high impedance capacitive cable, what is it

[Fibo]

hello, I heard somebody talking about a type of cable the other day
and I can't find any information on it... does this make sense to
anybody:

I was doing a continuity check (aka ohming out, ringing out...etc etc)
on a db15 cable with all the pins connected straight through the
cable... and my multimeter was showing very high (open) resistance on
all the pins... then someone said something that was something like
this:

"maybe it's a capacitive type cable where it sends/recieves pulses....
then it would make sense that you're seeing such high resistance"

- I've tried googling to find out what this person was talking about,
but have found anything.... I was wondering if anyone in here knew
what this person may have been talking about?

Thanks,
Fibo

 

[Bo Vance]

Fibo wrote:

hello, I heard somebody talking about a type of cable the other day
and I can't find any information on it... does this make sense to
anybody:

I was doing a continuity check (aka ohming out, ringing out...etc etc)
on a db15 cable with all the pins connected straight through the
cable... and my multimeter was showing very high (open) resistance on
all the pins... then someone said something that was something like
this:

"maybe it's a capacitive type cable where it sends/recieves pulses....
then it would make sense that you're seeing such high resistance"

- I've tried googling to find out what this person was talking about,
but have found anything.... I was wondering if anyone in here knew
what this person may have been talking about?

Thanks,
Fibo

Maybe filtered D-Sub adapters?
These from Harting:
http://tinyurl.com/3huovg

 

[Steve]

"Fibo" <panfilero@hotmail.com> wrote in message
news:e138971c-b6c7-4cb8-9293-e78d2c67e790@y79g2000hsa.googlegroups.com...

hello, I heard somebody talking about a type of cable the other day
and I can't find any information on it... does this make sense to
anybody:

I was doing a continuity check (aka ohming out, ringing out...etc etc)
on a db15 cable with all the pins connected straight through the
cable... and my multimeter was showing very high (open) resistance on
all the pins... then someone said something that was something like
this:

"maybe it's a capacitive type cable where it sends/recieves pulses....
then it would make sense that you're seeing such high resistance"

- I've tried googling to find out what this person was talking about,
but have found anything.... I was wondering if anyone in here knew
what this person may have been talking about?

Thanks,
Fibo

Ignore the capacitive cable comment. There's no such thing. Those fast edges
would experience all kinds of frequency dependent delay and the cable would
not have a constant characteristic impedance to support signal integrity.

Are you sure your meter leads are OK? Are the pins (or leads) corroded or
oxidized?

Steve


** Posted from http://www.teranews.com **

 

[Bob Eld]

"Fibo" <panfilero@hotmail.com> wrote in message
news:e138971c-b6c7-4cb8-9293-e78d2c67e790@y79g2000hsa.googlegroups.com...

hello, I heard somebody talking about a type of cable the other day
and I can't find any information on it... does this make sense to
anybody:

I was doing a continuity check (aka ohming out, ringing out...etc etc)
on a db15 cable with all the pins connected straight through the
cable... and my multimeter was showing very high (open) resistance on
all the pins... then someone said something that was something like
this:

"maybe it's a capacitive type cable where it sends/recieves pulses....
then it would make sense that you're seeing such high resistance"

- I've tried googling to find out what this person was talking about,
but have found anything.... I was wondering if anyone in here knew
what this person may have been talking about?

Thanks,
Fibo

All metalic cables, connectors and conductors have low ohmic resistance
regardless of their impedance. If you do not have low ohm continuity,
something is wrong, pin confusion, broken wires, un-crimped pins, corroded
pins, mis-wired, bad meter, etc.

 

[John Fields]

On Tue, 7 Oct 2008 06:13:35 -0700 (PDT), Fibo <panfilero@hotmail.com>
wrote:

hello, I heard somebody talking about a type of cable the other day
and I can't find any information on it... does this make sense to
anybody:

I was doing a continuity check (aka ohming out, ringing out...etc etc)
on a db15 cable with all the pins connected straight through the
cable... and my multimeter was showing very high (open) resistance on
all the pins... then someone said something that was something like
this:

"maybe it's a capacitive type cable where it sends/recieves pulses....
then it would make sense that you're seeing such high resistance"

- I've tried googling to find out what this person was talking about,
but have found anything.... I was wondering if anyone in here knew
what this person may have been talking about?

---
He was talking nonsense.

Some of the possibilities are:

1. You've got your DMM set on VOLTS or AMPS instead of OHMS or
CONTINUITY.

2. Your meter's OHMS and/or CONTINUITY function is broken

3. One or both of your test leads is broken.

4. All of the cable's conductors are open.

5. The cable is miswired and you haven't checked a pin on one end
against all the pins on the other end.

JF

 

[Fibo]

On Oct 7, 9:37 am, "Steve" <sNodots.bu...@Nodots.jomega.com> wrote:

"Fibo" <panfil...@hotmail.com> wrote in message

news:e138971c-b6c7-4cb8-9293-e78d2c67e790@y79g2000hsa.googlegroups.com...



hello, I heard somebody talking about a type of cable the other day
and I can't find any information on it... does this make sense to
anybody:

I was doing a continuity check (aka ohming out, ringing out...etc etc)
on a db15 cable with all the pins connected straight through the
cable... and my multimeter was showing very high (open) resistance on
all the pins... then someone said something that was something like
this:

"maybe it's a capacitive type cable where it sends/recieves pulses....
then it would make sense that you're seeing such high resistance"

- I've tried googling to find out what this person was talking about,
but have found anything.... I was wondering if anyone in here knew
what this person may have been talking about?

Thanks,
Fibo

Ignore the capacitive cable comment. There's no such thing. Those fast edges
would experience all kinds of frequency dependent delay and the cable would
not have a constant characteristic impedance to support signal integrity.

Are you sure your meter leads are OK? Are the pins (or leads) corroded or
oxidized?

Steve

** Posted fromhttp://www.teranews.com**

Yeah, my cable and meter are fine... my cable is just a regular cable,
I haven't opened her up yet, but I imagine there's nothing connected
in it... but that's no problem... my real confusion/question was....
trying to figure out what this person was talking about... because
I've never heard of anything like that... a capacitance based cable
that's used for transmitting pulses and uses regular DB9 (or 15 or
whatever) type of connectors.... I was just wondering if that made
sense to anyone in here...

 

[Fibo]

On Oct 7, 9:50 am, John Fields <jfie...@austininstruments.com> wrote:

On Tue, 7 Oct 2008 06:13:35 -0700 (PDT), Fibo <panfil...@hotmail.com
wrote:



hello, I heard somebody talking about a type of cable the other day
and I can't find any information on it... does this make sense to
anybody:

I was doing a continuity check (aka ohming out, ringing out...etc etc)
on a db15 cable with all the pins connected straight through the
cable... and my multimeter was showing very high (open) resistance on
all the pins... then someone said something that was something like
this:

"maybe it's a capacitive type cable where it sends/recieves pulses....
then it would make sense that you're seeing such high resistance"

- I've tried googling to find out what this person was talking about,
but have found anything.... I was wondering if anyone in here knew
what this person may have been talking about?

---
He was talking nonsense.

Some of the possibilities are:

1. You've got your DMM set on VOLTS or AMPS instead of OHMS or
   CONTINUITY.

2. Your meter's OHMS and/or CONTINUITY function is broken

3. One or both of your test leads is broken.

4. All of the cable's conductors are open.

5. The cable is miswired and you haven't checked a pin on one end
   against all the pins on the other end.

JF

ok... good... so there's no pulse sensing type of cable that wouldn't
register a low impedance.... I'm glad to hear that, cause I didn't
know what in the world he was referring to

much thanks

 

[Anton Erasmus]

On Tue, 7 Oct 2008 06:13:35 -0700 (PDT), Fibo <panfilero@hotmail.com>
wrote:

hello, I heard somebody talking about a type of cable the other day
and I can't find any information on it... does this make sense to
anybody:

I was doing a continuity check (aka ohming out, ringing out...etc etc)
on a db15 cable with all the pins connected straight through the
cable... and my multimeter was showing very high (open) resistance on
all the pins... then someone said something that was something like
this:

"maybe it's a capacitive type cable where it sends/recieves pulses....
then it would make sense that you're seeing such high resistance"

- I've tried googling to find out what this person was talking about,
but have found anything.... I was wondering if anyone in here knew
what this person may have been talking about?

The only cable I have ever seen where I got odd results, turned out to
be thermo-couple cable. The 2 conductors are made from different
metals. I did not know what it was and used it for my supply. My
circuit did not work, and it turned out I had quite a big voltage drop
over a fairly short piece of this cable.

Regards
Anton Erasmus

 

[Glenn Mřller-Holst]

Fibo wrote:

hello, I heard somebody talking about a type of cable the other day
and I can't find any information on it... does this make sense to
anybody:

I was doing a continuity check (aka ohming out, ringing out...etc etc)
on a db15 cable with all the pins connected straight through the
cable... and my multimeter was showing very high (open) resistance on
all the pins... then someone said something that was something like
this:

"maybe it's a capacitive type cable where it sends/recieves pulses....
then it would make sense that you're seeing such high resistance"

- I've tried googling to find out what this person was talking about,
but have found anything.... I was wondering if anyone in here knew
what this person may have been talking about?

Thanks,
Fibo

Hi Fibo

Could he have meant something like this?:

Fluke PM9080/001 *Optically* *Isolated* RS232 Adapter/Cable:
http://www.globaltestsupply.com/test_equipment/Fluke_PM9080_001_Optically_Isolated_RS232_Adapter_Cable.cfm

/Glenn

 

[Robert Baer]

Fibo wrote:

hello, I heard somebody talking about a type of cable the other day
and I can't find any information on it... does this make sense to
anybody:

I was doing a continuity check (aka ohming out, ringing out...etc etc)
on a db15 cable with all the pins connected straight through the
cable... and my multimeter was showing very high (open) resistance on
all the pins... then someone said something that was something like
this:

"maybe it's a capacitive type cable where it sends/recieves pulses....
then it would make sense that you're seeing such high resistance"

- I've tried googling to find out what this person was talking about,
but have found anything.... I was wondering if anyone in here knew
what this person may have been talking about?

Thanks,
Fibo
Stupid answer.

 

[Robert Baer]

Bob Eld wrote:

"Fibo" <panfilero@hotmail.com> wrote in message
news:e138971c-b6c7-4cb8-9293-e78d2c67e790@y79g2000hsa.googlegroups.com...

hello, I heard somebody talking about a type of cable the other day
and I can't find any information on it... does this make sense to
anybody:

I was doing a continuity check (aka ohming out, ringing out...etc etc)
on a db15 cable with all the pins connected straight through the
cable... and my multimeter was showing very high (open) resistance on
all the pins... then someone said something that was something like
this:

"maybe it's a capacitive type cable where it sends/recieves pulses....
then it would make sense that you're seeing such high resistance"

- I've tried googling to find out what this person was talking about,
but have found anything.... I was wondering if anyone in here knew
what this person may have been talking about?

Thanks,
Fibo


All metalic cables, connectors and conductors have low ohmic resistance
regardless of their impedance. If you do not have low ohm continuity,
something is wrong, pin confusion, broken wires, un-crimped pins, corroded
pins, mis-wired, bad meter, etc.


Check; most likely connection problems between meter leads and cable

connector(s).

 

[Robert Baer]

Fibo wrote:

On Oct 7, 9:37 am, "Steve" <sNodots.bu...@Nodots.jomega.com> wrote:

"Fibo" <panfil...@hotmail.com> wrote in message

news:e138971c-b6c7-4cb8-9293-e78d2c67e790@y79g2000hsa.googlegroups.com...




hello, I heard somebody talking about a type of cable the other day
and I can't find any information on it... does this make sense to
anybody:

I was doing a continuity check (aka ohming out, ringing out...etc etc)
on a db15 cable with all the pins connected straight through the
cable... and my multimeter was showing very high (open) resistance on
all the pins... then someone said something that was something like
this:

"maybe it's a capacitive type cable where it sends/recieves pulses....
then it would make sense that you're seeing such high resistance"

- I've tried googling to find out what this person was talking about,
but have found anything.... I was wondering if anyone in here knew
what this person may have been talking about?

Thanks,
Fibo

Ignore the capacitive cable comment. There's no such thing. Those fast edges
would experience all kinds of frequency dependent delay and the cable would
not have a constant characteristic impedance to support signal integrity.

Are you sure your meter leads are OK? Are the pins (or leads) corroded or
oxidized?

Steve

** Posted fromhttp://www.teranews.com**


Yeah, my cable and meter are fine... my cable is just a regular cable,
I haven't opened her up yet, but I imagine there's nothing connected
in it... but that's no problem... my real confusion/question was....
trying to figure out what this person was talking about... because
I've never heard of anything like that... a capacitance based cable
that's used for transmitting pulses and uses regular DB9 (or 15 or
whatever) type of connectors.... I was just wondering if that made
sense to anyone in here...
No such thing, and zero reason to be made.

 

[Jasen Betts]

On 2008-10-07, Fibo <panfilero@hotmail.com> wrote:

I was doing a continuity check (aka ohming out, ringing out...etc etc)
on a db15 cable with all the pins connected straight through the
cable... and my multimeter was showing very high (open) resistance on
all the pins... then someone said something that was something like
this:

either a fault with your multimeter or that cable is broken.
(or possibly wired differently)

"maybe it's a capacitive type cable where it sends/recieves pulses....
then it would make sense that you're seeing such high resistance"

sounds spurious to me, I don't think VGA signals will pass well thrugh
a capacitor.

although a capacitive cable can be used with RF signals to isolate
ground loops.

Bye.
Jasen

 

[Bob Masta]

On Tue, 7 Oct 2008 06:13:35 -0700 (PDT), Fibo
<panfilero@hotmail.com> wrote:

hello, I heard somebody talking about a type of cable the other day
and I can't find any information on it... does this make sense to
anybody:

I was doing a continuity check (aka ohming out, ringing out...etc etc)
on a db15 cable with all the pins connected straight through the
cable... and my multimeter was showing very high (open) resistance on
all the pins.
snip

Double-check the pin numbering scheme. If *all*
the pins are showing open, that makes me think
that you may be using the mirror image of the
proper scheme on one end.

Best regards,


Bob Masta

DAQARTA v4.50
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
FREE Signal Generator
Science with your sound card!

 

[Fibo]

On Oct 8, 4:49 am, Jasen Betts <ja...@xnet.co.nz> wrote:

On 2008-10-07, Fibo <panfil...@hotmail.com> wrote:

I was doing a continuity check (aka ohming out, ringing out...etc etc)
on a db15 cable with all the pins connected straight through the
cable... and my multimeter was showing very high (open) resistance on
all the pins... then someone said something that was something like
this:

either a fault with your multimeter or that cable is broken.
(or possibly wired differently)

"maybe it's a capacitive type cable where it sends/recieves pulses....
then it would make sense that you're seeing such high resistance"

sounds spurious to me, I don't think VGA signals will pass well thrugh
a capacitor.

although a capacitive cable can be used with RF signals to isolate
ground loops.

Bye.
   Jasen

"Hi Fibo

Could he have meant something like this?:

Fluke PM9080/001 *Optically* *Isolated* RS232 Adapter/Cable: "

- woah, what is this thing used for? I've never seen one of these


"although a capacitive cable can be used with RF signals to isolate
ground loops."

- So there is such a thing?

 

On Oct 7, 10:37 am, "Steve" <sNodots.bu...@Nodots.jomega.com> wrote:

Ignore the capacitive cable comment. There's no such thing. Those fast edges
would experience all kinds of frequency dependent delay and the cable would
not have a constant characteristic impedance to support signal integrity.

I would grant that it is probably not a cable with series capacitance,
but such a thing is neither impossible nor useless.

If you have a moderately fast signaling scheme, digital or analog,
that does not depend on any low frequency component or DC offset, it
may be desirable to have A/C coupled interconnect.

Unshielded twisted pair Ethernet is a good example. Normally the DC
blocking is done by transformers, but if you are just fooling around
on a lab bench for fun it will often more or less work with series
caps instead.

Usually I'd think the DC coupling components would be found just
inboard of the connector, not in the cable. So I don't really think
that is what is happening here, but it's not impossible.

 

[Jasen Betts]

On 2008-10-08, Fibo <panfilero@hotmail.com> wrote:

Could he have meant something like this?:

Fluke PM9080/001 *Optically* *Isolated* RS232 Adapter/Cable: "

- woah, what is this thing used for? I've never seen one of these

prolly for connecting a multimeter with serial output to an earthed
device (like an ordinary pc)

"although a capacitive cable can be used with RF signals to isolate
ground loops."

- So there is such a thing?

I've seen adaptors with TV antenna style plugs, there's no reason why
the same circuit couldn't be built into a cable.

Bye.
Jasen

 

[Not Really Me]

"Fibo" <panfilero@hotmail.com> wrote in message
news:e138971c-b6c7-4cb8-9293-e78d2c67e790@y79g2000hsa.googlegroups.com...

hello, I heard somebody talking about a type of cable the other day
and I can't find any information on it... does this make sense to
anybody:
snip

I think it's used to connect a flux capacitor to a refurbigated framagammit.
Only used on DeLorean's, so it's very hard to find.

Scott

 

[Apostrophe Police]

On Thu, 09 Oct 2008 09:43:51 -0600, Not Really Me wrote:

I think it's used to connect a flux capacitor to a refurbigated framagammit.
Only used on DeLorean's, so it's very hard to find.

Used on Delorean's what?
--
Rich Grise, Self-Appointed Chief,
Apostrophe Police

 

On Thu, 09 Oct 2008 21:15:54 GMT, Apostrophe Police
<apopol@example.net> wrote:

On Thu, 09 Oct 2008 09:43:51 -0600, Not Really Me wrote:

I think it's used to connect a flux capacitor to a refurbigated framagammit.
Only used on DeLorean's, so it's very hard to find.


Used on Delorean's what?

Time travel system.
--
ArarghMail810 at [drop the 'http://www.' from ->] http://www.arargh.com
BCET Basic Compiler Page: http://www.arargh.com/basic/index.html

To reply by email, remove the extra stuff from the reply address.