Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

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

Jim Thompson wrote:
Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?

...Jim Thompson
To both questions, measure it?
the cable for example,connect to a scope(multimeter),
feed it from a source(there a re nice tonegenerator programs
for xp and soundcard),and compare voltages, then calculate
capacity.
Same method for the piezo.
Or check out an internetshop for them, and see if they
have technical specs.
Also, anumber of multimeters have

On Sun, 20 Feb 2011 01:53:05 +0100, Sjouke Burry
wrote:

Jim Thompson wrote:
Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?

...Jim Thompson
To both questions, measure it?
the cable for example,connect to a scope(multimeter),
feed it from a source(there a re nice tonegenerator programs
for xp and soundcard),and compare voltages, then calculate
capacity.
Same method for the piezo.
Or check out an internetshop for them, and see if they
have technical specs.
Also, anumber of multimeters have

I don't have a signal generator, but do have a multimeter and a scope.

I guess I can measure risetime of the final circuit and then beef up
as needed.

Amazing how many ridiculous answers you can get here :-(

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Remember: Once you go over the hill, you pick up speed

On Sat, 19 Feb 2011 17:33:33 -0700, the renowned Jim Thompson
wrote:

Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Probably a few tens of nF for a 20mm 'bender' disk (which will be
larger when mounted on the metal backing).

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?

...Jim Thompson

10-20pF per foot comes to mind.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

"Jim Thompson" wrote
in message ...
Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?


Some call the cable Cat1, but TIA never catagorized anything below Cat3.
So 100ohm would be a good guess with out looking up the mfg specs.

Heres the Beldin wire data sheet..
https://edeskv2.belden.com/Products/index.cfm?event=printPrev&pnum=STBLK22&ut=english

Some vague references to 40 - 50nF / km for 24-26awg TP wire, on the
telecom sites.
http://books.google.com/books?id=K4ribVEOhSAC&pg=PA806&lpg=PA806&dq=50nF/mile&source=bl&ots=JT5nKQ8tHC&sig=N6Fd4xlipKs2f1He W327W8tlRKg&hl=en&ei=DHZgTcmNM8eugQfjx-HmAg&sa=X&oi=book_result&ct=result&resnum=1&ved=0C BMQ6AEwAA#v=onepage&q&f=false


Cheers

"Jim Thompson" wrote
in message ...
Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?


Some call the cable Cat1, but TIA never catagorized anything below Cat3.
So 100ohm would be a good guess with out looking up the mfg specs.

Heres the Beldin wire data sheet..
https://edeskv2.belden.com/Products/index.cfm?event=printPrev&pnum=STBLK22&ut=english

Some vague references to 40 - 50nF / km for 24-26awg TP wire, on the
telecom sites.
http://books.google.com/books?id=K4ribVEOhSAC&pg=PA806&lpg=PA806&dq=50nF/mile&source=bl&ots=JT5nKQ8tHC&sig=N6Fd4xlipKs2f1He W327W8tlRKg&hl=en&ei=DHZgTcmNM8eugQfjx-HmAg&sa=X&oi=book_result&ct=result&resnum=1&ved=0C BMQ6AEwAA#v=onepage&q&f=false


Cheers

On Sat, 19 Feb 2011 20:50:56 -0500, Spehro Pefhany
wrote:

On Sat, 19 Feb 2011 17:33:33 -0700, the renowned Jim Thompson
wrote:

Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Probably a few tens of nF for a 20mm 'bender' disk (which will be
larger when mounted on the metal backing).

Gads!


Likewise, how much capacitance in around 100' of typical telephone
twisted pair?

...Jim Thompson

10-20pF per foot comes to mind.


Best regards,
Spehro Pefhany

Thanks!

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Remember: Once you go over the hill, you pick up speed

"Martin Riddle" wrote in message
...


"Jim Thompson"
wrote in message ...
Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?


Some call the cable Cat1, but TIA never catagorized anything below
Cat3.
So 100ohm would be a good guess with out looking up the mfg specs.

Heres the Beldin wire data sheet..
https://edeskv2.belden.com/Products/index.cfm?event=printPrev&pnum=STBLK22&ut=english

Some vague references to 40 - 50nF / km for 24-26awg TP wire, on the
telecom sites.
http://books.google.com/books?id=K4ribVEOhSAC&pg=PA806&lpg=PA806&dq=50nF/mile&source=bl&ots=JT5nKQ8tHC&sig=N6Fd4xlipKs2f1He W327W8tlRKg&hl=en&ei=DHZgTcmNM8eugQfjx-HmAg&sa=X&oi=book_result&ct=result&resnum=1&ved=0C BMQ6AEwAA#v=onepage&q&f=false


Cheers




1 foot of the RS variety telephone 4-cond cable measured 23pF

Cheers

"Martin Riddle" wrote in message
...


"Jim Thompson"
wrote in message ...
Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?


Some call the cable Cat1, but TIA never catagorized anything below
Cat3.
So 100ohm would be a good guess with out looking up the mfg specs.

Heres the Beldin wire data sheet..
https://edeskv2.belden.com/Products/index.cfm?event=printPrev&pnum=STBLK22&ut=english

Some vague references to 40 - 50nF / km for 24-26awg TP wire, on the
telecom sites.
http://books.google.com/books?id=K4ribVEOhSAC&pg=PA806&lpg=PA806&dq=50nF/mile&source=bl&ots=JT5nKQ8tHC&sig=N6Fd4xlipKs2f1He W327W8tlRKg&hl=en&ei=DHZgTcmNM8eugQfjx-HmAg&sa=X&oi=book_result&ct=result&resnum=1&ved=0C BMQ6AEwAA#v=onepage&q&f=false


Cheers




1 foot of the RS variety telephone 4-cond cable measured 23pF

Cheers

On Sat, 19 Feb 2011 21:48:35 -0500, "Martin Riddle"
wrote:



"Martin Riddle" wrote in message
...


"Jim Thompson"
wrote in message ...
Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?


Some call the cable Cat1, but TIA never catagorized anything below
Cat3.
So 100ohm would be a good guess with out looking up the mfg specs.

Heres the Beldin wire data sheet..
https://edeskv2.belden.com/Products/index.cfm?event=printPrev&pnum=STBLK22&ut=english

Some vague references to 40 - 50nF / km for 24-26awg TP wire, on the
telecom sites.
http://books.google.com/books?id=K4ribVEOhSAC&pg=PA806&lpg=PA806&dq=50nF/mile&source=bl&ots=JT5nKQ8tHC&sig=N6Fd4xlipKs2f1He W327W8tlRKg&hl=en&ei=DHZgTcmNM8eugQfjx-HmAg&sa=X&oi=book_result&ct=result&resnum=1&ved=0C BMQ6AEwAA#v=onepage&q&f=false


Cheers




1 foot of the RS variety telephone 4-cond cable measured 23pF

Cheers


Thanks, Martin!

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Remember: Once you go over the hill, you pick up speed

Sjouke Burry wrote:
Jim Thompson wrote:
Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?

To both questions, measure it?
the cable for example,connect to a scope(multimeter),
feed it from a source(there a re nice tonegenerator programs
for xp and soundcard),and compare voltages, then calculate
capacity.
Same method for the piezo.
Or check out an internetshop for them, and see if they
have technical specs.
Also, anumber of multimeters have

JT doesn't know how to measure anything. All he does is make analog
chip masks and **** and moan and threaten violence on everyone who
isn't in his little self-aggrandizing political mutual admiration
society.

Hope This Helps!
Rich

On 2/19/2011 6:33 PM, Jim Thompson wrote:
Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?

...Jim Thompson

I just measured the only piezo disk I have, a .75 inch one. It measures
20 nF.

Cheers,
John

On 2/19/2011 10:29 PM, John - KD5YI wrote:
On 2/19/2011 6:33 PM, Jim Thompson wrote:
Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?

...Jim Thompson

I just measured the only piezo disk I have, a .75 inch one. It measures
20 nF.

Cheers,
John

Oops! I found a .9 inch disk. Measures 24 nF.

John - KD5YI wrote:
On 2/19/2011 6:33 PM, Jim Thompson wrote:

Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?

...Jim Thompson


I just measured the only piezo disk I have, a .75 inch one. It measures
20 nF.

Cheers,
John
I would be willing to bet if you were to use several different model
instruments to measure that, you won't get inconsistent readings.. I
would think the applied energy from the instrument would cause a
piezoelectric (mechanical change) effect there by giving you different
readings from one to another..

Just a thought.

Jamie

On Sun, 20 Feb 2011 10:00:12 -0500, Jamie
t wrote:

John - KD5YI wrote:
On 2/19/2011 6:33 PM, Jim Thompson wrote:

Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?

...Jim Thompson


I just measured the only piezo disk I have, a .75 inch one. It measures
20 nF.

Cheers,
John
I would be willing to bet if you were to use several different model
instruments to measure that, you won't get inconsistent readings.. I
would think the applied energy from the instrument would cause a
piezoelectric (mechanical change) effect there by giving you different
readings from one to another..

---
Then you _would_ get inconsistent readings.

---
JF

John Fields wrote:

On Sun, 20 Feb 2011 10:00:12 -0500, Jamie
t wrote:


John - KD5YI wrote:

On 2/19/2011 6:33 PM, Jim Thompson wrote:


Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?

...Jim Thompson


I just measured the only piezo disk I have, a .75 inch one. It measures
20 nF.

Cheers,
John

I would be willing to bet if you were to use several different model
instruments to measure that, you won't get inconsistent readings.. I
would think the applied energy from the instrument would cause a
piezoelectric (mechanical change) effect there by giving you different
readings from one to another..


---
Then you _would_ get inconsistent readings.

---
JF
That was an error in my statement, I meant to say "You
would get inconsistent readings" Even if all units were
calibrated with one source, not the piezo as the calibration
source, of course.

Thanks for noticing.


Jamie

"Jamie" t wrote in message
news
John Fields wrote:

On Sun, 20 Feb 2011 10:00:12 -0500, Jamie
t wrote:


John - KD5YI wrote:

On 2/19/2011 6:33 PM, Jim Thompson wrote:


Anyone have good guess for the capacitance of a 1" diameter piezo
disk?

Likewise, how much capacitance in around 100' of typical telephone
twisted pair?
...Jim Thompson


I just measured the only piezo disk I have, a .75 inch one. It measures
20 nF.

Cheers,
John

I would be willing to bet if you were to use several different model
instruments to measure that, you won't get inconsistent readings.. I
would think the applied energy from the instrument would cause a
piezoelectric (mechanical change) effect there by giving you different
readings from one to another..


---
Then you _would_ get inconsistent readings.

---
JF
That was an error in my statement, I meant to say "You
would get inconsistent readings" Even if all units were
calibrated with one source, not the piezo as the calibration
source, of course.

Thanks for noticing.


Jamie

Interesting thought, not sure how inconsistent that number would be
though.
I worked for an Ultrasonics manufacturer building transducers and
amplifiers.
After a transducer (PZT8 bonded to aluminum) was complete, I measured the R
and C
at antiresonance with just a few volts. The tuning components were
calculated with the
R and C and then the amp drove the assembly at hundreds of volts.
I sure hope we didn't mistune because of our low power measurement.
That brings up one of my pet quibbles, Ferrites and A sub L. Always
specified
at one number with no power level attached. Then they are used at several
hundred watts,
and they are at the input to a radio used a few microwatts. I have never
seen a derating
of A sub L dependent on power level.
Mikek