magnetic field

[Ray L. Volts]

"Beano" <robininbkk@hotmail.com> wrote in message
news:1112956365.059615.78740@g14g2000cwa.googlegroups.com...

I understand the term 'Bandwidth' when used to refer to a range of
frequencies, eg Fmin to Fmax.
But I often hear the term used in place of 'frequency' and I wonder if
and when this should be done.
e.g. Should I refer to an oscilloscopes 'maximum frequency', or to
'it's bandwidth'.

You wouldn't use either term if you were to assume the same mindset Sencore
did when they wrote the manual for my trusty SC61 workhorse of an
analyzer -- they don't even call them scopes; how elitist can ya get?
Instead, you'd say, "frequency response is 60MHz; useable to 100MHz". Most
techs buy these scopes for the additional accuracy (and speed) afforded by
the separate LCD readout of the various waveform parameters. So, while
"useable to" may be technically correct -- and may have a psychological
marketing effect on some -- it's amusing, since the user won't get the same
level of accuracy out to that end of the bandwidth. Oops, I said bandwidth,
sorry Sencore.

 

[Peter Bennett]

On 8 Apr 2005 08:34:55 -0700, hartlyuk@yahoo.com (hartly) wrote:

"spudnuty" <spudnuty@lycos.com> wrote in message news:<1112854127.384074.47500@z14g2000cwz.googlegroups.com>...
Hmm is it just me but I don't seem to find an external power plug on
this camera and the manual doesn't mention an external supply. If so
you'll be opening the camera anyway to put your own in. Then you'll
figure out exactly how the batteries are wired. Most likely 6V.
Richard

Richard and others,
Thanks for replying and the info.
I won't open the camera as it seems to be glue sealed.
I will use dead batteries with wires soldered to the inner end to
touch the camera's terminals.I will have to cut a small slit in the
edge of the lid of the battery compartment to let the wires out
through.

Rather than using dead batteries, use wooden or plastic rod of the
right size - drive a screw into the end of the rod, and catch the wire
under it (or solder the wire to the screw).



--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

 

[Robert Baer]

kolotun@gmail.com wrote:

I would appreciate your opinions about the following device:

"Smart Tweezers LCR RCL RLC Meter Digital MultiMeter SMD"

I found on eBay. Looks like an interesting concept but is it as good as
the seller tells?

Without a link, to look and evaluate????

Forgeddit!

 

[Doug Warner]

Richard and others,
Thanks for replying and the info.
I won't open the camera as it seems to be glue sealed.
I will use dead batteries with wires soldered to the inner end to
touch the camera's terminals.I will have to cut a small slit in the
edge of the lid of the battery compartment to let the wires out
through.
The manufacturer included 4x1.5v.AAA new batts. (which lasted about
20 mins.!)
I'll have to use a sealed lead acid batt. of about 4Ah.in my jacket
pocket or rucksack as larger are too heavy.

Why bother with the external and it's wire. Just pop in a set of
high-capacity rechargeables, and it'll run for hours:
http://www.nimhbattery.com/mahapowerex-nimhbatteries-2300mAh-aa.htm


To reply, please remove one letter from each side of "@"
Spammers are VERMIN. Please kill them all.

 

[CWatters]

"Doug Warner" <dwarner22@ccharter.net> wrote in message
news:nhvf51h7sli8rkb8a630cro7t9ulga0qu2@4ax.com...

Why bother with the external and it's wire. Just pop in a set of
high-capacity rechargeables, and it'll run for hours:
http://www.nimhbattery.com/mahapowerex-nimhbatteries-2300mAh-aa.htm

They won't fit as the camera takes AAA not AA cells.

 

[Ray L. Volts]

"Beano" <robininbkk@hotmail.com> wrote in message
news:1113065434.056907.301490@l41g2000cwc.googlegroups.com...

OK, I'm going to attempt to answer my own question above.
Witout getting too finicky, 'frequency' should apply to a signal, and
'bandwidth' to a medium. Any better offers?

The very fact that you've decided to answer your own question (i.e.,
determine how you will apply the terms), validates what people have been
telling you (i.e., it's largely a matter of personal choice). As for the
standard definitions:

from the Illustrated Dictionary of Electronics (5th Ed.):

frequency:
"The rate at which a phenomenon is repeated. The basic unit of frequency is
the Hertz (Hz), which is 1 cycle per second."

bandwidth: "see bandpass, 1."
bandpass 1: "The frequency limits between which a device or circuit
transmits ac energy with negligible loss."


from Webster's Collegiate Dictionary:

frequency:
"1 : the fact or condition of occurring frequently
2 a : the number of times that a periodic function repeats the same sequence
of values during a unit variation of the independent variable; b : the
number of individuals in a single class when objects are classified
according to variations in a set of one or more specified attributes
3 : the number of repetitions of a periodic process in a unit of time: as a
: the number of complete alternations per second of an alternating current;
b : the number of complete oscillations per second of energy (as sound or
electromagnetic radiation) in the form of waves"

bandwidth:
"1 : a range within a band of wavelengths, frequencies, or energies;
especially : a range of radio frequencies which is occupied by a modulated
carrier wave, which is assigned to a service, or over which a device can
operate
2 : the capacity for data transfer of an electronic communications system
<graphics consume more bandwidth than text does>; especially : the maximum
data transfer rate of such a system"

 

[Rich Webb]

On 9 Apr 2005 12:10:08 -0700, soundweapon@cs.com wrote:

Classified US Government Technology

The United States government now has surveillance technology than can
electronically see and hear through walls.
[deletia maxima rantage]

Um, OK. Pretend this isn't just the effects of drinking too much Sterno.
The commercial possibilities of the technology in the building trades,
industrial monitoring and plant process control, medical imaging, et
cetera, et cetera are, ummm, significant. Do you really believe that if
something like you describe really existed, it wouldn't be in widespread
commercial use within, oh, about a day and a half?

Please Note: Postings on newsgroups of this message are being removed
possibly by the government. Hundreds of newsgroup postings of this
message have been removed, sometimes within a few hours of initial
postings. Please copy this information and repost it in any appropriate
newsgroup, including this one. Also, please send this information to
any federal, state, local law enforcement, congress person, and senator
you know of.

Sure thing. I'll also remember to ask about the 200 MPG carburetor
that's being suppressed by the oil industry. And the magic beans. Can't
forget the magic beans.

--
Rich Webb Norfolk, VA

 

[Robert Baer]

kolotun@gmail.com wrote:

Robert Baer wrote:

kolotun@gmail.com wrote:

I would appreciate your opinions about the following device:

"Smart Tweezers LCR RCL RLC Meter Digital MultiMeter SMD"

I found on eBay. Looks like an interesting concept but is it as

good as

the seller tells?


Without a link, to look and evaluate????
Forgeddit!


http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=25412&item=7506323975

1) For the size, Priority Mail Flat Rate is $3.85; the envelope could be

distorted more by adding padding. As long as one can fit something in
that envelope and seal it, there is no limit to the weight.
Theoretically, one could ship about 42 pounds of pure osmimum (the most
dense element known).
2) ?Five? digits? Forget it.
a) Impossible for capacitors and impractical as the best accuracy one
could possibly find in an SMD capacitor might be 5%. Stray capacitance
around the probe leads can add anything from 0.2pF to 5-10pF. The PCB,
the PCB traces, and all parts in parallel with the capacitor to be
?measured? can add another 2-20pF on strays alone.
b) Impossible for non-PCB resistors; maybe 3 digits for the low values
as the probe is *not* kelvin - and maybe 4 digits for higher values to a
few megs. If the resistors are on a PCB, then there are too many parts
that can be in parallel, and the reading can me orders of magnitude off.
c) Inductors: maybe 2 digits at best in a PCB environment. The stray
capacitances mentioned previously can royally mess up readings.
3) Parts sorting - Possible; 3 digits at most.
**
Now i see their specs; the best is 1%, which absolutely KILLs 5
digits and underscores my 3 digit statement above.
I see the hoopla concerning Ac waveforms, but one must note that
there is *no* specification concerning AC!

Good curiosity item, not too good (especially at the price) for
debugging an assembled PCB as most failures would be in the ICs after
useage.

 

[Gerhard]

kolotun@gmail.com schreef:

I would appreciate your opinions about the following device:

"Smart Tweezers LCR RCL RLC Meter Digital MultiMeter SMD"

I found on eBay. Looks like an interesting concept but is it as good as
the seller tells?

I bought one. It is a nice peace of equipment, except for the jog dial
button. Left and right movement are ok, but when pressing it the result
is completely unpredictable. Therefore it is impossible to set up the
instrument. And when you eventually get back to the measurement mode,
you don't know how it is set up.
I tried to contact the manufacturer, but got no response until now.

http://www.siborg.com/smarttweezers/ST_Canada_2.htm

Best regards,

Gerhard

 

[Gerhard]

kolotun@gmail.com schreef:

I would appreciate your opinions about the following device:

"Smart Tweezers LCR RCL RLC Meter Digital MultiMeter SMD"

I found on eBay. Looks like an interesting concept but is it as good as
the seller tells?

I bought one. It is a nice peace of equipment, except for the jog dial
button. Left and right movement are ok, but when pressing it the result
is completely unpredictable. Therefore it is impossible to set up the
instrument. And when you eventually get back to the measurement mode,
you don't know how it is set up.
I tried to contact the manufacturer, but got no response until now.

http://www.siborg.com/smarttweezers/ST_Canada_2.htm

Best regards,

Gerhard

 

[Glenn Ashmore]

Check out this http://members.cox.net/berniekm/super.html

Looks like you could build one for about $50. With a little immagination
you could even mount a tweezer on the front end.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

<kolotun@gmail.com> wrote in message
news:1112970906.876899.71750@g14g2000cwa.googlegroups.com...

I would appreciate your opinions about the following device:

"Smart Tweezers LCR RCL RLC Meter Digital MultiMeter SMD"

I found on eBay. Looks like an interesting concept but is it as good as
the seller tells?

 

[John Woodgate]

I read in sci.electronics.design that Gerhard
<gv#eerden##spamp@remove##tref.nl> wrote (in
<d3b5a8$9ee$2@reader10.wxs.nl&gt about 'Opinions about Smart Tweezers
Handheld RCL Meter', on Sun, 10 Apr 2005:

bought one. It is a nice peace of equipment,

That's good...

except for the jog dial button.

..... but that would make me war-y.
--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Michael A. Terrell]

Robert Baer wrote:

a) Impossible for capacitors and impractical as the best accuracy one
could possibly find in an SMD capacitor might be 5%. Stray capacitance
around the probe leads can add anything from 0.2pF to 5-10pF. The PCB,
the PCB traces, and all parts in parallel with the capacitor to be
?measured? can add another 2-20pF on strays alone.

No better than 5%? Then where did all the 1% 100pf SMD caps come
from I used in Salen Key filters at Microdyne? The design is about
eight years old and they were off the shelf then. I used a set of test
tweezers with one of our digital capacitance meters and could not only
zero out the probe, but read the caps properly.


--
Former professional electron wrangler.

Michael A. Terrell
Central Florida

 

[Michael A. Terrell]

Glenn Ashmore wrote:

Check out this http://members.cox.net/berniekm/super.html

Looks like you could build one for about $50. With a little immagination
you could even mount a tweezer on the front end.

--
Glenn Ashmore

Another impossible to read web page Dark green on a black
background? Are they crazy?

--
Former professional electron wrangler.

Michael A. Terrell
Central Florida

 

[Don Pearce]

On Sun, 10 Apr 2005 14:46:14 GMT, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

Glenn Ashmore wrote:

Check out this http://members.cox.net/berniekm/super.html

Looks like you could build one for about $50. With a little immagination
you could even mount a tweezer on the front end.

--
Glenn Ashmore


Another impossible to read web page Dark green on a black
background? Are they crazy?

Really? I get a medium green on a dark background, and it reads rather
easily. Check your brightness and contrast - they sound misadjusted.

d

Pearce Consulting
http://www.pearce.uk.com

 

[Michael A. Terrell]

Don Pearce wrote:

On Sun, 10 Apr 2005 14:46:14 GMT, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

Glenn Ashmore wrote:

Check out this http://members.cox.net/berniekm/super.html

Looks like you could build one for about $50. With a little immagination
you could even mount a tweezer on the front end.

--
Glenn Ashmore


Another impossible to read web page Dark green on a black
background? Are they crazy?

Really? I get a medium green on a dark background, and it reads rather
easily. Check your brightness and contrast - they sound misadjusted.

d

Pearce Consulting
http://www.pearce.uk.com

Its as bright as I can get it without retrace lines.

--
Former professional electron wrangler.

Michael A. Terrell
Central Florida

 

[Charles Schuler]

"Beano" <robininbkk@hotmail.com> wrote in message
news:1113065434.056907.301490@l41g2000cwc.googlegroups.com...

OK, I'm going to attempt to answer my own question above.
Witout getting too finicky, 'frequency' should apply to a signal, and
'bandwidth' to a medium. Any better offers?

Better? Don't know, but here goes. A single frequency is useless when one
needs to convey intelligence (information). A frequency source must be
modulated to carry information and that process adds sidebands (frequencies
above and below the single frequency). The more information or intelligence
one must add (assuming time is valuable and thus the data rate has to be
reasonable) the wider the bandwidth. So, bandwidth is a resource, because
as one uses it up there is not enough left for other purposes. Frequency is
just the center or average of the bandwidth.

Does that help you? Yes? No?

 

[Glenn]

kolotun@gmail.com wrote:

I would appreciate your opinions about the following device:

"Smart Tweezers LCR RCL RLC Meter Digital MultiMeter SMD"

I found on eBay. Looks like an interesting concept but is it as good as
the seller tells?

I bought one too.

I agree with the previous owner that the jog dial is a bit confusing but
I think I did manage to figure it out and the unit seems fine for
identifying all those SMDs laying around under the stereomicroscope that
would otherwise get tossed because its too much trouble to figure out
what they are. And that's even with a vector network analyzer and
benchtop DMM handy...

The Voltage/Plot mode is probably not of any real use. It's also a pain
to have to mess with the slide switch to get to it. If I'm doing
something in-circuit I'll use a benchtop DMM anyway. However the
auto-range auto-select does seem to do a reasonable job at identify both
the type and value of the component. Having it all in a tweezer is
actually fairly useful. The alternative is to try to get a part to hold
still while you get two probes from a meter on it.

The Tweezers are not entirely useless on installed components, but of
course one has to know hwat the circuit is to know how to interperet the
results. I think their forte is loose SMDs.


So, all in all, my assessment is that it is a little pricey when you
consider the functionality apart from the integration, and perhaps a
little bit so, even then, but that it does prove to be a useful tool.
I've only used mine a modest amount so far but don't regret buying it.

Glenn

 

[Robert Baer]

Glenn Ashmore wrote:

Check out this http://members.cox.net/berniekm/super.html

Looks like you could build one for about $50. With a little immagination
you could even mount a tweezer on the front end.

That Mondo Technology Super Probe is a far better instrument for the

money, and ther is no hype (no 5 digit display for a 3 digit device).

 

[Robert Baer]

Michael A. Terrell wrote:

Robert Baer wrote:

a) Impossible for capacitors and impractical as the best accuracy one
could possibly find in an SMD capacitor might be 5%. Stray capacitance
around the probe leads can add anything from 0.2pF to 5-10pF. The PCB,
the PCB traces, and all parts in parallel with the capacitor to be
?measured? can add another 2-20pF on strays alone.


No better than 5%? Then where did all the 1% 100pf SMD caps come
from I used in Salen Key filters at Microdyne? The design is about
eight years old and they were off the shelf then. I used a set of test
tweezers with one of our digital capacitance meters and could not only
zero out the probe, but read the caps properly.


Must have been specialty parts at a specialty price.

Ordinary capacitors run from 5% to 20%, and the few 2% caps are wound
plastics.
I dare say that the only SMD caps are ceramics, meaning that the
accuracy is limited by the construction and physics of construction.
Green ceramic caps change size and shape when fired; cannot get
around that.
Now, one *could* test to a tight spec; bin the passes for hi $ and
the failures for regular sales.
BTW, do you know the temp curves for X5R, Y5V, etc???