Elektor Electronics
Eric
http://213.222.12.205/Default.aspx?tabid=27&year=2005&month=9&art=52895&PN=O
n
Hopeless NZ bookshops have not put it on the shelf yet,
Does anyone know what capacitors range the ESR meter does?
Phil Allison
"Eric the Kiwi"
> Anyone get Elektor Electronics magazine
** A waste of perfectly good trees.
> Hopeless NZ bookshops have not put it on the shelf yet,
** Trees 1, Elektor 0.
> Does anyone know what capacitors range the ESR meter does?
** Who bloody cares ??
Every second DMM on sale measures capacitance well enough.
For PSU electros an ESR meter is all you need and Bob Parker's one is a
winner.
If an electro passes the ESR test - then it has its original (marked)
capacitance value.
If an electro fails the ESR test - then it goes straight in the bin.
Capice ?
......... Phil
The Real Andy
<phila...@tpg.com.au> wrote:
>
>"Eric the Kiwi"
>
>> Anyone get Elektor Electronics magazine
>
>** A waste of perfectly good trees.
>
Why is that Phil? Is it because the dont publish designs based on
pre-historic components?
Perhaps the ex roadies dont like mags that publish mostly digital
designs
<snip>
Tom
> On Sun, 11 Sep 2005 13:11:45 +1000, "Phil Allison"
> <phila...@tpg.com.au> wrote:
>
>
>>"Eric the Kiwi"
>>
>>
>>>Anyone get Elektor Electronics magazine
>>
>>** A waste of perfectly good trees.
>>
>
>
> Why is that Phil? Is it because the dont publish designs based on
> pre-historic components?
Because you can get same thing in a pdf
Eric
answer, just pathic replys from children that have nothing better to do"
Phil Allison
"Eric"
> Now why did I think as I wrote the question, "I would most unlikely get a
> answer, just pathic replys from children that have nothing better to do"
>
** YOU are a fucking, PITA **TROLL** - eric.
Go check the Auckland phone book for typos - if you can stand the
excitement.
.......... Phil
Franc Zabkar
to keyboard and composed:
With respect, I can't see that this question makes any sense. An ESR
meter measures ESR, not capacitance. Ideally the capacitor's C should
not affect the result because it should look like a S/C to the test
signal.
I don't know anything about the Elektor meter, but Bob Parker's meter
applies charging pulses of three different amplitudes to the capacitor
under test, and then compares the voltage to an internal reference
capacitor. The assumption is that the pulse is of sufficently short
duration so as not to appreciably charge the test capacitor. AFAICS,
the larger the cap, the more accurate the measurement. As for very
small caps, I would think that the meter's internal time constants
would be selected so as to accommodate the smallest expected values of
capacitance. At the very worst, the meter would overestimate the ESR.
In this case the user could check the reading against a known good cap
of the same value.
-- Franc Zabkar
Please remove one 'i' from my address when replying by email.
The Real Andy
For an individual with such a pathetic existance, you still manage to
extract a chuckle from me phil...
The Real Andy
>Now why did I think as I wrote the question, "I would most unlikely get a
>answer, just pathic replys from children that have nothing better to do"
>
This is aus.e;ectronics, and it does reflect the nature of the
industry in australia :)
I used to be an elektor subscriber and they continue to send me mags.
If this one turns up in the post I will email you.
quietguy
range of caps they can accurately check for ESR - especially at the lower end of
the range I gather
David
Franc Zabkar wrote:
> On Sun, 11 Sep 2005 08:42:14 +1200, "Eric" <er...@home.net> put finger
> to keyboard and composed:
> >
Franc Zabkar
<quie...@REMOVE-TO-REPLYconfidential-counselling.com> put finger to
keyboard and composed:
>Looking at a review of ESR meters I note that they do vary in respect of the
>range of caps they can accurately check for ESR - especially at the lower end of
>the range I gather
>
>David
Well, that's what I expected in the worst case.
Anyway, I notice that the ESR table on Bob Parker's Mark 1 meter goes
down to 1uF, so I tried the following test using five Hitano EXR
series 105 degC 1uF 100V low ESR electrolytics (WES code 1EXR100).
individual ESR measurements (1uF): 3.1, 3.3, 3.6, 3.8, 3.8 ohms
all five in series (0.2uF): 18 ohms
all five in parallel (5uF): 0.67 ohms
The results suggest that the meter is reasonably linear in the range
0.2uF - 5uF.
The next readings are for used, 250V, film, mains rated X2 caps:
C (uF) ESR (ohms)
-----------------------
1.0 1.4 1.4
0.82 1.5 1.5
0.47 3.3 2.9 3.5
0.22 7.7
0.10 19 19
I would have thought that the ESR for this type of cap was negligible
(< 0.5 ohm ???). If so, then the readings must reflect the
capacitance's contribution to the measurement process. If I understand
Bob's design correctly, the capacitance should contribute a
"resistance" value of dt/C (= dV/Ipulse), where dt is the duration of
the charging pulse. For example, a 1us pulse into an ideal 1uF cap
should make it test like a 1 ohm resistance, whereas an 0.1uF cap
would measure 10 ohms.
>Franc Zabkar wrote:
>
>> On Sun, 11 Sep 2005 08:42:14 +1200, "Eric" <er...@home.net> put finger
>> to keyboard and composed:
>> >
>> >Does anyone know what capacitors range the ESR meter does?
>>
>> With respect, I can't see that this question makes any sense. An ESR
>> meter measures ESR, not capacitance. Ideally the capacitor's C should
>> not affect the result because it should look like a S/C to the test
>> signal.
>>
-- Franc Zabkar
Phil Allison
"Franc Zabkar"
quietguy
>
>>Looking at a review of ESR meters I note that they do vary in respect of
>>the
>>range of caps they can accurately check for ESR - especially at the lower
>>end of
>>the range I gather
>>
>
> down to 1uF, so I tried the following test using five Hitano EXR
> series 105 degC 1uF 100V low ESR electrolytics (WES code 1EXR100).
>
> individual ESR measurements (1uF): 3.1, 3.3, 3.6, 3.8, 3.8 ohms
> all five in series (0.2uF): 18 ohms
> all five in parallel (5uF): 0.67 ohms
>
> The results suggest that the meter is reasonably linear in the range
> 0.2uF - 5uF.
>
> The next readings are for used, 250V, film, mains rated X2 caps:
>
> C (uF) ESR (ohms)
> -----------------------
> 1.0 1.4 1.4
> 0.82 1.5 1.5
> 0.47 3.3 2.9 3.5
> 0.22 7.7
> 0.10 19 19
>
> I would have thought that the ESR for this type of cap was negligible
> (< 0.5 ohm ???). If so, then the readings must reflect the
> capacitance's contribution to the measurement process. If I understand
> Bob's design correctly, the capacitance should contribute a
> "resistance" value of dt/C (= dV/Ipulse), where dt is the duration of
> the charging pulse. For example, a 1us pulse into an ideal 1uF cap
> should make it test like a 1 ohm resistance, whereas an 0.1uF cap
> would measure 10 ohms.
>
** Bob's brilliant ESR meter is very clearly intended to test ** ELECTROS
** - while in circuit, in faulty gear !!
The whole reason for testing the electros is because at the end of their
useful life, the " juice " inside dries out sending the ESR value high.
The principle of operation relies on the fact that at a frequency of about
100kHz, an electro's impedance it at its minimum value - so nearly equal
to the intrinsic internal resistance or ESR !!
Very low value electros, like 1 uF, need a slightly higher test frequency
for best accuracy.
However, plastic film capacitors need to be tested from 1 to 10 MHz to find
their true ESR values - only a variable frequency ESR meter could do that
as you need to find the series resonance .
Film caps do not vary in ESR throughout their life - so no need for such
testing exists.
......... Phil
S Roby
>On Wed, 14 Sep 2005 23:57:28 GMT, quietguy
><quie...@REMOVE-TO-REPLYconfidential-counselling.com> put finger to
>keyboard and composed:
>
>>Looking at a review of ESR meters I note that they do vary in respect of the
>>range of caps they can accurately check for ESR - especially at the lower end
> of
>>the range I gather
>>
>>David
>
>Well, that's what I expected in the worst case.
>
>Anyway, I notice that the ESR table on Bob Parker's Mark 1 meter goes
>down to 1uF, so I tried the following test using five Hitano EXR
>series 105 degC 1uF 100V low ESR electrolytics (WES code 1EXR100).
>
Ive tested faulty electro caps which still give a 'pass' according to the
table. Ive also got some caps quite visibly leaking & buldging that test
'ok 'with my ESR & a CAP meter.
Just something to bear in mind for amatures (like me).
Phil Allison
"S Roby"
>
> Ive tested faulty electro caps which still give a 'pass' according to the
> table.
** What make you sure they were faulty then ??
> I've also got some caps quite visibly leaking & buldging that test
> 'ok 'with my ESR & a CAP meter.
** So they were electrically OK - but visual reasons existed to replace
them .
............. Phil
S Roby
>
>"S Roby"
>
>>
>> Ive tested faulty electro caps which still give a 'pass' according to the
>> table.
>
>** What make you sure they were faulty then ??
>
The tech at work pulled them out(replaced them) to fix power supplies.
Phil Allison
"S Roby"
"Phil Allison"
>>
>>> Ive tested faulty electro caps which still give a 'pass' according to
>>> the
>>> table.
>>
>>** What make you sure they were faulty then ??
>>
>
> The tech at work pulled them out(replaced them) to fix power supplies.
>
** I repeat:
What make you sure they were faulty then ??
The tech may have replaced them as a precaution or because they were of a
certain age etc.
........... Phil
Bob Parker
you with 100% accuracy which capacitors are defective. They're just
one more test instrument which tells an experienced user with a good
knowledge of electronics about another characteristic of capacitors
which is very relevant to how well they're doing their job. ESR meter
readings have to be intelligently combined with other factors
including the physical state of the capacitor being tested.
I never cease to be amazed by how little electrical knowledge many
ESR meter users have. The DSE meter was designed specifically for
service technicians, but many of them have been bought by hobbisyts
and "amatures", a lot of whom still seem to think that ESR equates to
leakage and/or that the higher the ESR the better.
I agree with Phil's comments... he understands and appreciates
where ESR meters fit into the overall scheme of things. :)
That's my 2c worth.
Cheers
Bob
Franc Zabkar
<phila...@tpg.com.au> put finger to keyboard and composed:
>The principle of operation relies on the fact that at a frequency of about
>100kHz, an electro's impedance it at its minimum value - so nearly equal
>to the intrinsic internal resistance or ESR !!
The test signal is not sinusoidal. While the Xc of a 1uF cap at 100kHz
is a negligible 1.6 ohms, that is not what the meter sees. The test
signal, at least for the Mark 2 version, is an 8us current pulse with
a frequency of 2kHz. The voltage seen at the meter's terminals would
be given by ...
V = (I * R) + (I * dt/C)
The meter assumes it is seeing a pure resistance (R'), so it applies
Ohm's Law and comes up with ...
R' = V/I
= R + dt/C
This reduces to R' = R + 8 in the above case.
So if one were to apply the design principle described by Bob in his
SC article, one would expect the meter to read 8 ohms for a perfect
1uF capacitance. This is not what I observe in practice, but it may at
least partly explain the higher than expected readings for the film
caps.
Franc Zabkar
>"Franc Zabkar"
>> The next readings are for used, 250V, film, mains rated X2 caps:
>>
>> C (uF) ESR (ohms)
>> -----------------------
>> 1.0 1.4 1.4
>> 0.82 1.5 1.5
>> 0.47 3.3 2.9 3.5
>> 0.22 7.7
>> 0.10 19 19
>>
>> I would have thought that the ESR for this type of cap was negligible
>> (< 0.5 ohm ???). If so, then the readings must reflect the
>> capacitance's contribution to the measurement process.
>However, plastic film capacitors need to be tested from 1 to 10 MHz to find
>their true ESR values - only a variable frequency ESR meter could do that
>as you need to find the series resonance .
>Film caps do not vary in ESR throughout their life - so no need for such
>testing exists.
I did not suggest that such testing was required. I merely wanted to
see how the meter would evaluate "perfect" caps. To paraphrase Dirty
Harry, a man's gotta know his test equipment's limitations.
Regardless, manufacturers quote a loss tangent figure for these types
of caps.
See this datasheet:
http://www.vishay.com/docs/28119/mkp3382.pdf
Tangent of loss angle at 1 kHz 10 kHz 100 kHz
----------------------------------------------------
C <= 470 nF 0.001 0.002 0.010
The loss tangent is given by:
tan d = 2pi * f * C * R
So R (in ohms) in the above three cases for an 0.47uF film cap is as
follows:
R at 1 kHz 10 kHz 100 kHz
---------------------------------
0.34 0.068 0.034
S Roby
>** I repeat:
>
>What make you sure they were faulty then ??
I repeat
The tech at work pulled them out(replaced them) to fix power supplies.
The power supplies had spikes on the output (clearly seen on the scope) ,
fixed by replacing caps.
Phil Allison
"Franc Zabkar"
"Phil Allison"
>
>
>>The principle of operation relies on the fact that at a frequency of about
>>100kHz, an electro's impedance it at its minimum value - so nearly
>>equal
>>to the intrinsic internal resistance or ESR !!
>
>
> The test signal is not sinusoidal.
** No need to be, since the impedance minimum of an electro has a very
broad range.
> While the Xc of a 1uF cap at 100kHz
> is a negligible 1.6 ohms, that is not what the meter sees.
** 1.6 ohms is very far from negligible for a film cap.
It is, however, what the ESR meter reads with a 1uF film cap.
> The test
> signal, at least for the Mark 2 version, is an 8us current pulse with
> a frequency of 2kHz.
** It is an coupled AC signal, remember.
............. Phil
Phil Allison
"Franc Zabkar"
"Phil Allison"
>
>>> The next readings are for used, 250V, film, mains rated X2 caps:
>>>
>>> C (uF) ESR (ohms)
>>> -----------------------
>>> 1.0 1.4 1.4
>>> 0.82 1.5 1.5
>>> 0.47 3.3 2.9 3.5
>>> 0.22 7.7
>>> 0.10 19 19
>>>
>>> I would have thought that the ESR for this type of cap was negligible
>>> (< 0.5 ohm ???). If so, then the readings must reflect the
>>> capacitance's contribution to the measurement process.
>
>
>>However, plastic film capacitors need to be tested from 1 to 10 MHz to
>>find
>>their true ESR values - only a variable frequency ESR meter could do
>>that
>>as you need to find the series resonance .
>
>>Film caps do not vary in ESR throughout their life - so no need for such
>>testing exists.
>
> I did not suggest that such testing was required.
** That is a tedious irrelevance.
The fact explains why Bob's ERS meter is set up to test electros ONLY.
It is NOT, repeat NOT , a precision ESR tester.
-------------------------------------------------------------
> I merely wanted to
> see how the meter would evaluate "perfect" caps.
** Another tedious irrelevance.
Bob's ESR meter is clearly stated to be ONLY for electros.
Its only job is to pick out the ones that have gone bad in service.
-------------------------------------------------------------
> Regardless, manufacturers quote a loss tangent figure for these types
> of caps.
>
> See this datasheet:
> http://www.vishay.com/docs/28119/mkp3382.pdf
>
> Tangent of loss angle at 1 kHz 10 kHz 100 kHz
> ----------------------------------------------------
> C <= 470 nF 0.001 0.002 0.010
>
> The loss tangent is given by:
>
> tan d = 2pi * f * C * R
>
> So R (in ohms) in the above three cases for an 0.47uF film cap is as
> follows:
>
> R at 1 kHz 10 kHz 100 kHz
> ---------------------------------
> 0.34 0.068 0.034
>
** More tedious bloody irrelevances.
BTW The result figures are jumbled.
What a colossal , pedantic PITA you are Zabkar.
....... Phil
Phil Allison
"S Roby" <
** So the new caps simply had a lower ESR than the old ones.
The variation in ESR values for electro caps of the same nominal value is
quite wide.
Did you bother to compare the old and new to see the difference ???
........ Phil
Franc Zabkar
<phila...@tpg.com.au> put finger to keyboard and composed:
>
>"Franc Zabkar"
> "Phil Allison"
>>
>>
>>>The principle of operation relies on the fact that at a frequency of about
>>>100kHz, an electro's impedance it at its minimum value - so nearly
>>>equal
>>>to the intrinsic internal resistance or ESR !!
>>
>>
>> The test signal is not sinusoidal.
>
>
> ** No need to be, since the impedance minimum of an electro has a very
>broad range.
Whether or not the test signal needs to be sinusoidal is irrelevant.
The fact is that it isn't. It is in fact an 8us 2kHz *pulse*. The
principle of operation of the meter involves driving such a pulse into
a pure C in series with a pure R. A discussion of a real capacitor's
performance at 100kHz is just pointless obfuscation.
All you need to know is that I = C * dV/dt. From this it follows that
a constant current produces a voltage ramp.
That's elementary circuit theory. Quite simple really.
>> While the Xc of a 1uF cap at 100kHz
>> is a negligible 1.6 ohms, that is not what the meter sees.
>
>
> ** 1.6 ohms is very far from negligible for a film cap.
Irrelevant. You were referring to electros. Anyway, nobody cares about
the behaviour of the test cap at 100kHz.
> It is, however, what the ESR meter reads with a 1uF film cap.
The meter does not read Xc. It reads *ESR*, or at least it thinks it
does. In any case, the fact that the reading is "far from negligible"
for a "pure" capacitance demonstrates that the meter has limitations,
albeit acceptable ones, which was essentially the point of the OP's
question.
>> The test
>> signal, at least for the Mark 2 version, is an 8us current pulse with
>> a frequency of 2kHz.
>
>
> ** It is an coupled AC signal, remember.
Capacitors C5 and C6 have no effect since they are in series with a
current source.
Capacitor C7 also has no impact because the input impedance of the
meter (neglecting R23) is appropriately high.
You can quite easily calculate the expected degradation of the pulse
at the junction of C7 and R12. Assume you are testing a pure resistor,
and that it produces a voltage, Vt, at the meter's test leads.
The voltage developed across C7 by the test pulse would be:
dV = Iin . dt / C7
where Iin is the current flowing through C7 and R12.
Now the impedance looking into the junction of R13 and R14 is 69K.
This gives:
Iin = Vt / 69K
So the degradation, dV, of the pulse, Vt, is given by:
dV/Vt = (Vt /69K) . (dt / C7) / Vt
= 8us /(69K . 33nF)
= 0.35%
Hardly worth worrying about.
Franc Zabkar
<phila...@tpg.com.au> put finger to keyboard and composed:
>
>"Franc Zabkar"
> "Phil Allison"
>>
>>>> The next readings are for used, 250V, film, mains rated X2 caps:
>>>>
>>>> C (uF) ESR (ohms)
>>>> -----------------------
>>>> 1.0 1.4 1.4
>>>> 0.82 1.5 1.5
>>>> 0.47 3.3 2.9 3.5
>>>> 0.22 7.7
>>>> 0.10 19 19
>>>>
>>>> I would have thought that the ESR for this type of cap was negligible
>>>> (< 0.5 ohm ???). If so, then the readings must reflect the
>>>> capacitance's contribution to the measurement process.
>>
>>
>>>However, plastic film capacitors need to be tested from 1 to 10 MHz to
>>>find
>>>their true ESR values - only a variable frequency ESR meter could do
>>>that
>>>as you need to find the series resonance .
>>
>>>Film caps do not vary in ESR throughout their life - so no need for such
>>>testing exists.
>>
>> I did not suggest that such testing was required.
>
>
> ** That is a tedious irrelevance.
>
>The fact explains why Bob's ERS meter is set up to test electros ONLY.
>
> It is NOT, repeat NOT , a precision ESR tester.
>> I merely wanted to
>> see how the meter would evaluate "perfect" caps.
>
>
>** Another tedious irrelevance.
>Bob's ESR meter is clearly stated to be ONLY for electros.
Using a "perfect" cap demonstrates how the meter responds to the C
component in a real cap. The designer's assumption is that the C
component does not contribute significantly to the measurement
process. This is demonstrably true for 1uF caps, but not for smaller
ones.
>Its only job is to pick out the ones that have gone bad in service.
The OP wanted to know the range of an ESR meter. I answered the
question, both by actual testing, and by analysis of the design
methodology.
>> Regardless, manufacturers quote a loss tangent figure for these types
>> of caps.
>>
>> See this datasheet:
>> http://www.vishay.com/docs/28119/mkp3382.pdf
>>
>> Tangent of loss angle at 1 kHz 10 kHz 100 kHz
>> ----------------------------------------------------
>> C <= 470 nF 0.001 0.002 0.010
>>
>> The loss tangent is given by:
>>
>> tan d = 2pi * f * C * R
>>
>> So R (in ohms) in the above three cases for an 0.47uF film cap is as
>> follows:
>>
>> R at 1 kHz 10 kHz 100 kHz
>> ---------------------------------
>> 0.34 0.068 0.034
>>
>
>
>
>** More tedious bloody irrelevances.
> BTW The result figures are jumbled.
Nope. Read the datasheet and apply the formula. If you still don't
like the result, then complain to the manufacturer. Maybe he will give
a damn. I don't.
> What a colossal , pedantic PITA you are Zabkar.
The OP's question was in regard to the *limits* of measurement of the
ESR meter. In the absence of explicit specs from the manufacturer or
designer, the answer to such a question requires an understanding of
the measurement process ... or access to perfect caps. Therefore, the
question of itself *demands* a pedantic answer.
Phil Allison
"Franc Zabkar"
"Phil Allison"
>>
>>>>The principle of operation relies on the fact that at a frequency of
>>>>about
>>>>100kHz, an electro's impedance it at its minimum value - so nearly
>>>>equal to the intrinsic internal resistance or ESR !!
>>>
>>>
>>> The test signal is not sinusoidal.
>>
>>
>> ** No need to be, since the impedance minimum of an electro has a very
>>broad range.
>
> Whether or not the test signal needs to be sinusoidal is irrelevant.
** Strange then how YOU raised the issue.
Go back and read the first para re the PRINCIPLE of operation.
> The fact is that it isn't. It is in fact an 8us 2kHz *pulse*.
** Which is AC coupled to the cap under test AND is a signal with energy
concentrated in the range above 100kHz.
> The
> principle of operation of the meter involves driving such a pulse into
> a pure C in series with a pure R. A discussion of a real capacitor's
> performance at 100kHz is just pointless obfuscation.
** You are DEAD WRONG !!
The PRINCIPLE of operation is that measuring an electo's IMPEDANCE at a
high frequency finds its ESR - because they are essentially the same number.
> All you need to know is that I = C * dV/dt. From this it follows that
> a constant current produces a voltage ramp.
** Completely irrelevant to has Bob's meter works.
The voltage across the cap under test is assumed to be entirely due to ESR -
and so it is for electos above a few uF.
> That's elementary circuit theory. Quite simple really.
** Piss off - dickhead.
>>> While the Xc of a 1uF cap at 100kHz
>>> is a negligible 1.6 ohms, that is not what the meter sees.
>>
>>
>> ** 1.6 ohms is very far from negligible for a film cap.
>
> Irrelevant. You were referring to electros.
** YOUR comment above refers to a film cap - dickhead.
> Anyway, nobody cares about
> the behaviour of the test cap at 100kHz.
** WRONG - that is how the ESR is being measured.
At that frequency, electro cap impedance and ESR are the same or similar.
>> It is, however, what the ESR meter reads with a 1uF film cap.
>
> The meter does not read Xc.
** WRONG - it reads Xc.
The PRINCIPLE of operation is that Xc = ESR over a range of high
frequencies.
> It reads *ESR*, or at least it thinks it does.
** Gobbledegook.
> In any case, the fact that the reading is "far from negligible"
> for a "pure" capacitance demonstrates that the meter has limitations,
> albeit acceptable ones, which was essentially the point of the OP's
> question.
** The OP never asked any such thing - dickhead.
>>> The test
>>> signal, at least for the Mark 2 version, is an 8us current pulse with
>>> a frequency of 2kHz.
>>
>>
>> ** It is an coupled AC signal, remember.
>
> Capacitors C5 and C6 have no effect since they are in series with a
> current source.
** The remove any DC component - you stubborn bloody ass.
The cap under tests cannot "charge up"
You are so UTTERLY wrong, Zabkar - there is no way to get anything RIGHT
into your fat head.
............ Phil
Phil Allison
"Franc Zabkar"
"Phil Allison"
>
> The OP wanted to know the range of an ESR meter.
** WRONG !!!!!!!!!!!!!!!!!!!!!
Here is the post:
" Anyone get Elektor Electronics magazine
http://213.222.12.205/Default.aspx?tabid=27&year=2005&month=9&art=52895&PN=O
Hopeless NZ bookshops have not put it on the shelf yet,
Does anyone know what capacitors range the ESR meter does? "
The new, Elektor meter is a COMBINED capacitance and ESR meter.
The OP was asking what range of capacitors it could test for capacitance.
Bob Parker's ESR meter has NOTHING to do with the OP's question !!!!!!!!!!
> I answered the
> question, both by actual testing, and by analysis of the design
> methodology.
** But for the WRONG meter and you got it all WRONG as well.
> The OP's question was in regard to the *limits* of measurement of the
> ESR meter.
** But NOT Bob Parker's one.
> In the absence of explicit specs from the manufacturer or
> designer, the answer to such a question requires an understanding of
> the measurement process ... or access to perfect caps. Therefore, the
> question of itself *demands* a pedantic answer.
** You are an autistic lunatic - piss off.
......... Phil
Phil Allison
"Franc Zabkar"
"Phil Allison"
>
> See this datasheet:
> http://www.vishay.com/docs/28119/mkp3382.pdf
** Please do - look at the impedance curves on page 7.
A 470nF cap has a resistance of **40 milliohms** at 2 MHz.
This represents the intrinsic, series resistance of the cap.
Bob Parker's ESR meter indicates the same parameter for an electro.
The big difference with electros is their impedance minimum is very broad -
ie the curve has a low Q.
......... Phil