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Checking capacitors...

R

Ralph Mowery

Guest
Today I received one of the roughly $ 20 component testers. Checking
it out and comparing capacitors I notices a big difference in a couple
of them

I was using a Fluke 87, a LCR meter from China, an older component
tester and the new component tester.

The first capacitor was a Sprague .06 uF 600V. Two China testers showed
near the value. Within the 10% tollorence, The LCR tester showed it
to be .08 and the Fluke as .1 uF.
This is a new,but very old capacitor.

Next capacitor was a 20 year old no name of .068 of 50 V made with the
Poly something dielectric. All meters were with in less than 10 %. Ok
here.
Same results with a newer one of .01 uF .

Next came a Silver mica. It is .01 at 600 V. Fluke shows up at .0150,
LCR at .0120. Two component testers were close and in spec.


What gives with some capacitors checking like they should and some being
way off, not just 10 % or so ? I ran the tests several times on each
capacitor to see if maybe the leads were not making good contact and any
other similar thing I may have missed like having my fingers across the
leads.

Ralph ku4pt
 
P

Phil Hobbs

Guest
On 2020-05-28 15:54, Ralph Mowery wrote:
Today I received one of the roughly $ 20 component testers. Checking
it out and comparing capacitors I notices a big difference in a couple
of them

I was using a Fluke 87, a LCR meter from China, an older component
tester and the new component tester.

The first capacitor was a Sprague .06 uF 600V. Two China testers showed
near the value. Within the 10% tollorence, The LCR tester showed it
to be .08 and the Fluke as .1 uF.
This is a new,but very old capacitor.

Next capacitor was a 20 year old no name of .068 of 50 V made with the
Poly something dielectric. All meters were with in less than 10 %. Ok
here.
Same results with a newer one of .01 uF .

Next came a Silver mica. It is .01 at 600 V. Fluke shows up at .0150,
LCR at .0120. Two component testers were close and in spec.


What gives with some capacitors checking like they should and some being
way off, not just 10 % or so ? I ran the tests several times on each
capacitor to see if maybe the leads were not making good contact and any
other similar thing I may have missed like having my fingers across the
leads.

Ralph ku4pt
Might be bad soakage--micas are horrible for that. If you stick a 1-Hz
square wave into it and look at the voltage across a the 1-M input
impedance of your scope, you might see something interesting.

Scoping what the meters are doing to the cap would be interesting too.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
P

Phil Hobbs

Guest
On 2020-05-28 15:54, Ralph Mowery wrote:
Today I received one of the roughly $ 20 component testers. Checking
it out and comparing capacitors I notices a big difference in a couple
of them

I was using a Fluke 87, a LCR meter from China, an older component
tester and the new component tester.

The first capacitor was a Sprague .06 uF 600V. Two China testers showed
near the value. Within the 10% tollorence, The LCR tester showed it
to be .08 and the Fluke as .1 uF.
This is a new,but very old capacitor.

Next capacitor was a 20 year old no name of .068 of 50 V made with the
Poly something dielectric. All meters were with in less than 10 %. Ok
here.
Same results with a newer one of .01 uF .

Next came a Silver mica. It is .01 at 600 V. Fluke shows up at .0150,
LCR at .0120. Two component testers were close and in spec.


What gives with some capacitors checking like they should and some being
way off, not just 10 % or so ? I ran the tests several times on each
capacitor to see if maybe the leads were not making good contact and any
other similar thing I may have missed like having my fingers across the
leads.

Ralph ku4pt
Might be bad soakage--micas are horrible for that. If you stick a 1-Hz
square wave into it and look at the voltage across a the 1-M input
impedance of your scope, you might see something interesting.

Scoping what the meters are doing to the cap would be interesting too.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
M

Michael Terrell

Guest
On Thursday, May 28, 2020 at 3:54:41 PM UTC-4, Ralph Mowery wrote:
Today I received one of the roughly $ 20 component testers. Checking
it out and comparing capacitors I notices a big difference in a couple
of them

I was using a Fluke 87, a LCR meter from China, an older component
tester and the new component tester.

The first capacitor was a Sprague .06 uF 600V. Two China testers showed
near the value. Within the 10% tollorence, The LCR tester showed it
to be .08 and the Fluke as .1 uF.
This is a new,but very old capacitor.

Next capacitor was a 20 year old no name of .068 of 50 V made with the
Poly something dielectric. All meters were with in less than 10 %. Ok
here.
Same results with a newer one of .01 uF .

Next came a Silver mica. It is .01 at 600 V. Fluke shows up at .0150,
LCR at .0120. Two component testers were close and in spec.


What gives with some capacitors checking like they should and some being
way off, not just 10 % or so ? I ran the tests several times on each
capacitor to see if maybe the leads were not making good contact and any
other similar thing I may have missed like having my fingers across the
leads.

Ralph ku4pt
The first two are wound, and the third is multi layer. Winding adds some inductance, if the ends are not fully bonded their entire length. That added ESL will change the reading. Silver Mica are designed for low ESR in RF applications. .01 and .06 uF are more use at lower frequencies.
 
M

Michael Terrell

Guest
On Thursday, May 28, 2020 at 3:54:41 PM UTC-4, Ralph Mowery wrote:
Today I received one of the roughly $ 20 component testers. Checking
it out and comparing capacitors I notices a big difference in a couple
of them

I was using a Fluke 87, a LCR meter from China, an older component
tester and the new component tester.

The first capacitor was a Sprague .06 uF 600V. Two China testers showed
near the value. Within the 10% tollorence, The LCR tester showed it
to be .08 and the Fluke as .1 uF.
This is a new,but very old capacitor.

Next capacitor was a 20 year old no name of .068 of 50 V made with the
Poly something dielectric. All meters were with in less than 10 %. Ok
here.
Same results with a newer one of .01 uF .

Next came a Silver mica. It is .01 at 600 V. Fluke shows up at .0150,
LCR at .0120. Two component testers were close and in spec.


What gives with some capacitors checking like they should and some being
way off, not just 10 % or so ? I ran the tests several times on each
capacitor to see if maybe the leads were not making good contact and any
other similar thing I may have missed like having my fingers across the
leads.

Ralph ku4pt
The first two are wound, and the third is multi layer. Winding adds some inductance, if the ends are not fully bonded their entire length. That added ESL will change the reading. Silver Mica are designed for low ESR in RF applications. .01 and .06 uF are more use at lower frequencies.
 
R

Ralph Mowery

Guest
In article <041d25c9-3829-9f33-f1cb-506ac85a75dd@electrooptical.net>,
pcdhSpamMeSenseless@electrooptical.net says...
I was using a Fluke 87, a LCR meter from China, an older component
tester and the new component tester.

The first capacitor was a Sprague .06 uF 600V. Two China testers showed
near the value. Within the 10% tollorence, The LCR tester showed it
to be .08 and the Fluke as .1 uF.
This is a new,but very old capacitor.

Next capacitor was a 20 year old no name of .068 of 50 V made with the
Poly something dielectric. All meters were with in less than 10 %. Ok
here.
Same results with a newer one of .01 uF .

Next came a Silver mica. It is .01 at 600 V. Fluke shows up at .0150,
LCR at .0120. Two component testers were close and in spec.


What gives with some capacitors checking like they should and some being
way off, not just 10 % or so ? I ran the tests several times on each
capacitor to see if maybe the leads were not making good contact and any
other similar thing I may have missed like having my fingers across the
leads.

Ralph ku4pt


Might be bad soakage--micas are horrible for that. If you stick a 1-Hz
square wave into it and look at the voltage across a the 1-M input
impedance of your scope, you might see something interesting.

Scoping what the meters are doing to the cap would be interesting too.
I have a decent test bench. Not lab quality,but not too bad.

I hooked a function generator set as square waves to 2 1000 ohm
resistors for isolation. From each resistor I went to a capacitor. One
was the Sprague and the other was the poly something capacitor. Then
back to the ground side of the generator.

A dual track Hanteck 200 mhz scope with 10:1 probes were hooked across
the capacitors. I started out at .1 Hz and went up to around 10,000 Hz.
At all times the traces were almost identical. They started out as
almost perfect square waves as expected . At a couple of hundred cycles
the leading edge started to show a rounding off near the rise of the
cycle (top of the trace) and same for the negative part of the cycle.
As I increased the frequency they started resembling sine waves. About
like I expected. At no time was there any measurable difference in the
waveformes.

I measured them again on the capacitor checkers and same results. The
poly capacitor was very close on the meters and the Spraque was showing
..1 instead of .06 or close to .06 on hte Fluke and .08 on another
tester. Had it shown .07 or .05 I would have called it meter tollorance
but not almost double.


I don\'t have a capacitor tester that I can put any high voltage on them
like 500 or so volts.

When I have more time I may try scoping the meters and see what they are
putting across the capacitors.
 
R

Ralph Mowery

Guest
In article <041d25c9-3829-9f33-f1cb-506ac85a75dd@electrooptical.net>,
pcdhSpamMeSenseless@electrooptical.net says...
I was using a Fluke 87, a LCR meter from China, an older component
tester and the new component tester.

The first capacitor was a Sprague .06 uF 600V. Two China testers showed
near the value. Within the 10% tollorence, The LCR tester showed it
to be .08 and the Fluke as .1 uF.
This is a new,but very old capacitor.

Next capacitor was a 20 year old no name of .068 of 50 V made with the
Poly something dielectric. All meters were with in less than 10 %. Ok
here.
Same results with a newer one of .01 uF .

Next came a Silver mica. It is .01 at 600 V. Fluke shows up at .0150,
LCR at .0120. Two component testers were close and in spec.


What gives with some capacitors checking like they should and some being
way off, not just 10 % or so ? I ran the tests several times on each
capacitor to see if maybe the leads were not making good contact and any
other similar thing I may have missed like having my fingers across the
leads.

Ralph ku4pt


Might be bad soakage--micas are horrible for that. If you stick a 1-Hz
square wave into it and look at the voltage across a the 1-M input
impedance of your scope, you might see something interesting.

Scoping what the meters are doing to the cap would be interesting too.
I have a decent test bench. Not lab quality,but not too bad.

I hooked a function generator set as square waves to 2 1000 ohm
resistors for isolation. From each resistor I went to a capacitor. One
was the Sprague and the other was the poly something capacitor. Then
back to the ground side of the generator.

A dual track Hanteck 200 mhz scope with 10:1 probes were hooked across
the capacitors. I started out at .1 Hz and went up to around 10,000 Hz.
At all times the traces were almost identical. They started out as
almost perfect square waves as expected . At a couple of hundred cycles
the leading edge started to show a rounding off near the rise of the
cycle (top of the trace) and same for the negative part of the cycle.
As I increased the frequency they started resembling sine waves. About
like I expected. At no time was there any measurable difference in the
waveformes.

I measured them again on the capacitor checkers and same results. The
poly capacitor was very close on the meters and the Spraque was showing
..1 instead of .06 or close to .06 on hte Fluke and .08 on another
tester. Had it shown .07 or .05 I would have called it meter tollorance
but not almost double.


I don\'t have a capacitor tester that I can put any high voltage on them
like 500 or so volts.

When I have more time I may try scoping the meters and see what they are
putting across the capacitors.
 
P

Phil Hobbs

Guest
On 2020-05-28 17:48, Ralph Mowery wrote:
In article <041d25c9-3829-9f33-f1cb-506ac85a75dd@electrooptical.net>,
pcdhSpamMeSenseless@electrooptical.net says...

I was using a Fluke 87, a LCR meter from China, an older component
tester and the new component tester.

The first capacitor was a Sprague .06 uF 600V. Two China testers showed
near the value. Within the 10% tollorence, The LCR tester showed it
to be .08 and the Fluke as .1 uF.
This is a new,but very old capacitor.

Next capacitor was a 20 year old no name of .068 of 50 V made with the
Poly something dielectric. All meters were with in less than 10 %. Ok
here.
Same results with a newer one of .01 uF .

Next came a Silver mica. It is .01 at 600 V. Fluke shows up at .0150,
LCR at .0120. Two component testers were close and in spec.


What gives with some capacitors checking like they should and some being
way off, not just 10 % or so ? I ran the tests several times on each
capacitor to see if maybe the leads were not making good contact and any
other similar thing I may have missed like having my fingers across the
leads.

Ralph ku4pt


Might be bad soakage--micas are horrible for that. If you stick a 1-Hz
square wave into it and look at the voltage across a the 1-M input
impedance of your scope, you might see something interesting.

Scoping what the meters are doing to the cap would be interesting too.




I have a decent test bench. Not lab quality,but not too bad.

I hooked a function generator set as square waves to 2 1000 ohm
resistors for isolation. From each resistor I went to a capacitor. One
was the Sprague and the other was the poly something capacitor. Then
back to the ground side of the generator.

A dual track Hanteck 200 mhz scope with 10:1 probes were hooked across
the capacitors. I started out at .1 Hz and went up to around 10,000 Hz.
At all times the traces were almost identical. They started out as
almost perfect square waves as expected . At a couple of hundred cycles
the leading edge started to show a rounding off near the rise of the
cycle (top of the trace) and same for the negative part of the cycle.
As I increased the frequency they started resembling sine waves. About
like I expected. At no time was there any measurable difference in the
waveformes.
My suggestion was to look at the current through the capacitors going
into a high impedance. That way you don\'t load down the generator.
I measured them again on the capacitor checkers and same results. The
poly capacitor was very close on the meters and the Spraque was showing
.1 instead of .06 or close to .06 on hte Fluke and .08 on another
tester. Had it shown .07 or .05 I would have called it meter tollorance
but not almost double.


I don\'t have a capacitor tester that I can put any high voltage on them
like 500 or so volts.

When I have more time I may try scoping the meters and see what they are
putting across the capacitors.
Hmm, dunno. The meters may be using different schemes.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
P

Phil Allison

Guest
Ralph Mowery wrote:

================
I hooked a function generator set as square waves to 2 1000 ohm
resistors for isolation. From each resistor I went to a capacitor. One
was the Sprague and the other was the poly something capacitor. Then
back to the ground side of the generator.

A dual track Hanteck 200 mhz scope with 10:1 probes were hooked across
the capacitors. I started out at .1 Hz and went up to around 10,000 Hz.
At all times the traces were almost identical. They started out as
almost perfect square waves as expected . At a couple of hundred cycles
the leading edge started to show a rounding off near the rise of the
cycle (top of the trace) and same for the negative part of the cycle.
As I increased the frequency they started resembling sine waves.


** That does *NOT* happen !!!!
With square wave input, a simple RC filer converts the wave to a TRIANGLE shape if the frequency is high.

Your ancient Sprague ( Black Beauty ?) is almost certainly leaky due to moisture ingress.

A DMM on ohms should show you that.

Forget Terrell\'s nonsense about wound and non wound cops - he is just blowing it out his arse as usual.



..... Phil
 
P

Phil Allison

Guest
Ralph Mowery wrote:

================
I hooked a function generator set as square waves to 2 1000 ohm
resistors for isolation. From each resistor I went to a capacitor. One
was the Sprague and the other was the poly something capacitor. Then
back to the ground side of the generator.

A dual track Hanteck 200 mhz scope with 10:1 probes were hooked across
the capacitors. I started out at .1 Hz and went up to around 10,000 Hz.
At all times the traces were almost identical. They started out as
almost perfect square waves as expected . At a couple of hundred cycles
the leading edge started to show a rounding off near the rise of the
cycle (top of the trace) and same for the negative part of the cycle.
As I increased the frequency they started resembling sine waves.


** That does *NOT* happen !!!!
With square wave input, a simple RC filer converts the wave to a TRIANGLE shape if the frequency is high.

Your ancient Sprague ( Black Beauty ?) is almost certainly leaky due to moisture ingress.

A DMM on ohms should show you that.

Forget Terrell\'s nonsense about wound and non wound cops - he is just blowing it out his arse as usual.



..... Phil
 
M

Michael Terrell

Guest
On Friday, May 29, 2020 at 12:05:38 AM UTC-4, Phil Allison wrote:
Ralph Mowery wrote:

===============

I hooked a function generator set as square waves to 2 1000 ohm
resistors for isolation. From each resistor I went to a capacitor. One
was the Sprague and the other was the poly something capacitor. Then
back to the ground side of the generator.

A dual track Hanteck 200 mhz scope with 10:1 probes were hooked across
the capacitors. I started out at .1 Hz and went up to around 10,000 Hz..
At all times the traces were almost identical. They started out as
almost perfect square waves as expected . At a couple of hundred cycles
the leading edge started to show a rounding off near the rise of the
cycle (top of the trace) and same for the negative part of the cycle.
As I increased the frequency they started resembling sine waves.


** That does *NOT* happen !!!!

With square wave input, a simple RC filer converts the wave to a TRIANGLE shape if the frequency is high.

Your ancient Sprague ( Black Beauty ?) is almost certainly leaky due to moisture ingress.

A DMM on ohms should show you that.

Forget Terrell\'s nonsense about wound and non wound cops - he is just blowing it out his arse as usual.
Yawn. You are clueless about ESL, SRF and other REAL factors once you are above audio. NO component is perfect, and there are valid reasons. Different construction methods have different effects on their performance as well as heir failure mode. SM fails due to Silver Migration which causes them to short. Film capacitors pinhole, and short. Electrolytics have many failure modes, but they are the cheapest to manufacture. SM is one of the most expensive, but they can handle higher RF current that ceramics of the same ratings. I\'ll listen to you, when you have decades of high power RF work to your sorry name. All capacitors will fail, in time. Even Vacuum capacitors fail. The problem is choosing the right class for a design.
 
M

Michael Terrell

Guest
On Friday, May 29, 2020 at 12:05:38 AM UTC-4, Phil Allison wrote:
Ralph Mowery wrote:

===============

I hooked a function generator set as square waves to 2 1000 ohm
resistors for isolation. From each resistor I went to a capacitor. One
was the Sprague and the other was the poly something capacitor. Then
back to the ground side of the generator.

A dual track Hanteck 200 mhz scope with 10:1 probes were hooked across
the capacitors. I started out at .1 Hz and went up to around 10,000 Hz..
At all times the traces were almost identical. They started out as
almost perfect square waves as expected . At a couple of hundred cycles
the leading edge started to show a rounding off near the rise of the
cycle (top of the trace) and same for the negative part of the cycle.
As I increased the frequency they started resembling sine waves.


** That does *NOT* happen !!!!

With square wave input, a simple RC filer converts the wave to a TRIANGLE shape if the frequency is high.

Your ancient Sprague ( Black Beauty ?) is almost certainly leaky due to moisture ingress.

A DMM on ohms should show you that.

Forget Terrell\'s nonsense about wound and non wound cops - he is just blowing it out his arse as usual.
Yawn. You are clueless about ESL, SRF and other REAL factors once you are above audio. NO component is perfect, and there are valid reasons. Different construction methods have different effects on their performance as well as heir failure mode. SM fails due to Silver Migration which causes them to short. Film capacitors pinhole, and short. Electrolytics have many failure modes, but they are the cheapest to manufacture. SM is one of the most expensive, but they can handle higher RF current that ceramics of the same ratings. I\'ll listen to you, when you have decades of high power RF work to your sorry name. All capacitors will fail, in time. Even Vacuum capacitors fail. The problem is choosing the right class for a design.
 
P

Phil Allison

Guest
Michael Terrell is an IDIOT wrote:

======================================
Forget Terrell\'s nonsense about wound and non wound cops -
he is just blowing it out his arse as usual.


Yawn.
** Peeeeukee........



You are clueless about ESL,
** LOL- pot calls kettle.



SRF and other REAL factors once you are above audio.
** ROTFL - there is nothing like a pig ignorant fool making wild guesses.


FYI - fuckhead, I am very well aware of the technical issues surrounding capacitors and their many failure modes too. You have no fucking idea what I know or do not.

What you ACTUALLY posted was total idiocy and I see you now make NO reference to it whatsoever. Nicely proving my point.

Thank you - you fucking asshole



...... Phil






...... Phil
 
P

Phil Allison

Guest
Michael Terrell is an IDIOT wrote:

======================================
Forget Terrell\'s nonsense about wound and non wound cops -
he is just blowing it out his arse as usual.


Yawn.
** Peeeeukee........



You are clueless about ESL,
** LOL- pot calls kettle.



SRF and other REAL factors once you are above audio.
** ROTFL - there is nothing like a pig ignorant fool making wild guesses.


FYI - fuckhead, I am very well aware of the technical issues surrounding capacitors and their many failure modes too. You have no fucking idea what I know or do not.

What you ACTUALLY posted was total idiocy and I see you now make NO reference to it whatsoever. Nicely proving my point.

Thank you - you fucking asshole



...... Phil






...... Phil
 
R

Ralph Mowery

Guest
In article <0c45e822-10bb-469e-b44d-8b7e319d58e4@googlegroups.com>,
pallison49@gmail.com says...
cycle (top of the trace) and same for the negative part of the cycle.
As I increased the frequency they started resembling sine waves.


** That does *NOT* happen !!!!

With square wave input, a simple RC filer converts the wave to a TRIANGLE shape if the frequency is high.

Your ancient Sprague ( Black Beauty ?) is almost certainly leaky due to moisture ingress.

A DMM on ohms should show you that.
When I said resembled sine waves, I knew they were not really sine,but
did not crank the sweep far enough to see what they actually were. It
has been a while back that I did any thing with what circuit converts
what, but did remember that LC low pass filters converted to the sine
wave.

The Sprague is not the Black Beauty lable. I think it is the next
generation, but not sure. I don\'t recall the value, but at 500 volts dc
it had less than .1 ma leakage. It did surprise me that it did not
have a lot of leakage.
 
M

Michael Terrell

Guest
On Sunday, May 31, 2020 at 6:28:37 AM UTC-4, Phil Allison wrote absolutely nothing:


Do you have bad case of PMS, Phyllis?
 
P

Phil Allison

Guest
Ralph Mowery wrote:

=====================

** That does *NOT* happen !!!!

With square wave input, a simple RC filer converts the wave to a TRIANGLE shape if the frequency is high.

Your ancient Sprague ( Black Beauty ?) is almost certainly leaky due to moisture ingress.

A DMM on ohms should show you that.



When I said resembled sine waves, I knew they were not really sine,but
did not crank the sweep far enough to see what they actually were. It
has been a while back that I did any thing with what circuit converts
what, but did remember that LC low pass filters converted to the sine
wave.
** Yes, cos they filter with a -12dB/octave slope wiping out all the harmionic of a square wave.

The Sprague is not the Black Beauty lable. I think it is the next
generation, but not sure. I don\'t recall the value, but at 500 volts dc
it had less than .1 ma leakage. It did surprise me that it did not
have a lot of leakage.
** Equates to 5M ohms so would fully self discharge in about 1 second.

( 5exp6 times 0.06exp-6 = 0.3 seconds )

Easily enough to upset many capacitance meters.

A good film cap of such value has a R value in the Gohm range and leakage under 1uA.


..... Phil




...... Phil
 
R

Ralph Mowery

Guest
In article <0c45e822-10bb-469e-b44d-8b7e319d58e4@googlegroups.com>,
pallison49@gmail.com says...
cycle (top of the trace) and same for the negative part of the cycle.
As I increased the frequency they started resembling sine waves.


** That does *NOT* happen !!!!

With square wave input, a simple RC filer converts the wave to a TRIANGLE shape if the frequency is high.

Your ancient Sprague ( Black Beauty ?) is almost certainly leaky due to moisture ingress.

A DMM on ohms should show you that.
When I said resembled sine waves, I knew they were not really sine,but
did not crank the sweep far enough to see what they actually were. It
has been a while back that I did any thing with what circuit converts
what, but did remember that LC low pass filters converted to the sine
wave.

The Sprague is not the Black Beauty lable. I think it is the next
generation, but not sure. I don\'t recall the value, but at 500 volts dc
it had less than .1 ma leakage. It did surprise me that it did not
have a lot of leakage.
 
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