Op amps problem Gain Calculation

[Spehro Pefhany]

On Sat, 05 Feb 2005 07:20:18 -0500, the renowned Boris Mohar
<borism_-void-_@sympatico.ca> wrote:

On Sat, 05 Feb 2005 11:03:00 GMT, "gmv" <noemail@please.123> wrote:

motor caps are too high power for my needs
I am just using small signal here.
NP caps are what i need.
I think the ceramic ones would be perfect.
I just want ones that will read consistant with my C meter.

At these values ceramic caps have very unstable dielectric. Your filter
will be all over the place with respect to temperature. The voltage
coefficient does not look good either.
Try here:
http://www.electronicstalk.com/news/eas/eas123.html.

Electrolytics are actually pretty stable wrt temperature, time and
applied voltage- unlike those pesky hi-K ceramics. Less microphonics,
too. If your meter doesn't read them consistently, maybe it's time to
invest $50 or $60 in a new meter?



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

 

[R.Lewis]

"gmv" <noemail@please.123> wrote in message
news:Y3RMd.19306$C24.13288@attbi_s52...

"R.Lewis" <h.lewis@connect-2.co.uk> wrote in message
news:36htfrF5289nrU1@individual.net...

"gmv" <noemail@please.123> wrote in message
news:HgIMd.47990$EG1.27201@attbi_s53...

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote in message news:1106d0pdpsb0i35@corp.supernews.com...

"gmv" <noemail@please.123> wrote in message
newsczMd.46765$IV5.32350@attbi_s54...

snip

Run it through an A/D to get it into the digital domain where you can
handle
it sensibly without having to consider what temperature, sonics, etc
will
otherwise do to your filters if you need that sort of accuracy.




I must filter out the high stuff first because my sample rate
is only 65539.3 samples per hour and my dynamic range is only
8 bits. Like I told someone else my sensor has a non-linear
response in the frequency range of interest.
2Hz to 1/20 Hz.
It would be so wonderful to have a dead end at 2HZ kind
of filter then most of my troubles would evaporate.

In which case why not, as I said before, run it through an AtoD etc etc. and
do a proper job on it.
Simple enough to tailor exactly to your needs.

 

[Watson A.Name - \"Watt Su]

"gmv" <noemail@please.123> wrote in message
news:EJ1Nd.51210$eT5.4698@attbi_s51...

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote in message news:11097hnlc4n3q25@corp.supernews.com...

"gmv" <noemail@please.123> wrote in message
news:f_QMd.49525$eT5.27123@attbi_s51...
Sorry, Do not know what a DSP/FIR is.
I am using only 8 bit data.
Surprising enough the filters work quite well
between 1Hz and DC just like they do between
1Hz and infinity. The only problem I have is
getting those capacitors in a non-electrolytic form.
I have found I can get pretty good matches in frequency
simply if I can know the true value of the capacitors.
The design matches the theory if only I can
match the capacitors.
I used to laugh at precision and accuracy but
I have found that is the only way to go when
dealing with filter circuits and possibly
oscillator circuits too.
The only way I will play with things like FIR or
DSP is if it will handle data from a non-linearI still think
kind of sensor that tends to overdrive the
preamp at high freqs making it impossible to
look at the low freqs also it got to be cheap.
I need to filter out
the upper freqs right off the bat or it is
impossible to get enough gain to look at the low.

I still think you need to raise the impedance of the circuits
up high enough so that the capacitors are much smaller.

That increases the noise.


Using FET input opamps and megohm resistors, you should be able
to get down to very low freqs with caps of a microfarad.

I think I need BJT types if I remember right
they are lower in noise. I have found chopper
amps to be out of the question.


I offered that Action Electronics web page with the motor
capacitors,
but I don't know if they are electrolytic or not. Maybe someone
could help. They also have tantalom caps, which are more stable
than 'lytics. http://www.action-electronics.com/capacitr.htm

motor caps are too high power for my needs
I am just using small signal here.
NP caps are what i need.

Well, the motor caps are non-polarized. That's what you want.
And they are not electrolytic, I believe, but I'm not certain.
And the power doesn't make any diff, but they are large, and
that might be a problem. As I already mentioned, there are
ceiling fan capacitors at the local hardware store that are
about 10 uF, and are not very large. ANd reasonably priced IIRC.

About noise, you decrease noise by reducing the bandwidth. You
reduce the bandwidth by reducing the load on the tuned circuit.
You do this by increasing the impedance of the load on the tuned
circuit, IOW use a higher resistance, and that means FETs or
other very high impedance amps.

I think you are getting more noise because you are decreasing
the bandwidth by keeping the load the same impedance, but
increasing the tuned circuit impedance. That's backwards
from what you should be doing.

I think the ceramic ones would be perfect.
I just want ones that will read consistant with my C meter.


Thanks to everyone for your answers
but like always I must seek a solution myself
because it is so rare I really find any answers
on these newsgroups.
It is as if the Engineers and Scientists
avoid this internet stuff like it is the plague.
I just tried building my own cap and a monster
size it was and only 3.3nf...they must be very
hard to make at 10uf or higher and be small.
You need to use the same technology that makes
ICs. Thin layer of metal, thin layer of insulator,
do this repeatedly until you get the right value.
Surely there must be a breakthrough in technology
to make decent high value caps.
Sort of like the movie THIS ISLAND EARTH
I need to find that engineers supplier of
interocitor parts.






Yes, a log amp is a possibility, I have already
considered that. But the signals I now receive
are good enough for myself and all I wish to do
is to bring closure to my circuit be acquiring what
I consider to be decent capacitors. These electrolytics
are seemingly only for one frequency because
funny things start happening if you read the
capacitance with different frequencies.
Like I get a lower capacitance at a higher frequency.
I have found no such problems with regular
caps that do not use an electrolytic form.
Your solution would be possible if I had a sensor
resonant at 20 seconds but the Geophone I am using
is resonant at something over 1 Hz.
Geospace has just the device I would like to have
they have a .5 Hz Geophone but they want about
$3000 for one and that is way too high for someone
living on Social Security.


"Rob Gaddi" <rgaddi@bcm.YUMMYSPAMtmc.edu> wrote in message
news:cu0elc$t4c@gazette.corp.bcm.tmc.edu...
While I hate to give my usual answer, have you considered just
digitizing the data and running it through a DSP? You're talking
about some massively slow filters to be trying to make with any
reliable tolerance in analog, and with component values that large
it's not going to be cheap. Plus you can use a linear FIR filter
and not have to worry about the phase distortion you were
mentioning.

If your noise is really swamping the signal, and dynamic range is
a
concern, at the low speeds you're talking about you could run
the signal through a log amp before you A/D it.


Lucky for me different phases of Earthquakes
seem to prefer different frequencies.
But my picture will never be as good as the
big boys.
Just too darn noisy at this location.
I get a terrible noise at maybe 15 Hz or so.
Need to filter like crazy to get rid of it.
It drowns out just about everything i try to do.
I suspect but can not prove that my geophone
is out of spec and not working at the 1Hz
it is supposed to.
The only adjustment I can make is to center the
mass in the housing. If there is a way to lower the
resonant freq I would sure like to know.
I am thinking of finding some weights to put on
the adjustment screw as much weight as can still be
centered.
But it is my experience that for a spring to
lower its frequency it needs to extend or compress
farther in distance. similar to a pendulums length.
T=2PiSqRt(length/gravity)

 

[Charlie+]

On Thu, 03 Feb 2005 21:37:45 GMT, "gmv" <noemail@please.123> wrote as
underneath my scribble :

Just a thaught on your original question if you are still going there!
- Have you thought of a Peak Atlas LCR Analyser? It uses DC transient
analysis to measure in the range 1uF upwards (10,000uF) at about 1V.
accuracy approaches what you want absolute. See www.peakelec.co.uk
but you can get pretty good repeatability which might be the key
I can take 10 readings off the same 100uF electrolytic and let you
know the variation if it wd help.? what voltage rating?
Charlie+.

Is there anyway to accurately measure the
capacitance of an electrolytic capacitor
in the range of 10uf to 100uf.

I am trying to get a reading
within 1% of reality.

Help here is appreciated.

 

[Watson A.Name - \"Watt Su]

"gmv" <noemail@please.123> wrote in message
news:0F3Nd.50241$EG1.24027@attbi_s53...

Yes, that is the kind of thing I am looking for.
In case you are wondering the thing I want to
use them in is here:

[img:ae8273816a]http://files.photojerk.com/gmvoeth/circuita.JPG[/img:ae8273816a]

As you can tell I am no expert but i can tell you
this will show Earthquakes in a relatively noisy area.
Just got a big one from the Philippines I think.
The big capacitors on the front end are just to
simulate the mass/housing relationship in the
geophone. They are not a reality as far as
capacitors go.

The last three filters are simple 6dB per octave rolloff filters, and
they claim to be different freqs, but their parts values are identical,
so something is wrong there. But they are preceded by three bandpass
filters in parallel, so there are some incongruities in thie circuit.
And there seems to be a lot of room for improvement.

"Boris Mohar" <borism_-void-_@sympatico.ca> wrote in message
news:75e9011tvdtt0kmg1202q713e35udgg5rh@4ax.com...
On Sat, 05 Feb 2005 11:03:00 GMT, "gmv" <noemail@please.123> wrote:

motor caps are too high power for my needs
I am just using small signal here.
NP caps are what i need.
I think the ceramic ones would be perfect.
I just want ones that will read consistant with my C meter.

At these values ceramic caps have very unstable dielectric. Your
filter
will be all over the place with respect to temperature. The voltage
coefficient does not look good either.
Try here:
http://www.electronicstalk.com/news/eas/eas123.html.



Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things)
http://www.viatrack.ca

 

[Watson A.Name - \"Watt Su]

"Charlie+" <charlie@xxx.net> wrote in message
news:395a01p8rbd7j5loadqvdqrjm8irpe4ojp@4ax.com...

On Thu, 03 Feb 2005 21:37:45 GMT, "gmv" <noemail@please.123> wrote as
underneath my scribble :

Just a thaught on your original question if you are still going there!
- Have you thought of a Peak Atlas LCR Analyser? It uses DC transient
analysis to measure in the range 1uF upwards (10,000uF) at about 1V.
accuracy approaches what you want absolute. See www.peakelec.co.uk

Probably pretty hard to get one in the U.S. But he could plug the cap
into a standard astable circuit using a 555, and if the values of the
resistors are accurate, he could get a fairly close value for the
capacitance.

but you can get pretty good repeatability which might be the key
I can take 10 readings off the same 100uF electrolytic and let you
know the variation if it wd help.? what voltage rating?
Charlie+.

Is there anyway to accurately measure the
capacitance of an electrolytic capacitor
in the range of 10uf to 100uf.

I am trying to get a reading
within 1% of reality.

Help here is appreciated.

 

[gmv]

Look more closely and tell me what can be done
because I am at at a dead end.
The noise is horrible above 2Hz I really
need a filter that has a precipitous
dropoff between 2 and 3 Hz in order get the
gain to see anything worth watching.
The phase distortions are terrible too
but if I want to see a meaningful picture i have
no other choices I know of. I have tried just about
everything under the sun and these BP filters seem
the very best for me and my location.

The last three filters simply help to steepen
the high rolloff so i can get more gain at
the lower without being swamped by noise.

The Earthquake people want me to look at
..5 to 2Hz but that just is not possible for me
unless I can roll 3 Hzand above -24db from what i get at 2Hz.
I need a miracle filter that does not exist.




"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote in message news:110a7kmdfs6d633@corp.supernews.com...

"gmv" <noemail@please.123> wrote in message
news:0F3Nd.50241$EG1.24027@attbi_s53...
Yes, that is the kind of thing I am looking for.
In case you are wondering the thing I want to
use them in is here:

[img:753bfd2fe1]http://files.photojerk.com/gmvoeth/circuita.JPG[/img:753bfd2fe1]

As you can tell I am no expert but i can tell you
this will show Earthquakes in a relatively noisy area.
Just got a big one from the Philippines I think.
The big capacitors on the front end are just to
simulate the mass/housing relationship in the
geophone. They are not a reality as far as
capacitors go.

The last three filters are simple 6dB per octave rolloff filters, and
they claim to be different freqs, but their parts values are identical,
so something is wrong there. But they are preceded by three bandpass
filters in parallel, so there are some incongruities in thie circuit.
And there seems to be a lot of room for improvement.


"Boris Mohar" <borism_-void-_@sympatico.ca> wrote in message
news:75e9011tvdtt0kmg1202q713e35udgg5rh@4ax.com...
On Sat, 05 Feb 2005 11:03:00 GMT, "gmv" <noemail@please.123> wrote:

motor caps are too high power for my needs
I am just using small signal here.
NP caps are what i need.
I think the ceramic ones would be perfect.
I just want ones that will read consistant with my C meter.

At these values ceramic caps have very unstable dielectric. Your
filter
will be all over the place with respect to temperature. The voltage
coefficient does not look good either.
Try here:
http://www.electronicstalk.com/news/eas/eas123.html.



Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things)
http://www.viatrack.ca

 

[gmv]

My meter says the reading will
change if the leakage resistance is low
and that seems to be true for just about
most Electrolytics i test.
Maybe what i need is a high quality Electrolytic
with fantastic high leakage resistance.

"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> wrote in message news:5jh901tjbopm0mh3pvf6hr381mdvvddpqs@4ax.com...

On Sat, 05 Feb 2005 07:20:18 -0500, the renowned Boris Mohar
borism_-void-_@sympatico.ca> wrote:

On Sat, 05 Feb 2005 11:03:00 GMT, "gmv" <noemail@please.123> wrote:

motor caps are too high power for my needs
I am just using small signal here.
NP caps are what i need.
I think the ceramic ones would be perfect.
I just want ones that will read consistant with my C meter.

At these values ceramic caps have very unstable dielectric. Your filter
will be all over the place with respect to temperature. The voltage
coefficient does not look good either.
Try here:
http://www.electronicstalk.com/news/eas/eas123.html.

Electrolytics are actually pretty stable wrt temperature, time and
applied voltage- unlike those pesky hi-K ceramics. Less microphonics,
too. If your meter doesn't read them consistently, maybe it's time to
invest $50 or $60 in a new meter?



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

 

[gmv]

Interesting,
I always thought the opamp buffered the output
so you could hook it to anything between 2K
and infinity.
I will keep in mind what you have said.
I have noticed a terrible ringing effect at Q
5 and above.
Maybe that is what you are talking about.
In any case I really need to see things between .5Hz
and 2Hz. It is only the noise in my local area that
keeps me from doing this as far as I can tell.

http://home.mchsi.com/~gmvoeth/index.html

will show a bit more of what I am doing.


"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote in message news:1109v26sjt1i70c@corp.supernews.com...

"gmv" <noemail@please.123> wrote in message
news:EJ1Nd.51210$eT5.4698@attbi_s51...

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote in message news:11097hnlc4n3q25@corp.supernews.com...

"gmv" <noemail@please.123> wrote in message
news:f_QMd.49525$eT5.27123@attbi_s51...
Sorry, Do not know what a DSP/FIR is.
I am using only 8 bit data.
Surprising enough the filters work quite well
between 1Hz and DC just like they do between
1Hz and infinity. The only problem I have is
getting those capacitors in a non-electrolytic form.
I have found I can get pretty good matches in frequency
simply if I can know the true value of the capacitors.
The design matches the theory if only I can
match the capacitors.
I used to laugh at precision and accuracy but
I have found that is the only way to go when
dealing with filter circuits and possibly
oscillator circuits too.
The only way I will play with things like FIR or
DSP is if it will handle data from a non-linearI still think
kind of sensor that tends to overdrive the
preamp at high freqs making it impossible to
look at the low freqs also it got to be cheap.
I need to filter out
the upper freqs right off the bat or it is
impossible to get enough gain to look at the low.

I still think you need to raise the impedance of the circuits
up high enough so that the capacitors are much smaller.

That increases the noise.


Using FET input opamps and megohm resistors, you should be able
to get down to very low freqs with caps of a microfarad.

I think I need BJT types if I remember right
they are lower in noise. I have found chopper
amps to be out of the question.


I offered that Action Electronics web page with the motor
capacitors,
but I don't know if they are electrolytic or not. Maybe someone
could help. They also have tantalom caps, which are more stable
than 'lytics. http://www.action-electronics.com/capacitr.htm

motor caps are too high power for my needs
I am just using small signal here.
NP caps are what i need.

Well, the motor caps are non-polarized. That's what you want.
And they are not electrolytic, I believe, but I'm not certain.
And the power doesn't make any diff, but they are large, and
that might be a problem. As I already mentioned, there are
ceiling fan capacitors at the local hardware store that are
about 10 uF, and are not very large. ANd reasonably priced IIRC.

About noise, you decrease noise by reducing the bandwidth. You
reduce the bandwidth by reducing the load on the tuned circuit.
You do this by increasing the impedance of the load on the tuned
circuit, IOW use a higher resistance, and that means FETs or
other very high impedance amps.

I think you are getting more noise because you are decreasing
the bandwidth by keeping the load the same impedance, but
increasing the tuned circuit impedance. That's backwards
from what you should be doing.

I think the ceramic ones would be perfect.
I just want ones that will read consistant with my C meter.


Thanks to everyone for your answers
but like always I must seek a solution myself
because it is so rare I really find any answers
on these newsgroups.
It is as if the Engineers and Scientists
avoid this internet stuff like it is the plague.
I just tried building my own cap and a monster
size it was and only 3.3nf...they must be very
hard to make at 10uf or higher and be small.
You need to use the same technology that makes
ICs. Thin layer of metal, thin layer of insulator,
do this repeatedly until you get the right value.
Surely there must be a breakthrough in technology
to make decent high value caps.
Sort of like the movie THIS ISLAND EARTH
I need to find that engineers supplier of
interocitor parts.






Yes, a log amp is a possibility, I have already
considered that. But the signals I now receive
are good enough for myself and all I wish to do
is to bring closure to my circuit be acquiring what
I consider to be decent capacitors. These electrolytics
are seemingly only for one frequency because
funny things start happening if you read the
capacitance with different frequencies.
Like I get a lower capacitance at a higher frequency.
I have found no such problems with regular
caps that do not use an electrolytic form.
Your solution would be possible if I had a sensor
resonant at 20 seconds but the Geophone I am using
is resonant at something over 1 Hz.
Geospace has just the device I would like to have
they have a .5 Hz Geophone but they want about
$3000 for one and that is way too high for someone
living on Social Security.


"Rob Gaddi" <rgaddi@bcm.YUMMYSPAMtmc.edu> wrote in message
news:cu0elc$t4c@gazette.corp.bcm.tmc.edu...
While I hate to give my usual answer, have you considered just
digitizing the data and running it through a DSP? You're talking
about some massively slow filters to be trying to make with any
reliable tolerance in analog, and with component values that large
it's not going to be cheap. Plus you can use a linear FIR filter
and not have to worry about the phase distortion you were
mentioning.

If your noise is really swamping the signal, and dynamic range is
a
concern, at the low speeds you're talking about you could run
the signal through a log amp before you A/D it.


Lucky for me different phases of Earthquakes
seem to prefer different frequencies.
But my picture will never be as good as the
big boys.
Just too darn noisy at this location.
I get a terrible noise at maybe 15 Hz or so.
Need to filter like crazy to get rid of it.
It drowns out just about everything i try to do.
I suspect but can not prove that my geophone
is out of spec and not working at the 1Hz
it is supposed to.
The only adjustment I can make is to center the
mass in the housing. If there is a way to lower the
resonant freq I would sure like to know.
I am thinking of finding some weights to put on
the adjustment screw as much weight as can still be
centered.
But it is my experience that for a spring to
lower its frequency it needs to extend or compress
farther in distance. similar to a pendulums length.
T=2PiSqRt(length/gravity)

 

[gmv]

The noise above 2Hz is so great it will clip before I can look at
my area of interest.


"R.Lewis" <h.lewis@connect-2.co.uk> wrote in message news:36kbo6F52lcvnU1@individual.net...

"gmv" <noemail@please.123> wrote in message
news:Y3RMd.19306$C24.13288@attbi_s52...

"R.Lewis" <h.lewis@connect-2.co.uk> wrote in message
news:36htfrF5289nrU1@individual.net...

"gmv" <noemail@please.123> wrote in message
news:HgIMd.47990$EG1.27201@attbi_s53...

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote in message news:1106d0pdpsb0i35@corp.supernews.com...

"gmv" <noemail@please.123> wrote in message
newsczMd.46765$IV5.32350@attbi_s54...

snip

Run it through an A/D to get it into the digital domain where you can
handle
it sensibly without having to consider what temperature, sonics, etc
will
otherwise do to your filters if you need that sort of accuracy.




I must filter out the high stuff first because my sample rate
is only 65539.3 samples per hour and my dynamic range is only
8 bits. Like I told someone else my sensor has a non-linear
response in the frequency range of interest.
2Hz to 1/20 Hz.
It would be so wonderful to have a dead end at 2HZ kind
of filter then most of my troubles would evaporate.


In which case why not, as I said before, run it through an AtoD etc etc. and
do a proper job on it.
Simple enough to tailor exactly to your needs.

 

[gmv]

Exactly what I was considering.
Possibly a simple RC inverter oscillator.


"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote in message news:110a7te1fihrmd9@corp.supernews.com...

"Charlie+" <charlie@xxx.net> wrote in message
news:395a01p8rbd7j5loadqvdqrjm8irpe4ojp@4ax.com...
On Thu, 03 Feb 2005 21:37:45 GMT, "gmv" <noemail@please.123> wrote as
underneath my scribble :

Just a thaught on your original question if you are still going there!
- Have you thought of a Peak Atlas LCR Analyser? It uses DC transient
analysis to measure in the range 1uF upwards (10,000uF) at about 1V.
accuracy approaches what you want absolute. See www.peakelec.co.uk

Probably pretty hard to get one in the U.S. But he could plug the cap
into a standard astable circuit using a 555, and if the values of the
resistors are accurate, he could get a fairly close value for the
capacitance.

but you can get pretty good repeatability which might be the key
I can take 10 readings off the same 100uF electrolytic and let you
know the variation if it wd help.? what voltage rating?
Charlie+.

Is there anyway to accurately measure the
capacitance of an electrolytic capacitor
in the range of 10uf to 100uf.

I am trying to get a reading
within 1% of reality.

Help here is appreciated.

 

[gmv]

I built a high Q filter circuit and could
get it to ring and when it did it rang
at the correct frequency so I guess my
meter is telling me the truth.

"Charlie+" <charlie@xxx.net> wrote in message news:7jpb01dj59j1lj61np1tjeq5454cqhcnks@4ax.com...

On Sun, 06 Feb 2005 00:59:10 GMT, "gmv" <noemail@please.123> wrote as
underneath my scribble :

Problem is getting your absolute value with a homemade solution unless
you have a calibrated standard to go from/compare with especially with
large caps as there are residual voltage issues.
I have an old homemade oscillator based L/C bridge measurer which has
very good repeatability and accuracy with small values but relies on
comparison in any range with calibrated standards - it is rough at
anything over 1 uF as far as repeatability goes especially with
electrolytics, over 5uF forget it! ; and this unit was not
particularly cheap or simple to make at the time!
Charlie+

Exactly what I was considering.
Possibly a simple RC inverter oscillator.

 

[Watson A.Name - \"Watt Su]

"gmv" <noemail@please.123> wrote in message
news:jJdNd.21541$C24.9629@attbi_s52...

Interesting,
I always thought the opamp buffered the output
so you could hook it to anything between 2K
and infinity.
I will keep in mind what you have said.
I have noticed a terrible ringing effect at Q
5 and above.
Maybe that is what you are talking about.
In any case I really need to see things between .5Hz
and 2Hz. It is only the noise in my local area that
keeps me from doing this as far as I can tell.

http://home.mchsi.com/~gmvoeth/index.html

will show a bit more of what I am doing.

Buy the RS printed circuit board that has the same layout as the
breadoard. Build the circuit on that board, and put it inside of a
metal enclosure, so that most of the noise is kept out of the circuit.

All preamplification should be done as close as possible to the
geophone, to get the signal well above the noise _before_ it goes any
distance.

Filtering should be done at the other end, to get rid of noise in the
long transmission line between the sensor and the PC.

One other important point. The outside can of the electrolytic is at
signal level, and is a large capacitance to the outside world. Just
shielding these from outside noise should help. You might consider
putting some aluminum foil over the ones at the input, and grounding the
foil to common. Just to see how much it will help to put the whole
thing in an enclosure.

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote in message news:1109v26sjt1i70c@corp.supernews.com...

"gmv" <noemail@please.123> wrote in message
news:EJ1Nd.51210$eT5.4698@attbi_s51...

"Watson A.Name - "Watt Sun, the Dark Remover""
NOSPAM@dslextreme.com
wrote in message news:11097hnlc4n3q25@corp.supernews.com...

"gmv" <noemail@please.123> wrote in message
news:f_QMd.49525$eT5.27123@attbi_s51...
Sorry, Do not know what a DSP/FIR is.
I am using only 8 bit data.
Surprising enough the filters work quite well
between 1Hz and DC just like they do between
1Hz and infinity. The only problem I have is
getting those capacitors in a non-electrolytic form.
I have found I can get pretty good matches in frequency
simply if I can know the true value of the capacitors.
The design matches the theory if only I can
match the capacitors.
I used to laugh at precision and accuracy but
I have found that is the only way to go when
dealing with filter circuits and possibly
oscillator circuits too.
The only way I will play with things like FIR or
DSP is if it will handle data from a non-linearI still think
kind of sensor that tends to overdrive the
preamp at high freqs making it impossible to
look at the low freqs also it got to be cheap.
I need to filter out
the upper freqs right off the bat or it is
impossible to get enough gain to look at the low.

I still think you need to raise the impedance of the circuits
up high enough so that the capacitors are much smaller.

That increases the noise.


Using FET input opamps and megohm resistors, you should be able
to get down to very low freqs with caps of a microfarad.

I think I need BJT types if I remember right
they are lower in noise. I have found chopper
amps to be out of the question.


I offered that Action Electronics web page with the motor
capacitors,
but I don't know if they are electrolytic or not. Maybe someone
could help. They also have tantalom caps, which are more stable
than 'lytics. http://www.action-electronics.com/capacitr.htm

motor caps are too high power for my needs
I am just using small signal here.
NP caps are what i need.

Well, the motor caps are non-polarized. That's what you want.
And they are not electrolytic, I believe, but I'm not certain.
And the power doesn't make any diff, but they are large, and
that might be a problem. As I already mentioned, there are
ceiling fan capacitors at the local hardware store that are
about 10 uF, and are not very large. ANd reasonably priced IIRC.

About noise, you decrease noise by reducing the bandwidth. You
reduce the bandwidth by reducing the load on the tuned circuit.
You do this by increasing the impedance of the load on the tuned
circuit, IOW use a higher resistance, and that means FETs or
other very high impedance amps.

I think you are getting more noise because you are decreasing
the bandwidth by keeping the load the same impedance, but
increasing the tuned circuit impedance. That's backwards
from what you should be doing.

I think the ceramic ones would be perfect.
I just want ones that will read consistant with my C meter.


Thanks to everyone for your answers
but like always I must seek a solution myself
because it is so rare I really find any answers
on these newsgroups.
It is as if the Engineers and Scientists
avoid this internet stuff like it is the plague.
I just tried building my own cap and a monster
size it was and only 3.3nf...they must be very
hard to make at 10uf or higher and be small.
You need to use the same technology that makes
ICs. Thin layer of metal, thin layer of insulator,
do this repeatedly until you get the right value.
Surely there must be a breakthrough in technology
to make decent high value caps.
Sort of like the movie THIS ISLAND EARTH
I need to find that engineers supplier of
interocitor parts.






Yes, a log amp is a possibility, I have already
considered that. But the signals I now receive
are good enough for myself and all I wish to do
is to bring closure to my circuit be acquiring what
I consider to be decent capacitors. These electrolytics
are seemingly only for one frequency because
funny things start happening if you read the
capacitance with different frequencies.
Like I get a lower capacitance at a higher frequency.
I have found no such problems with regular
caps that do not use an electrolytic form.
Your solution would be possible if I had a sensor
resonant at 20 seconds but the Geophone I am using
is resonant at something over 1 Hz.
Geospace has just the device I would like to have
they have a .5 Hz Geophone but they want about
$3000 for one and that is way too high for someone
living on Social Security.


"Rob Gaddi" <rgaddi@bcm.YUMMYSPAMtmc.edu> wrote in message
news:cu0elc$t4c@gazette.corp.bcm.tmc.edu...
While I hate to give my usual answer, have you considered just
digitizing the data and running it through a DSP? You're talking
about some massively slow filters to be trying to make with
any
reliable tolerance in analog, and with component values that
large
it's not going to be cheap. Plus you can use a linear FIR
filter
and not have to worry about the phase distortion you were
mentioning.

If your noise is really swamping the signal, and dynamic range
is
a
concern, at the low speeds you're talking about you could run
the signal through a log amp before you A/D it.


Lucky for me different phases of Earthquakes
seem to prefer different frequencies.
But my picture will never be as good as the
big boys.
Just too darn noisy at this location.
I get a terrible noise at maybe 15 Hz or so.
Need to filter like crazy to get rid of it.
It drowns out just about everything i try to do.
I suspect but can not prove that my geophone
is out of spec and not working at the 1Hz
it is supposed to.
The only adjustment I can make is to center the
mass in the housing. If there is a way to lower the
resonant freq I would sure like to know.
I am thinking of finding some weights to put on
the adjustment screw as much weight as can still be
centered.
But it is my experience that for a spring to
lower its frequency it needs to extend or compress
farther in distance. similar to a pendulums length.
T=2PiSqRt(length/gravity)

 

[gmv]

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote in message news:110cnbn267cd7fe@corp.supernews.com...

"gmv" <noemail@please.123> wrote in message
news:jJdNd.21541$C24.9629@attbi_s52...
Interesting,
I always thought the opamp buffered the output
so you could hook it to anything between 2K
and infinity.
I will keep in mind what you have said.
I have noticed a terrible ringing effect at Q
5 and above.
Maybe that is what you are talking about.
In any case I really need to see things between .5Hz
and 2Hz. It is only the noise in my local area that
keeps me from doing this as far as I can tell.

http://home.mchsi.com/~gmvoeth/index.html

will show a bit more of what I am doing.

Buy the RS printed circuit board that has the same layout as the
breadoard. Build the circuit on that board, and put it inside of a
metal enclosure, so that most of the noise is kept out of the circuit.

What is "RS printed circuit board " ?

I have settled on using only a single filter
as is now posted to my web site. This will
limit one to only seeing P waves but in
this noisy environment it is the best I can do.
I agree with everything you say except I can not
put a preamp outside with the Geophone.
There is a circuit I have included not on the
schematic and it is a 567 tone decoder on the back
end to decode WWV calibration marks.

Thanks for your advice, I can see a lot of
common sense to it. But I still do not
know how to buy a circuit board that already
has my layout on it. I figure I will have
to do the layout and etching etc... myself.

All preamplification should be done as close as possible to the
geophone, to get the signal well above the noise _before_ it goes any
distance.

Filtering should be done at the other end, to get rid of noise in the
long transmission line between the sensor and the PC.

One other important point. The outside can of the electrolytic is at
signal level, and is a large capacitance to the outside world. Just
shielding these from outside noise should help. You might consider
putting some aluminum foil over the ones at the input, and grounding the
foil to common. Just to see how much it will help to put the whole
thing in an enclosure.

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote in message news:1109v26sjt1i70c@corp.supernews.com...

"gmv" <noemail@please.123> wrote in message
news:EJ1Nd.51210$eT5.4698@attbi_s51...

"Watson A.Name - "Watt Sun, the Dark Remover""
NOSPAM@dslextreme.com
wrote in message news:11097hnlc4n3q25@corp.supernews.com...

"gmv" <noemail@please.123> wrote in message
news:f_QMd.49525$eT5.27123@attbi_s51...
Sorry, Do not know what a DSP/FIR is.
I am using only 8 bit data.
Surprising enough the filters work quite well
between 1Hz and DC just like they do between
1Hz and infinity. The only problem I have is
getting those capacitors in a non-electrolytic form.
I have found I can get pretty good matches in frequency
simply if I can know the true value of the capacitors.
The design matches the theory if only I can
match the capacitors.
I used to laugh at precision and accuracy but
I have found that is the only way to go when
dealing with filter circuits and possibly
oscillator circuits too.
The only way I will play with things like FIR or
DSP is if it will handle data from a non-linearI still think
kind of sensor that tends to overdrive the
preamp at high freqs making it impossible to
look at the low freqs also it got to be cheap.
I need to filter out
the upper freqs right off the bat or it is
impossible to get enough gain to look at the low.

I still think you need to raise the impedance of the circuits
up high enough so that the capacitors are much smaller.

That increases the noise.


Using FET input opamps and megohm resistors, you should be able
to get down to very low freqs with caps of a microfarad.

I think I need BJT types if I remember right
they are lower in noise. I have found chopper
amps to be out of the question.


I offered that Action Electronics web page with the motor
capacitors,
but I don't know if they are electrolytic or not. Maybe someone
could help. They also have tantalom caps, which are more stable
than 'lytics. http://www.action-electronics.com/capacitr.htm

motor caps are too high power for my needs
I am just using small signal here.
NP caps are what i need.

Well, the motor caps are non-polarized. That's what you want.
And they are not electrolytic, I believe, but I'm not certain.
And the power doesn't make any diff, but they are large, and
that might be a problem. As I already mentioned, there are
ceiling fan capacitors at the local hardware store that are
about 10 uF, and are not very large. ANd reasonably priced IIRC.

About noise, you decrease noise by reducing the bandwidth. You
reduce the bandwidth by reducing the load on the tuned circuit.
You do this by increasing the impedance of the load on the tuned
circuit, IOW use a higher resistance, and that means FETs or
other very high impedance amps.

I think you are getting more noise because you are decreasing
the bandwidth by keeping the load the same impedance, but
increasing the tuned circuit impedance. That's backwards
from what you should be doing.

I think the ceramic ones would be perfect.
I just want ones that will read consistant with my C meter.


Thanks to everyone for your answers
but like always I must seek a solution myself
because it is so rare I really find any answers
on these newsgroups.
It is as if the Engineers and Scientists
avoid this internet stuff like it is the plague.
I just tried building my own cap and a monster
size it was and only 3.3nf...they must be very
hard to make at 10uf or higher and be small.
You need to use the same technology that makes
ICs. Thin layer of metal, thin layer of insulator,
do this repeatedly until you get the right value.
Surely there must be a breakthrough in technology
to make decent high value caps.
Sort of like the movie THIS ISLAND EARTH
I need to find that engineers supplier of
interocitor parts.






Yes, a log amp is a possibility, I have already
considered that. But the signals I now receive
are good enough for myself and all I wish to do
is to bring closure to my circuit be acquiring what
I consider to be decent capacitors. These electrolytics
are seemingly only for one frequency because
funny things start happening if you read the
capacitance with different frequencies.
Like I get a lower capacitance at a higher frequency.
I have found no such problems with regular
caps that do not use an electrolytic form.
Your solution would be possible if I had a sensor
resonant at 20 seconds but the Geophone I am using
is resonant at something over 1 Hz.
Geospace has just the device I would like to have
they have a .5 Hz Geophone but they want about
$3000 for one and that is way too high for someone
living on Social Security.


"Rob Gaddi" <rgaddi@bcm.YUMMYSPAMtmc.edu> wrote in message
news:cu0elc$t4c@gazette.corp.bcm.tmc.edu...
While I hate to give my usual answer, have you considered just
digitizing the data and running it through a DSP? You're talking
about some massively slow filters to be trying to make with
any
reliable tolerance in analog, and with component values that
large
it's not going to be cheap. Plus you can use a linear FIR
filter
and not have to worry about the phase distortion you were
mentioning.

If your noise is really swamping the signal, and dynamic range
is
a
concern, at the low speeds you're talking about you could run
the signal through a log amp before you A/D it.


Lucky for me different phases of Earthquakes
seem to prefer different frequencies.
But my picture will never be as good as the
big boys.
Just too darn noisy at this location.
I get a terrible noise at maybe 15 Hz or so.
Need to filter like crazy to get rid of it.
It drowns out just about everything i try to do.
I suspect but can not prove that my geophone
is out of spec and not working at the 1Hz
it is supposed to.
The only adjustment I can make is to center the
mass in the housing. If there is a way to lower the
resonant freq I would sure like to know.
I am thinking of finding some weights to put on
the adjustment screw as much weight as can still be
centered.
But it is my experience that for a spring to
lower its frequency it needs to extend or compress
farther in distance. similar to a pendulums length.
T=2PiSqRt(length/gravity)

 

[Jamie]

gmv wrote:

Look more closely and tell me what can be done
because I am at at a dead end.
The noise is horrible above 2Hz I really
need a filter that has a precipitous
dropoff between 2 and 3 Hz in order get the
gain to see anything worth watching.
The phase distortions are terrible too
but if I want to see a meaningful picture i have
no other choices I know of. I have tried just about
everything under the sun and these BP filters seem
the very best for me and my location.

The last three filters simply help to steepen
the high rolloff so i can get more gain at
the lower without being swamped by noise.

The Earthquake people want me to look at
.5 to 2Hz but that just is not possible for me
unless I can roll 3 Hzand above -24db from what i get at 2Hz.
I need a miracle filter that does not exist.




have you thought of looking into doing some FFT (DFT) code?

i don't know exactly what your doing but, its also possible to
to mix your input signal to generate a much higher signal.
something like the use of a LM1496 comes to mind.

 

[gmv]

Yes I think I understand what you mean
but i want to remain baseband at the moment.
The FFT will do no good for my purposes
except to identify the noise I am
fighting. I already know the noise is betweeen
2.5 Hz and 15 Hz that is causing my troubles.
But you got to realize a geophone is
most sensitive above its resonant freq
and that is the whole root of my troubles.
What Im trying to do is make a circuit that will
squish the noise down from the sensor so i can boost
those freqs I really want to see.
This noise is overwhelming it will jam all else
I am trying to look at. It is caused by human
activity and short of driving off most the people but me
in this town there is little i can do to stop it.
The high freqs will drive my amplifier into
saturation and cutoff so when that happens
it is no good for seeing anything but the harmonics
of the noise.
This time of year is the worst because all
the tourists are in town and it swells our
population to more than twice its normal size.
I find this problem interesting and have decided
to use a narrow band filter with a Q about 1 and
centered about 1/1.5Hz and at the moment that is
the very best I can do. I have found using more than
one filter in parallel only serves to complicate
the grams I am trying to achieve.

Thanks for your input.




"Jamie" <jamie_5_not_valid_after_5_Please@charter.net> wrote in message news:iJNNd.33372$3m.15296@fe06.lga...

gmv wrote:

Look more closely and tell me what can be done
because I am at at a dead end.
The noise is horrible above 2Hz I really
need a filter that has a precipitous
dropoff between 2 and 3 Hz in order get the
gain to see anything worth watching.
The phase distortions are terrible too
but if I want to see a meaningful picture i have
no other choices I know of. I have tried just about
everything under the sun and these BP filters seem
the very best for me and my location.

The last three filters simply help to steepen
the high rolloff so i can get more gain at
the lower without being swamped by noise.

The Earthquake people want me to look at
.5 to 2Hz but that just is not possible for me
unless I can roll 3 Hzand above -24db from what i get at 2Hz.
I need a miracle filter that does not exist.




have you thought of looking into doing some FFT (DFT) code?

i don't know exactly what your doing but, its also possible to
to mix your input signal to generate a much higher signal.
something like the use of a LM1496 comes to mind.

 

[gmv]

I call that frequency translation but it will not work here
because the problem lies in the sensitivity profile of the sensor
itself.
I need to squish down the normal operating range
of the geophone so I can look at the signals
riding underneath the resonant point.

What I call equalization seems to work which is using
a LPF with a CF under the range you want to view
It serves to push down everything over the rolloff
including the noise you want to squish.
Then the range between the rolloff and resonance becomes
somewhat flat in response.

Thanks for your input.



"loedown" <zero242@internode.on.net> wrote in message news:4207ea40$1@duster.adelaide.on.net...

Hi All,
I know very little about radio and the like, but could some form of superheterodyning be done in this instance, the
idea of AM, or FM to combine the slow signal with much higher frequency?

Paul

 

[Watson A.Name - \"Watt Su]

"gmv" <noemail@please.123> wrote in message
news:J7MNd.24453$C24.9065@attbi_s52...

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote in message news:110cnbn267cd7fe@corp.supernews.com...

"gmv" <noemail@please.123> wrote in message
news:jJdNd.21541$C24.9629@attbi_s52...
Interesting,
I always thought the opamp buffered the output
so you could hook it to anything between 2K
and infinity.
I will keep in mind what you have said.
I have noticed a terrible ringing effect at Q
5 and above.
Maybe that is what you are talking about.
In any case I really need to see things between .5Hz
and 2Hz. It is only the noise in my local area that
keeps me from doing this as far as I can tell.

http://home.mchsi.com/~gmvoeth/index.html

will show a bit more of what I am doing.

Buy the RS printed circuit board that has the same layout as the
breadoard. Build the circuit on that board, and put it inside of a
metal enclosure, so that most of the noise is kept out of the
circuit.

What is "RS printed circuit board " ?

RS = Radio Shack AKA Radio Scrap, etc. They sell a PC board that has
the same layout as the breadboard. Makes it easy to transfer the
circuit to a permanent circuit board.

I have settled on using only a single filter
as is now posted to my web site. This will
limit one to only seeing P waves but in
this noisy environment it is the best I can do.
I agree with everything you say except I can not
put a preamp outside with the Geophone.

Well, that's probably the reason why you are getting so much noise!

There is a circuit I have included not on the
schematic and it is a 567 tone decoder on the back
end to decode WWV calibration marks.

Thanks for your advice, I can see a lot of
common sense to it. But I still do not
know how to buy a circuit board that already
has my layout on it. I figure I will have
to do the layout and etching etc... myself.

I'm not sure you understand. The hole patterns match those on the
breadboard.
Here it is, it's catalog # 276-170 and costs a bit over $3.
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fnam
e=CTLG%5F011%5F002%5F002%5F000&product%5Fid=276%2D170&MSCSProfile=745D84
CBF04D14A48AA6FF9C89D722C0BA68C1B04FE384678A5285FCD6E056B17AF21627FDABE3
16B90B3C038D68EBD6B7F9F3BD1712EAA9951ACB2590A05C6517EFE46941FEFDD1985D4E
FD6321F5E70B4DE9B6C1D45512DCD9FB3DBCACB9479D26760FAF1D7B193B4FEA078B5E09
80BDD61634ABB7D328B012D36915420A2B457BE162481F674B

All preamplification should be done as close as possible to the
geophone, to get the signal well above the noise _before_ it goes
any
distance.

Filtering should be done at the other end, to get rid of noise in
the
long transmission line between the sensor and the PC.

One other important point. The outside can of the electrolytic is
at
signal level, and is a large capacitance to the outside world. Just
shielding these from outside noise should help. You might consider
putting some aluminum foil over the ones at the input, and grounding
the
foil to common. Just to see how much it will help to put the whole
thing in an enclosure.

[snip]

 

[gmv]

I think this is the link you mean:
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F011%5F002%5F002%5F000&product%5Fid=276%2D170

The one you gave me would not function.

Yes, I will eventually do this.
I am still debating whether or not to use
what I call equalization in my circuit.

Thanks for your input.

--
Regards;
gmv


"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote in message news:110h4qnsbpb3rf2@corp.supernews.com...

"gmv" <noemail@please.123> wrote in message
news:J7MNd.24453$C24.9065@attbi_s52...

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote in message news:110cnbn267cd7fe@corp.supernews.com...

"gmv" <noemail@please.123> wrote in message
news:jJdNd.21541$C24.9629@attbi_s52...
Interesting,
I always thought the opamp buffered the output
so you could hook it to anything between 2K
and infinity.
I will keep in mind what you have said.
I have noticed a terrible ringing effect at Q
5 and above.
Maybe that is what you are talking about.
In any case I really need to see things between .5Hz
and 2Hz. It is only the noise in my local area that
keeps me from doing this as far as I can tell.

http://home.mchsi.com/~gmvoeth/index.html

will show a bit more of what I am doing.

Buy the RS printed circuit board that has the same layout as the
breadoard. Build the circuit on that board, and put it inside of a
metal enclosure, so that most of the noise is kept out of the
circuit.

What is "RS printed circuit board " ?

RS = Radio Shack AKA Radio Scrap, etc. They sell a PC board that has
the same layout as the breadboard. Makes it easy to transfer the
circuit to a permanent circuit board.

I have settled on using only a single filter
as is now posted to my web site. This will
limit one to only seeing P waves but in
this noisy environment it is the best I can do.
I agree with everything you say except I can not
put a preamp outside with the Geophone.

Well, that's probably the reason why you are getting so much noise!

There is a circuit I have included not on the
schematic and it is a 567 tone decoder on the back
end to decode WWV calibration marks.

Thanks for your advice, I can see a lot of
common sense to it. But I still do not
know how to buy a circuit board that already
has my layout on it. I figure I will have
to do the layout and etching etc... myself.

I'm not sure you understand. The hole patterns match those on the
breadboard.
Here it is, it's catalog # 276-170 and costs a bit over $3.
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fnam
e=CTLG%5F011%5F002%5F002%5F000&product%5Fid=276%2D170&MSCSProfile=745D84
CBF04D14A48AA6FF9C89D722C0BA68C1B04FE384678A5285FCD6E056B17AF21627FDABE3
16B90B3C038D68EBD6B7F9F3BD1712EAA9951ACB2590A05C6517EFE46941FEFDD1985D4E
FD6321F5E70B4DE9B6C1D45512DCD9FB3DBCACB9479D26760FAF1D7B193B4FEA078B5E09
80BDD61634ABB7D328B012D36915420A2B457BE162481F674B


All preamplification should be done as close as possible to the
geophone, to get the signal well above the noise _before_ it goes
any
distance.

Filtering should be done at the other end, to get rid of noise in
the
long transmission line between the sensor and the PC.

One other important point. The outside can of the electrolytic is
at
signal level, and is a large capacitance to the outside world. Just
shielding these from outside noise should help. You might consider
putting some aluminum foil over the ones at the input, and grounding
the
foil to common. Just to see how much it will help to put the whole
thing in an enclosure.

[snip]

 

[bj]

"THo" <cyberhun@shaw.ca> wrote in message
news:iKqQd.398480$8l.64298@pd7tw1no...

I was given an old oscilloscope, and I'm not sure if it's working
properly.
It's a tube-based one, Tektronic 515. There's only one probe with it, and
I
connected it to a radio, and it does respond, somewhat. But when there is
no signal of any kind, the image traced on the screen isn't a moving dot,
it's more like a band, and no matter how it's adjusted the band never
moves
more than halfway across the screen. I've attached a pic of the output
when
there is no input of any kind. How abnormal is this? Is there a way to
re-calibrate it or anything like that?

Tom


No.

This is not normal. It look like a sawtooth waveform from a sweep circuit.
Sorry, I am not familiar
with this model. Does it have any built-in scope calibrator? Many of their
even cheap scopes have
a built-in square wave generator. This allows you to set the waveform
amplitude and scope probe
frequency response (capacitance). I realize that this isn't much help. Why
don't you contact
Tektronics?