of 16ohms per ear piece. The ones
specified in amplified ear has impedances of 32 ohms wired in series to
create a 64ohm load on Q4.

Could this be why my circuit does not work?

It _could_ be, but it could also be any number of other things. You
haven't shown any component values here. Do you even have a meter?
Is the mic known good? Have you double-checked all your connections?

We need much more to go on here.

Good Luck,
Rich

 

[Don Bruder]

In article <ssthh0l2thu46jc2or3n8n7n27pde6f97n@4ax.com>,
John Fields <jfields@austininstruments.com> wrote:

Or, you might want to go a completely different route and use an
acrylic designed specifically for the purpose.

Cyro Industries has infrared transmitting acrylic, "ACRYLITE GP" with
a color # of 1146-0 which ought to work for you. Check this out:

http://cyro.custhelp.com/cgi-bin/cyro.cfg/php/enduser/std_alp.php?p_sid=rANE2B
ih&p_lva=&p_li=&p_page=1&p_prod_lvl1=4&p_prod_lvl2=6&p_cat_lvl1=%7Eany%7E&p_ca
t_lvl2=%7Eany%7E&p_search_text=1146-0&p_new_search=1&p_search_type=3

for spec's.

Hmmm... that one has possibilities, though I cringe at the idea of how
much $$ it will take to get ahold of the stuff... When looking at
IR-transmitting photographic filters, I was routinely spotting prices in
the $150-$200/6 inch square range for plastic filters - Which is why I
ended up going with a "make-do" chopped out of a black CD-R. Even the
gell filters (which are very likely to have *VERY* short working
lifespans) to transmit IR were ridiculously priced - a 70MM round was
tagged at $89, fergawdsake! My budget (which is mostly imaginary,
practically speaking) for this project can't even CONSIDER those kind of
prices! And glass? HAH! If I can't afford the "cheap" gells and/or
plastic, then I don't even need to consider glass, since that seems to
routinely be about 130-200% more expensive than the corresponding
plastic filter.

Now to see if I can find someplace that will tell me how much this
"Acrylite" stuff costs... I note a glaring lack of any reference to
pricing for it at the link you posted. Most often, I've found that
situation to be a red-flag for "If you need to ask "how much?", it's
more than you can afford. Have a nice day, and don't let the door hit
you in the arse as you leave." materials.

Still, now that I know the stuff exists, I might be able to find
someplace that sells it in reasonable quantities, at reasonable prices.
More investigation is in order, obviously...

--
Don Bruder - dakidd@sonic.net - New Email policy in effect as of Feb. 21, 2004.
Short form: I'm trashing EVERY E-mail that doesn't contain a password in the
subject unless it comes from a "whitelisted" (pre-approved by me) address.
See <http://www.sonic.net/~dakidd/main/contact.html> for full details.

 

[TheDoc]

"Makhan" <makhan_rocks@hotmail.com> wrote in message
news:60f42c64.0408100818.1f967bd9@posting.google.com...

Thank you all for the discussion, I am afraid there is more to it than
I first wrote.

Actually, there is an array of microcontrollers each doing identical
job, that is lighting up a multiplexed LED array (of variable
characters) and the characters to display are configurable ofcourse,
i.e. user can choose to display any information onto the array(s).
Each micro corresponds to one row.

So there we go. I thought of giving an identity (any character 0xA0
and so on) each, to the microcontrollers for the rows and initially
the idea was on identity match, update the allocated IDATA space with
the charcters, else just ignore.

Why not use 9 bit mode with an "address" as your identity ?

But can you please comment on the fact that if I go for filing the
buffers on each serial port interrupt I will end up writing and
rewriting all the micros with same data?

Thanks

Makhan


Dan Henry <dhenry@sprynet.com> wrote in message
news:<1q1dh09vrjdf5qgdiu9lbg20mho7c291ic@4ax.com>...
makhan_rocks@hotmail.com (Makhan) wrote:

So the ISR goes like:

ISR_SP:
JBC TI, QUITY ; if TI caused it, just quit
MOV A, SBUF ; if '0' = 30 then update the IDATA
ADD A, #-30H ; else skip the update
JNZ QUITY
SETB UpdateFlag
QUITY:
RETI ; if TX irq just returns

One problem that has not been mentioned by others (at least in
c.a.e.), is that your ISR does not save and restore ACC and PSW.

Oops!

 

[Rich Grise]

Watson A.Name - "Watt Sun, the Dark Remover" wrote:

And finally, I think I should differentiate the engineer and tech. Re:
fixing a broken flashlight, that's the tech's method. The engineer will
rip out the incandescent light bulb and replace it with a Luxeon Star
LED, and put some lithium cells in there, too!

No, the engineer dashes off a schematic on the back of an envelope of a
flashlight with the incandescent bulb ripped out and replaced with a Luxeon
Star LED, and some lithium cells, too; and hands it to the tech to build it,
using, typically, stone axes and animal skins. ;-)

Cheers!
Rich

 

[Watson A.Name - \"Watt Su]

"John Woodgate" <jmw@jmwa.demon.contraspam.yuk> wrote in message
news:FdpEhhEoLOGBFwOK@jmwa.demon.co.uk...

I read in alt.binaries.schematics.electronic that Watson A.Name -
"Watt
Sun, the Dark Remover" <NOSPAM@dslextreme.com> wrote (in
10hh3hsrdnmih7
0@corp.supernews.com&gt about 'More of the Parker Advertisments', on
Tue,
10 Aug 2004:

After all, the contractor was only playing with gypsum
wallboard, which is just a kind of sand..

You can turn calcium sulfate into silicon dioxide? Tell Uncle Al
immediately!

Sand isn't just made of silicon. Ask any Hawaiian. ;-)

But even if the wallboard didn't have any silicon, that has nothing to
do with the low yields. That was caused by the dust from the wallboard
getting thru the filtering system.

--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Watson A.Name - \"Watt Su]

"Oppie" <boppie@-nospam-ludl.com> wrote in message
news:EG5Sc.27816$V96.18976@cyclops.nntpserver.com...

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote
in message news:10hh3hsrdnmih70@corp.supernews.com...
"Oppie" <boppie@-nospam-ludl.com> wrote in message
news:12TRc.25247$_C6.17677@cyclops.nntpserver.com...
I still haven't been able to find anybody at Parker Corporate that
can
help
me get posters of the "I am an Engineer... Engineers see the world
differently" advertising campaign. Nobody at corporate seems to
know
what
this is about. 'guess this happens when companies get that large.

A couple comments on the following.

Re: pill, if everyone thought like an engineer, then there would be
no
need for that profession, hence the engineer would suffer the same
fate
that consumer electronic techs suffered in the '70s and '80s: most
consumer electronics techs became unemployed when the price of TVs,
etc., became so low that it was cheaper to buy a new one than fix
the
old one.

= Yeah, it seemed sort of elitist.

Re: outer space: I really loved that one that showed an astronaut in
his
space suit talking on a two-way hand-held walkie-talkie! Like,
Right...

= <grin

I'm still trying to figure out the implications of this one:
I believe "drug discovery" is more than
just a phase some people go through in college.

= 'Drug discovery' is the formal name to researching for the purpose
of
coming up with new pharmaceuticals. Nice double meaning though.

Yeah, I grok that, but what's it got to do with engineering?

I find the following two mutually contradictory.
I would vote for the first one taking precedence.

I believe a man with a semiconductor
is still no match for a woman.
editorial comment: that's messed up!

I believe there's nothing more exciting
than a submicron package.

Re: "playing with sand", I consider that an extremely severe
understatement. Like, grains of sand aren't submicron!! It's gone
a
l-o-n-g way past the point of playing!! Seriously!!

Years ago, back when there was a local memory wafer plant that
needed
expanding, the company got a contractor to build an addition onto
the
bldg. The production yield went down to 40% when the contractor
started
working. After all, the contractor was only playing with gypsum
wallboard, which is just a kind of sand..

= Strictly speaking, wallboard is Gypsum which is magnesium sulphate.
Sand
is Silicon Dioxide.

Well, as I was implying in another followup, that's like saying all
four-legged animals are horses. There's nothing that says that sand has
to be exclusively silicon. In Hawaii, the beaches might be black
because they're almost pure igneous rock. In some other parts of the
world, the sand on the beach might be almost pure coral, and *that* is
almost all calcium.

And you go to a store that sells such stuff as sand, cement, etc, and
you buy some sand and you might get "DG", or decomposed granite, which
is definitely not pure silicon, and probably has a lot of calcium in it.
Anyway, you get what I mean.

As you know, between any vibration which can really mess up an IC
manufacturing process and extra contaminants for the filtration
process to
handle, definite effect on yields.

Yeah, I hadn't thought about vibration. But the main reason for the low
yields was the contaminants caused by the filters letting a minute
amount of particulates thru.

And finally, I think I should differentiate the engineer and tech.
Re:
fixing a broken flashlight, that's the tech's method. The engineer
will
rip out the incandescent light bulb and replace it with a Luxeon
Star
LED, and put some lithium cells in there, too!

= Dunno, I'm an engineer by way of the workbench. I like simple fixes
but
could see myself repairing a flashlight.
Oppie

Well, I'm taking a bit of literary license for effect. After all, I
think there was something in the credoes you posted about making the
place a better world, and seeing things differently. And fixing
something that's broken is something that's gratifying, as a tech I know
from first-hand experience. But making something that's broken better
and seeing the improvements one could make differently, seem to me to be
in the true engineering tradition.

But just one other thing. Those idiots in personnel, er, human
resources have botched things up so badly by calling pencil pushers
'technicians' and field technicians 'field engineers' that it's
difficult to tell just who's who nowadays. :-(

Next week I have to go to HQ for a 90 minute interview about my job.
The district hired an outside company to 'evaluate' our occupations, so
a few months ago we received an hour briefing and a handful of paperwork
called a 'PDQ', position description questionnaire, that we all spent
hours filling out. So then our schmuck bosses gave us some of the
inside paperwork, (sort of like the instructor's manual), started
telling us what they wanted to see in a rewrite of the PDQ, and the
union cried 'FOUL!' and said that that was giving our group an unfair
advantage. So they had to schedule each of us for an in-person
interview just to get things straight and on the up-and-up.

God, I love(?) the bureaucracy.. Back in the '80s, They found that I
was getting overpaid so they froze my COLAs until the others caught up.
I hope the outcome is a lot better this time.

 

[Watson A.Name - \"Watt Su]

"Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:10hhr7jb7n5bs10@corp.supernews.com...

Years ago, back when there was a local memory wafer
plant that needed expanding, the company got a contractor
to build an addition onto the bldg. The production yield
went down to 40% when the contractor started working.
After all, the contractor was only playing with gypsum
wallboard, which is just a kind of sand..

= Strictly speaking, wallboard is Gypsum which is magnesium
sulphate. Sand is Silicon Dioxide.
As you know, between any vibration which can really mess
up an IC manufacturing process and extra contaminants for the
filtration process to handle, definite effect on yields.

We freaked when Mt. St. Helens (in S.W. Washington state,
but quite prominent from anywhere in the Portland, Oregon
area) blew because of all the very fine ash in the air. It was
just a horrible mess. The auto parts stores sold out of air filters
by the next day. Many of us had to replace our gutters because
the ash turned to concrete if you let it get wet without washing
it away immediately.

At the entrance to our fab buildings we had people with vacuum
cleaners going over our outer clothes before we could enter the
building. We also introduced some vacuum shoe-cleaners that
collected a remarkable amount of grime. And then there were
the "wind-tunnel" passageways where you walked through a
pretty stiff breeze on your way into the cleanroom.

End result of all the extra microcontamination measures was that
the particle counts inside the fabs went DOWN after the volcano
erupted. We have kept several of those extra measures in place
ever since. Its tough keeping a space at class-1 with all those
filthy humans that you have to let in.

Sounds a lot like ST TOS "Veeger", and its aversion to carbon-based
lifeforms.

Hey, don't they call it dandruff??

 

[Michael A. Covington]

"bruce racicot" <bracicot@cfl.rr.com> wrote in message
news:d22eda7.0408102012.4df370c8@posting.google.com...

I have a pair of ADS car speakers I was thinking of using as surround
speakers in my home system. My question is; can I damage my amplifier
running 4 ohm speakers? My receiver has the capability of switching
impedances, but it only toggles between 8 ohm and 6 ohm loads. Can I
just get some 4 ohm resistors and solder them inline to bring the
speaker impedance up to 8 ohms?

That would bring up the impedance, but the damping factor would be very poor
and the speakers would sound as if they were being driven by a much smaller
amplifier.

 

[John Woodgate]

I read in alt.binaries.schematics.electronic that Watson A.Name - "Watt
Sun, the Dark Remover" <NOSPAM@dslextreme.com> wrote (in <10hj4kvcrpm6id
2@corp.supernews.com&gt about 'More of the Parker Advertisments', on Tue,
10 Aug 2004:

Well, as I was implying in another followup, that's like saying all
four-legged animals are horses. There's nothing that says that sand has
to be exclusively silicon.

Silicon dioxide, not just silicon. In any case the context is 'engineers
playing with sand' - i.e. making semiconductors.

In Hawaii, the beaches might be black
because they're almost pure igneous rock.

Guess what igneous rock has as major constituents. Silicates.

In some other parts of the
world, the sand on the beach might be almost pure coral, and *that* is
almost all calcium.

Calcium carbonate.

And you go to a store that sells such stuff as sand, cement, etc, and
you buy some sand and you might get "DG", or decomposed granite, which
is definitely not pure silicon, and probably has a lot of calcium in it.
Anyway, you get what I mean.

DG is mostly magnesium, iron and potassium silicates, with maybe a
little aluminium, uranium and/or thorium silicate.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Graham Knott]

Johan Wagener wrote:

All connections double checked. All transistors checked and the all
have 0.8V on BE. Except for transistor 2 which has 1V over its BE?

Mic is a brand new miniature electret microphone which runs on 1V-10V
with 2Vnom

I don't even pick up the mains hum when I touch the input. I do
however get a small amplification of the microphone and when I connect
a 3V supply to the circuit I can hear sounds picked up by the mic, but
it is very faint.

Should I perhaps try using a LM741 as a preamp for the mic and then
send this signal into the Amplified Ear?

BTW, the circuit can be found at
http://www.electronics-lab.com/projects/audio/023/

Please send your suggestions

--
Measure emitter, base and collector voltages with respect to the negative
supply for all transistors and post them here (unless you've already done
so)
..
My most up-to-date website
Electronics for Beginners & Intermediate Electronics
http://homepage.ntlworld.com/g.knott/index.htm

 

[Don Bruder]

In article <d36a713e.0408110632.299b59de@posting.google.com>,
chrisjhodges@yahoo.com (Chris Hodges) wrote:

I modelled the blackbody curves in excel, and you're right, by quite a
margin - I don't know whether the power requirement or the IR output
would fall faster for a given emitter as you drop the temperature
(assuming temperature control for convenience) so it might not even
save battery life.

Nice to find out that the numbers match my world picture Seriously!
I was having a hard time swallowing the idea that IR output would
increase (in any way other than relative to the amount of visible light)
due to a voltage drop.

The maglite could be a good way to go - the focussing output would
seem to help, even if you have a diffuser effect from the vis blocking
filter.

Indeed. I'm thinking that no matter what the raw light source ends up
being, whether a "pure IR" source without filtering, or a filter system
in front of a visble source, it will be mandatory to have a
variable-focus beam.

Did you ever try multiple visible gel filters - these tend to be cheap
(I seem to remember ?10 (~$18)/sq foot), and for a maglite even
offcuts would be enough, so even cheaper if you have a friendly
theatrical/DJ supplies shop that does stage lighting.

That has been suggested, but at this point, I've done nothing with it.
At the very least, it seems to me that it would be worth trying.

I can have a look with a lamp and digital camera later. With anything
less than hundreds of watts they'll last forever.

Hmmm... maybe it's just me and my misinformation, but I've always been
under the impression that gels are the "cheap to buy this one, but
expensive as hell in the long term due to needing frequent replacement"
solution. My limited time "on the boards" (credited in the program as
"Soldier with a line" - <chuckle&gt in a 6 week run of Jesus Christ
Superstar at a local playhouse showed me a lighting guy *CONSTANTLY*
griping about needing to chase up into the flys to replace gels -
sometimes before each run of the show, and particularly the reds. From
that, I reached the conclusion that gels are, at best, a "make-do",
rather than a permanent solution. And the prices... <choke> At one
point, I overheard him saying something like "There goes another hundred
bucks" while he was working on cutting a blue one to shape.

--
Don Bruder - dakidd@sonic.net - New Email policy in effect as of Feb. 21, 2004.
Short form: I'm trashing EVERY E-mail that doesn't contain a password in the
subject unless it comes from a "whitelisted" (pre-approved by me) address.
See <http://www.sonic.net/~dakidd/main/contact.html> for full details.

 

[John Fields]

On Tue, 10 Aug 2004 19:48:24 GMT, Don Bruder <dakidd@sonic.net> wrote:

Hmmm... that one has possibilities, though I cringe at the idea of how
much $$ it will take to get ahold of the stuff... When looking at
IR-transmitting photographic filters, I was routinely spotting prices in
the $150-$200/6 inch square range for plastic filters - Which is why I
ended up going with a "make-do" chopped out of a black CD-R. Even the
gell filters (which are very likely to have *VERY* short working
lifespans) to transmit IR were ridiculously priced - a 70MM round was
tagged at $89, fergawdsake! My budget (which is mostly imaginary,
practically speaking) for this project can't even CONSIDER those kind of
prices! And glass? HAH! If I can't afford the "cheap" gells and/or
plastic, then I don't even need to consider glass, since that seems to
routinely be about 130-200% more expensive than the corresponding
plastic filter.

Now to see if I can find someplace that will tell me how much this
"Acrylite" stuff costs... I note a glaring lack of any reference to
pricing for it at the link you posted. Most often, I've found that
situation to be a red-flag for "If you need to ask "how much?", it's
more than you can afford. Have a nice day, and don't let the door hit
you in the arse as you leave." materials.

---
Cyro makes the stuff, and sells it through distribution, so you may
want to check with one of your local plasic suppliers to see if they
can help you out. Also, Cyro has a list of their distributors on
their web site, so you may want to check that out.
---

Still, now that I know the stuff exists, I might be able to find
someplace that sells it in reasonable quantities, at reasonable prices.
More investigation is in order, obviously...

---
I have a small quantity on hand and, depending on how much you need,
might be able to help you out at my cost plus freight. (Or a straight
swap for a bottle of a decent Chardonnay?-)

Email me if you're interested.

--
John Fields

 

[Don Bruder]

In article <6bhkh052o8ucj063s1ip23qki88aqoqr5f@4ax.com>,
John Fields <jfields@austininstruments.com> wrote:

Now to see if I can find someplace that will tell me how much this
"Acrylite" stuff costs... I note a glaring lack of any reference to
pricing for it at the link you posted. Most often, I've found that
situation to be a red-flag for "If you need to ask "how much?", it's
more than you can afford. Have a nice day, and don't let the door hit
you in the arse as you leave." materials.

---
Cyro makes the stuff, and sells it through distribution, so you may
want to check with one of your local plasic suppliers to see if they
can help you out. Also, Cyro has a list of their distributors on
their web site, so you may want to check that out.
---

Still, now that I know the stuff exists, I might be able to find
someplace that sells it in reasonable quantities, at reasonable prices.
More investigation is in order, obviously...

---
I have a small quantity on hand and, depending on how much you need,
might be able to help you out at my cost plus freight. (Or a straight
swap for a bottle of a decent Chardonnay?-)

Email me if you're interested.

We might just get something going, though it will likely be cash, since
I wouldn't know a decent chardonnay from vinegar if it walked up and
introduced itself to me. I'm basically a teetotaller - the "non
preaching" kind - mainly due to lack of any interest. By my own personal
drinking habits, buying a six-pack of Guinness, or, in a pinch, Bud
long-necks, and killing it off inside of six months qualifies as a
"major bender".

Keep an eye on your in-box...

--
Don Bruder - dakidd@sonic.net - New Email policy in effect as of Feb. 21, 2004.
Short form: I'm trashing EVERY E-mail that doesn't contain a password in the
subject unless it comes from a "whitelisted" (pre-approved by me) address.
See <http://www.sonic.net/~dakidd/main/contact.html> for full details.

 

[Rich Grise]

Watson A.Name - "Watt Sun, the Dark Remover" wrote:

And you go to a store that sells such stuff as sand, cement, etc, and
you buy some sand and you might get "DG", or decomposed granite, which
is definitely not pure silicon, and probably has a lot of calcium in it.

Is that what they're making in those prison movies where the guys
are whacking the big rocks with sledge-hammers? ;-)

 

[Mark Haase]

In article <4119b17a$1@mustang.speedfactory.net>,
"Michael A. Covington" <look@ai.uga.edu.for.address> wrote:

That would bring up the impedance, but the damping factor would be very poor
and the speakers would sound as if they were being driven by a much smaller
amplifier.

Wouldn't the resistors also need to sink a ton of power? How much would
such a resistor cost? (If you can get it?) Would it need to be
heatsinked?

--
|\/| /| |2 |<
mehaase(at)sas(dot)upenn(dot)edu

 

[Jim Thompson]

On 10 Aug 2004 21:12:23 -0700, bracicot@cfl.rr.com (bruce racicot)
wrote:

I have a pair of ADS car speakers I was thinking of using as surround
speakers in my home system. My question is; can I damage my amplifier
running 4 ohm speakers? My receiver has the capability of switching
impedances, but it only toggles between 8 ohm and 6 ohm loads. Can I
just get some 4 ohm resistors and solder them inline to bring the
speaker impedance up to 8 ohms?

thanks, bruce

I suspect it can drive 4 ohms just fine, just don't turn it up
full-tilt or you'll get current overload.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Michael A. Covington]

"Mark Haase" <mehaase@earthlink.net> wrote in message
news:mehaase-287C5B.15500111082004@netnews.upenn.edu...

In article <4119b17a$1@mustang.speedfactory.net>,
"Michael A. Covington" <look@ai.uga.edu.for.address> wrote:

That would bring up the impedance, but the damping factor would be very
poor
and the speakers would sound as if they were being driven by a much
smaller
amplifier.

Wouldn't the resistors also need to sink a ton of power? How much would
such a resistor cost? (If you can get it?) Would it need to be
heatsinked?

Indeed!

 

[Ken Smith]

In article <6277e9f4.0408120344.26184b23@posting.google.com>,
Shmuel Davis <eza@excalibur.co.il> wrote:
[....]

The device is contained within a metallic box that is completely
isolated.

Imagine a walk across a carpet and touch the box. A spark jumps from my
hand to the metal box. Where does it go from there on its way back to the
earth?

--
--
kensmith@rahul.net forging knowledge