Driver to drive?

[Guy Macon]

Paul Burridge wrote:

I don't understand why everyone is recommending a 100mhz scope!

It depends on what you want to do with it. I haven't dealt with
a clock rate higher than 20 MHz in years, and 99% of my work is
with clock rates of 1 MHz or less.

You can take my Tektronix 465B away when you pry my cold, dead
fingers off of the A Trigger Holdoff knob...

 

[Nicholas O. Lindan]

"John Larkin" <jjlarkin@highlandSNIPtechTHISnologyPLEASE.com> wrote

Leave the screws in plain sight. They make a statement: This Product
Is Held Together By Screws.

The heads can be 'semi-decorative', SS hex button-head screws for
instance. Or hex cap screws for an industrial look.

Screws under an overlay make servicing a pain. And the manufacturer
is the #1 servicer, so make things easy on yourself.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com

 

[John Larkin]

On 27 Oct 2004 18:38:46 -0700, Winfield Hill
<Winfield_member@newsguy.com> wrote:

Dozens of locked bunkers were not inspected for their contents at that
time, so any assertion now that they were empty then has to ring hollow.

"Pentagon officials admit the facility was not completely secured between
April 10 and May 27, but many U.S. troops were in the general area."
"Deputy Secretary of State Richard Armitage said it 'looks to me like
somehow the multinational force didn't stay on top of this.'

http://www.abcnews.go.com/WNT/story?id=204304&page=1

http://www.washingtontimes.com/national/20041028-122637-6257r.htm


The wonderful thing about the Web is that you can find "documented"
support for almost any position.

John

 

[Dbowey]

Guy wrote:

Paul Burridge wrote:

I don't understand why everyone is recommending a 100mhz scope!

It depends on what you want to do with it. I haven't dealt with
a clock rate higher than 20 MHz in years, and 99% of my work is
with clock rates of 1 MHz or less.

The OP posted that ham radio was an area of work/play where he anticipates use
for a scope. I wouldn't pop the case off of a modern transceiver with a scope
having less than a 100 MHz response. My last project was repairing a dog, R71A
and you simply can't do it without a *good* scope. I have barely needed
anything as slow as 20 MHz in a few years.

Don

 

[Joel Kolstad]

"Frithiof Andreas Jensen" <frithiof.jensen@diespammerdie.jensen.tdcadsl.dk>
wrote in message news:4180d8e9$0$174$edfadb0f@dread11.news.tele.dk...

the unused bits just happened to hold 160 Ascii chars.

What encoding is used for non-English languages? I occasionally see web
sites that mention a different number of characters for, e.g., Russian
messages...

 

[Chris Carlen]

John Larkin wrote:

On 27 Oct 2004 18:38:46 -0700, Winfield Hill
Winfield_member@newsguy.com> wrote:



Dozens of locked bunkers were not inspected for their contents at that
time, so any assertion now that they were empty then has to ring hollow.

"Pentagon officials admit the facility was not completely secured between
April 10 and May 27, but many U.S. troops were in the general area."
"Deputy Secretary of State Richard Armitage said it 'looks to me like
somehow the multinational force didn't stay on top of this.'



http://www.abcnews.go.com/WNT/story?id=204304&page=1

http://www.washingtontimes.com/national/20041028-122637-6257r.htm


The wonderful thing about the Web is that you can find "documented"
support for almost any position.

Which makes it effectively impossible for one who is not deluded by a
particular political ideology to get to the real truth. And those who
are deluded immediately believe those "facts" which are in accordance
with their ideology.

This does not bode well for our democracy. The "information age" is not
quite what its name would imply.


Good day!



--
_______________________________________________________________________
Christopher R. Carlen
Principal Laser/Optical Technologist
Sandia National Laboratories CA USA
crcarle@sandia.gov -- NOTE: Remove "BOGUS" from email address to reply.

 

[Joel Kolstad]

"Alexandre Heil Franca" <alexheil@hotmail.com> wrote in message
newsan.2004.10.28.14.06.14.402446@hotmail.com...

I am building a device that should include a USB-Host. As a USB-Host, it
should supply 5V x 500mA.

That's slightly wishful thinking. Download the USB spec from www.usb.org
.... you'll see that it specifies 4.75V for most nominal connections but can
get as low as 4.4V if you're at the end of a bunch of lower power hubs.
Transiently, it can drop to 4.07V. The upshot of all this is that powering
5V logic off of the USB bus directly is a little iffy... in actuality, it
wil usually work, but it is poor engineering practice and shouldn't be used
on commercial products.

Also, keep in mind that the 500mA number is what you'd typically 'expect'
from a full port USB port (either a motherboard port or a powered hub's
downstream port). Unpowered hub typically only provide 100mA to their
downstream ports. Your device isn't 'allowed' (by the spec) to pull more
than 100mA until it's been 'authorized' to do so by the host. Many cheap
high power devices violate this part of the spec, however, but again -- it's
a lot easier to get away with poor engineering design if you're somewhere in
Taiwan or China and your customer service department is non-existant or
e-mail only (and most of the time everything still works anyway).

I hasn't been able to find any reference about
the max. ripple for the power-bus.

I don't believe they specify 'ripple' -- just the maximum and minimum
nominal voltages and the minimum transient voltage. Hence, depending on how
you define 'ripple,' it could be well over a volt.

In reality I am not sure, if all clients must include a power supply it
self, or at least any kind a filter at the input of the power-bus. If any
of these options is true, I don't need to care about ripple. Does anyone
could point me any reference? Does anyone know how much it should be?

The most common power supply you see on USB peripherals is that they use a
3.3V logic (with a low dropout regulator) and don't have to worry about any
of this.

---Joel Kolstad

 

[Frithiof Andreas Jensen]

"Joel Kolstad" <JKolstad71HatesSpam@Yahoo.Com> skrev i en meddelelse
news:M46dnUI1-sgHhRzcRVn-qQ@comcast.com...

What encoding is used for non-English languages?

good question - the answer to which would be in one of the ITU standards
that I used to be bored to tears reading ;-)

There used to be a free, as in gratis, archive of GSM standards on the net
but I have forgotten the link. It can be dredged up, but not before Monday.

 

[CWatters]

"Alexandre Heil Franca" <alexheil@hotmail.com> wrote in message
newsan.2004.10.28.14.06.14.402446@hotmail.com...

Hi there!

I am building a device that should include a USB-Host. As a USB-Host, it
should supply 5V x 500mA. I hasn't been able to find any reference about
the max. ripple for the power-bus.

The full USB specifications are here.

http://www.usb.org/developers/docs/

It has to do a bit more than just supply 5V at 500mA.

The word "ripple" doesn't appear in the spec but it has to be included in
the voltage tollerance....

Quote from USB 2.0 Spec Chapter 7 Electrical section 7.3.2 page 178

Bus Timing/Electrical Characteristics
Parameter Symbol Conditions Min. Max. Units Supply Voltage:
High-power Port VBUS Note 2, Section 7.2.1 4.75 5.25 V
Low-power Port VBUS Note 2, Section 7.2.1 4.40 5.25 V
<continues>

However you also have to remain in spec when devices are
connected/disconnected..

See the following sections for more details....

7.2.4.1 Inrush Current Limiting
and
7.2.4.2 Dynamic Detach

Colin

 

[CWatters]

"Alexandre Heil Franca" <alexheil@hotmail.com> wrote in message
newsan.2004.10.28.14.06.14.402446@hotmail.com...

Hi there!

I am building a device that should include a USB-Host. As a USB-Host, it
should supply 5V x 500mA. I hasn't been able to find any reference about
the max. ripple for the power-bus.

The full USB specifications are here.

http://www.usb.org/developers/docs/

It has to do a bit more than just supply 5V at 500mA.

The word "ripple" doesn't appear in the spec but it has to be included in
the voltage tollerance....

Quote from USB 2.0 Spec Chapter 7 Electrical section 7.3.2 page 178

Bus Timing/Electrical Characteristics
Parameter Symbol Conditions Min. Max. Units Supply Voltage:
High-power Port VBUS Note 2, Section 7.2.1 4.75 5.25 V
Low-power Port VBUS Note 2, Section 7.2.1 4.40 5.25 V
<continues>

However you also have to remain in spec when devices are
connected/disconnected..

See the following sections for more details....

7.2.4.1 Inrush Current Limiting
and
7.2.4.2 Dynamic Detach

Colin

 

[Guy Macon]

Dbowey wrote:

The OP posted that ham radio was an area of work/play where
he anticipates use for a scope.

Ah. You will have to forgive me for missing some posts. I have
been finding myself looking at this newsgroup, seeing a huge
volume of off-topic posts, then moving on without reading anything.
This morning I looked at the last 1000 posts and killfiled every
participant who posted to a politics thread. What surprised me
was how many participants were left after I did that, and how
much more I am enjoying the newsgroup.

A shame, really. I have a lot of personal like for those who I just
killfiled, but alas, they had made the newsgroup unusable for me.

Getting back to the topic, I learned how to deal with higher
frequencies back when we only dreamed of 100 MHz scopes, but I
don't recommend learning those tricks to newly minted EEs - it
would be a better use of their time learning how to use a sliderule.

 

[Tam/WB2TT]

"Love a Sheep" <sheepshaggerx@yahoo.co.uk> wrote in message
news:264c4ea4.0410271421.5dd99fc6@posting.google.com...

Hi, I need an op-amp configured so that it acts in differential mode
(to subtract two signals) but with a single supply. It can be
ac-coupled.
I know how to do this with a dual power supply but I am unsure how to
do this with teh singel supply.

Thanks

If you use an op amp where the common mode range extends to 0, and the input
voltage is small enough, you don't need to do any of these things that
people are talking about.

Tam

 

[Steve]

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:Mqffd.34534$QJ3.7851@newssvr21.news.prodigy.com...

Hi Steve,

... As for the PCB layout itself, luckily we are doing a redesign so it
hopefully will be possible to accomodate whatever is required, whether it
is
an LC filter or a choke as you suggest, although we only have about one
quarter/third of one inch square to do it in (double-sided board.)


With that little space you won't likely be able to sqeeze any common
mode choke in there. I would try LC filtering since you said RC would
limit the slew rate too much. I am still wondering though why the slew
rate matters if the signal is digital audio. Of course you have to get
your 12 MHz through there.

Ok, since you said it's a coax here is suggestion number three: A coax
starts radiating stuff when both sides are mismatched. I guess the far
end is not under your control but the source side is. You could place a
series termination resistor equal to the Z of your coax in series with
the center conductor pin and make sure you drive that at low impedance.
The amplitude needs to be looked at, either you could bump it up by 6dB
or maybe there is a tolerance range where you have to fall into for
various mismatches at the far end. Anyway, now the coax sees a proper
termination at the source. This means that if something reflects at the
far end at least the reflctions from that will be dissipated and not
swing back and forth the line. This can reduce emissions quite
drastically.

To save money on EMC lab time see if you guys have a spectrum analyzer
or if one of your collegues owns a scanner radio with a signal strength
meter. If the noise was in the FM band an FM radio with a signal
strength indicator would work, too. Now you could hook up a simple
dipole using a short coax with a few clamp-on ferrites on either end and
place the radio and dipole ten feet away. Now try out your remedies and
watch the meter or bargraph on the radio. Try vertical and horizontal
polarization because the EMC lab will do that, too. Hint: If it's a
scanner switch to AM mode because you can hear changes in signal
strength better than straining your eyes on that meter. The other method
won't make you friends but I have done it. I took a lens off a lab lamp
and taped that in position in front of the analyzer screen (or maybe the
meter in your case). Talking about 101 uses for duct tape.

Try to get it down 20dB if you can. Open field measurements even at EMC
labs aren't always exactly repeatable. Too many variables. Good luck.

Regards, Joerg

http://www.analogconsultants.com

Many thanks for all that practical advice, Joerg. I'll give some of them a
go as soon I get a chance.

Steve

 

[Nicholas O. Lindan]

"Chris Carlen" <crcarle@BOGUS.sandia.gov> wrote

The wonderful thing about the Web is that you can find "documented"
support for almost any position.
Which makes it effectively impossible for one who is not deluded by a
particular political ideology to get to the real truth.

The closer one gets to the 'Real Truth' of a matter the more ambivalent
it becomes.

In the end it doesn't matter.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com

 

[legg]

On Thu, 28 Oct 2004 13:32:08 -0400, "Tam/WB2TT"
<t-tammaru@c0mca$t.net> wrote:

"Love a Sheep" <sheepshaggerx@yahoo.co.uk> wrote in message
news:264c4ea4.0410271421.5dd99fc6@posting.google.com...
Hi, I need an op-amp configured so that it acts in differential mode
(to subtract two signals) but with a single supply. It can be
ac-coupled.
I know how to do this with a dual power supply but I am unsure how to
do this with teh singel supply.

Thanks

If you use an op amp where the common mode range extends to 0, and the input
voltage is small enough, you don't need to do any of these things that
people are talking about.

Tam

......unless the expected resulting output would have to go negative

(ie any AC ground-referenced input signal)

sheesh

RL

 

[Frithiof Andreas Jensen]

"Guy Macon" <http://www.guymacon.com> skrev i en meddelelse
news:10o29bqfqau732c@corp.supernews.com...

What surprised me
was how many participants were left after I did that, and how
much more I am enjoying the newsgroup.

What surprises me is how much you like talking to yourself ;-)

 

[Julie]

Fred Bloggs wrote:

The Bush criminals in collaboration with Matt Drudge are starting to
make their move to disrupt the national elections. It is now clear they
*will be* voted OUT OF OFFICE, and the time to act is upon them. This
tape is a total fabrication. Apparently it was too much for the zealots
to forego discussion of "same sex marriage" in this supposed Al-Qaeda
terror production, and this will be the last straw.

The origins of this
tape will be traced back to the Bush administration, and they will be
removed from office:

Do you have any evidence of this that you can provide, or are you just stating
your personal unsubstantiated opinion?

 

[Jamie]

Steve Sands wrote:

Oh my God. Bush shot Kenny!

After all your foolishness here making a complete ass of yourself for
all these weeks you now want us to believe Drudge is part of this
story?

Oh ya after all his work in creating the site where the news gets
their news, Drudge is going to gamble it all on some fabricated tape?!

Drudge is no Dan Rather.

Why don't you just hang a sign on your ass saying "kick me" ?
then how could i see who i am talking too ? or was the intent to

kick out some teeth ?

 

[ChrisGibboGibson]

armando wrote:

Hello,

I am working on a science project that will pneumatically pound a
small nail into a piece of wood. I will be using a Basic Stamp to
control it. My question is what would you suggest for the actuator
and control mechanism (electrically controlled air valve?)? I have a
coleman bike/tire pump to 'power' the actuator. Any help will be much
appreciated. Please keep in mind that my budget is not huge for this
project.

Thank you in advance!

Have a google round the robot websites. Probably full of stuff like this.

My first thought would be a bike pump backwards for the actuator and a plastic
pipe with a crease in it, released by a solenoid for the control, fed from a
reservoir (a soda drink bottle?) pumped up with your bike pump. Cheap and
simple.

Gibbo.

 

[Joerg]

Maybe you can find some info about how rotary hammers work. I just bought a Bosch Bulldog rotary hammer. It has a hammer-only mode and from the lack of wrist pain after a 10 hour demolition project I assume it uses some kind of pneumatic action.

These things really rip. I was amazed that I could buy this tool for just over $200. With the variable speed it can hammer very gently but when fully pushing the trigger it sent a fist size chunk of concrete 10" up into the air.

Regards, Joerg

http://www.analogconsultants.com