Hi all,

Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
checks on large electros in the linear PSU I've previously mentioned
here. I was getting a lot of "in-circuit/leaky" warnings for two of
them, so I pulled them out completely and am getting the same warning
when they're checked out of circuit, which surprised me as it's
unusual IME. Anyway, the leak would have to be very bad to result in
ripple, would it not? AFAIK, the leading culprit for ripple is caps
which have lost a significant amount of capacitance or else developed
a very large ESR. Do I have that right?
I'd like a "second opinion" as it were on the leakiness of these caps.
What's the best old-school method for testing for this? I just want to
ensure the ESR meter isn't faulty (highly unlikely but the possibility
must be eliminated to be sure).

CD.

PS: the aforementioned caps are 47000uF 16V Vishay ones - and I have a
brand new spare that's also testing as "leaky"!

On Sun, 03 Mar 2024 18:03:51 +0000, Cursitor Doom <cd@notformail.com>
wrote:

>Hi all,
>
>Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>checks on large electros in the linear PSU I've previously mentioned
>here. I was getting a lot of "in-circuit/leaky" warnings for two of
>them, so I pulled them out completely and am getting the same warning
>when they're checked out of circuit, which surprised me as it's
>unusual IME. Anyway, the leak would have to be very bad to result in
>ripple, would it not? AFAIK, the leading culprit for ripple is caps
>which have lost a significant amount of capacitance or else developed
>a very large ESR. Do I have that right?
>I'd like a "second opinion" as it were on the leakiness of these caps.
>What's the best old-school method for testing for this? I just want to
>ensure the ESR meter isn't faulty (highly unlikely but the possibility
>must be eliminated to be sure).
>
>CD.
>
>PS: the aforementioned caps are 47000uF 16V Vishay ones - and I have a
>brand new spare that's also testing as "leaky"!

How leaky? You could apply 16 volts and measure current for a while.
It will typically taper off over some minutes or hours.

An electro that hasn't been used for some time will be leaky at first.
That's normal.

Expect a 47m cap to leak more than a 47u. Your capmeter may not know
the value.

It's interesting to test elec and polymer caps, current vs voltage
over time, forward and reverse.

On Sun, 03 Mar 2024 13:28:05 -0800, John Larkin <jl@997PotHill.com>
wrote:

>On Sun, 03 Mar 2024 18:03:51 +0000, Cursitor Doom <cd@notformail.com>
>wrote:
>
>>Hi all,
>>
>>Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>checks on large electros in the linear PSU I've previously mentioned
>>here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>them, so I pulled them out completely and am getting the same warning
>>when they're checked out of circuit, which surprised me as it's
>>unusual IME. Anyway, the leak would have to be very bad to result in
>>ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>which have lost a significant amount of capacitance or else developed
>>a very large ESR. Do I have that right?
>>I'd like a "second opinion" as it were on the leakiness of these caps.
>>What's the best old-school method for testing for this? I just want to
>>ensure the ESR meter isn't faulty (highly unlikely but the possibility
>>must be eliminated to be sure).
>>
>>CD.
>>
>>PS: the aforementioned caps are 47000uF 16V Vishay ones - and I have a
>>brand new spare that's also testing as "leaky"!
>
>How leaky? You could apply 16 volts and measure current for a while.
>It will typically taper off over some minutes or hours.

Well, the 'perfect cap' in series with an ammeter will cause an
initial surge of current which will taper off over time and eventually
settle at zero. But a leaky cap will continue to pass a small amount
of current, I would assume, indefinitely? Again, I would guess that a
real-world cap in good condition would continue to pass a tiny amount
of current - a negligible amount?

>An electro that hasn't been used for some time will be leaky at first.
>That's normal.

Good point.

>
>Expect a 47m cap to leak more than a 47u. Your capmeter may not know
>the value.

It wasn't able to measure the capacity at all. It did report a very
low ESR commensurate with a large value electrolytic. But that was all
it was able to measure.
>
>It's interesting to test elec and polymer caps, current vs voltage
>over time, forward and reverse.

Indeed.

On Sun, 03 Mar 2024 22:41:09 +0000, Cursitor Doom <cd@notformail.com>
wrote:

>On Sun, 03 Mar 2024 13:28:05 -0800, John Larkin <jl@997PotHill.com>
>wrote:
>
>>On Sun, 03 Mar 2024 18:03:51 +0000, Cursitor Doom <cd@notformail.com>
>>wrote:
>>
>>>Hi all,
>>>
>>>Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>>checks on large electros in the linear PSU I've previously mentioned
>>>here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>>them, so I pulled them out completely and am getting the same warning
>>>when they're checked out of circuit, which surprised me as it's
>>>unusual IME. Anyway, the leak would have to be very bad to result in
>>>ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>>which have lost a significant amount of capacitance or else developed
>>>a very large ESR. Do I have that right?
>>>I'd like a "second opinion" as it were on the leakiness of these caps.
>>>What's the best old-school method for testing for this? I just want to
>>>ensure the ESR meter isn't faulty (highly unlikely but the possibility
>>>must be eliminated to be sure).
>>>
>>>CD.
>>>
>>>PS: the aforementioned caps are 47000uF 16V Vishay ones - and I have a
>>>brand new spare that's also testing as "leaky"!
>>
>>How leaky? You could apply 16 volts and measure current for a while.
>>It will typically taper off over some minutes or hours.
>
>Well, the 'perfect cap' in series with an ammeter will cause an
>initial surge of current which will taper off over time and eventually
>settle at zero. But a leaky cap will continue to pass a small amount
>of current, I would assume, indefinitely? Again, I would guess that a
>real-world cap in good condition would continue to pass a tiny amount
>of current - a negligible amount?

An electrolytic is hardly a perfect cap. After the theoretical cap
charge, you might see some mA of leakage, tapering off to uA's after
some minutes or hours.

If the current ever increases, as it will at some voltage above rated,
it's probably on its way to destruction.

Get a power supply and an ammeter and experiment. Your capmeter is
obviously not telling you much.

On Sun, 03 Mar 2024 15:16:12 -0800, John Larkin <jl@997PotHill.com>
wrote:

>On Sun, 03 Mar 2024 22:41:09 +0000, Cursitor Doom <cd@notformail.com>
>wrote:
>
>>On Sun, 03 Mar 2024 13:28:05 -0800, John Larkin <jl@997PotHill.com>
>>wrote:
>>
>>>On Sun, 03 Mar 2024 18:03:51 +0000, Cursitor Doom <cd@notformail.com>
>>>wrote:
>>>
>>>>Hi all,
>>>>
>>>>Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>>>checks on large electros in the linear PSU I've previously mentioned
>>>>here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>>>them, so I pulled them out completely and am getting the same warning
>>>>when they're checked out of circuit, which surprised me as it's
>>>>unusual IME. Anyway, the leak would have to be very bad to result in
>>>>ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>>>which have lost a significant amount of capacitance or else developed
>>>>a very large ESR. Do I have that right?
>>>>I'd like a "second opinion" as it were on the leakiness of these caps.
>>>>What's the best old-school method for testing for this? I just want to
>>>>ensure the ESR meter isn't faulty (highly unlikely but the possibility
>>>>must be eliminated to be sure).
>>>>
>>>>CD.
>>>>
>>>>PS: the aforementioned caps are 47000uF 16V Vishay ones - and I have a
>>>>brand new spare that's also testing as "leaky"!
>>>
>>>How leaky? You could apply 16 volts and measure current for a while.
>>>It will typically taper off over some minutes or hours.
>>
>>Well, the 'perfect cap' in series with an ammeter will cause an
>>initial surge of current which will taper off over time and eventually
>>settle at zero. But a leaky cap will continue to pass a small amount
>>of current, I would assume, indefinitely? Again, I would guess that a
>>real-world cap in good condition would continue to pass a tiny amount
>>of current - a negligible amount?
>
>An electrolytic is hardly a perfect cap. After the theoretical cap
>charge, you might see some mA of leakage, tapering off to uA's after
>some minutes or hours.
>
>If the current ever increases, as it will at some voltage above rated,
>it's probably on its way to destruction.
>
>Get a power supply and an ammeter and experiment. Your capmeter is
>obviously not telling you much.
>

Just spotted the meter only covers up to 22,000uF!
we

On Sun, 03 Mar 2024 23:50:08 +0000, Cursitor Doom <cd@notformail.com>
wrote:

>On Sun, 03 Mar 2024 15:16:12 -0800, John Larkin <jl@997PotHill.com>
>wrote:
>
>>On Sun, 03 Mar 2024 22:41:09 +0000, Cursitor Doom <cd@notformail.com>
>>wrote:
>>
>>>On Sun, 03 Mar 2024 13:28:05 -0800, John Larkin <jl@997PotHill.com>
>>>wrote:
>>>
>>>>On Sun, 03 Mar 2024 18:03:51 +0000, Cursitor Doom <cd@notformail.com>
>>>>wrote:
>>>>
>>>>>Hi all,
>>>>>
>>>>>Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>>>>checks on large electros in the linear PSU I've previously mentioned
>>>>>here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>>>>them, so I pulled them out completely and am getting the same warning
>>>>>when they're checked out of circuit, which surprised me as it's
>>>>>unusual IME. Anyway, the leak would have to be very bad to result in
>>>>>ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>>>>which have lost a significant amount of capacitance or else developed
>>>>>a very large ESR. Do I have that right?
>>>>>I'd like a "second opinion" as it were on the leakiness of these caps.
>>>>>What's the best old-school method for testing for this? I just want to
>>>>>ensure the ESR meter isn't faulty (highly unlikely but the possibility
>>>>>must be eliminated to be sure).
>>>>>
>>>>>CD.
>>>>>
>>>>>PS: the aforementioned caps are 47000uF 16V Vishay ones - and I have a
>>>>>brand new spare that's also testing as "leaky"!
>>>>
>>>>How leaky? You could apply 16 volts and measure current for a while.
>>>>It will typically taper off over some minutes or hours.
>>>
>>>Well, the 'perfect cap' in series with an ammeter will cause an
>>>initial surge of current which will taper off over time and eventually
>>>settle at zero. But a leaky cap will continue to pass a small amount
>>>of current, I would assume, indefinitely? Again, I would guess that a
>>>real-world cap in good condition would continue to pass a tiny amount
>>>of current - a negligible amount?
>>
>>An electrolytic is hardly a perfect cap. After the theoretical cap
>>charge, you might see some mA of leakage, tapering off to uA's after
>>some minutes or hours.
>>
>>If the current ever increases, as it will at some voltage above rated,
>>it's probably on its way to destruction.
>>
>>Get a power supply and an ammeter and experiment. Your capmeter is
>>obviously not telling you much.
>>
>
>
>Just spotted the meter only covers up to 22,000uF!
>we

I don't trust C or L meters, especially for large C or L values, or
cheap meters.

On Sun, 03 Mar 2024 16:22:12 -0800, John Larkin <jl@997PotHill.com>
wrote:

>On Sun, 03 Mar 2024 23:50:08 +0000, Cursitor Doom <cd@notformail.com>
>wrote:
>
>>On Sun, 03 Mar 2024 15:16:12 -0800, John Larkin <jl@997PotHill.com>
>>wrote:
>>
>>>On Sun, 03 Mar 2024 22:41:09 +0000, Cursitor Doom <cd@notformail.com>
>>>wrote:
>>>
>>>>On Sun, 03 Mar 2024 13:28:05 -0800, John Larkin <jl@997PotHill.com>
>>>>wrote:
>>>>
>>>>>On Sun, 03 Mar 2024 18:03:51 +0000, Cursitor Doom <cd@notformail.com>
>>>>>wrote:
>>>>>
>>>>>>Hi all,
>>>>>>
>>>>>>Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>>>>>checks on large electros in the linear PSU I've previously mentioned
>>>>>>here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>>>>>them, so I pulled them out completely and am getting the same warning
>>>>>>when they're checked out of circuit, which surprised me as it's
>>>>>>unusual IME. Anyway, the leak would have to be very bad to result in
>>>>>>ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>>>>>which have lost a significant amount of capacitance or else developed
>>>>>>a very large ESR. Do I have that right?
>>>>>>I'd like a "second opinion" as it were on the leakiness of these caps.
>>>>>>What's the best old-school method for testing for this? I just want to
>>>>>>ensure the ESR meter isn't faulty (highly unlikely but the possibility
>>>>>>must be eliminated to be sure).
>>>>>>
>>>>>>CD.
>>>>>>
>>>>>>PS: the aforementioned caps are 47000uF 16V Vishay ones - and I have a
>>>>>>brand new spare that's also testing as "leaky"!
>>>>>
>>>>>How leaky? You could apply 16 volts and measure current for a while.
>>>>>It will typically taper off over some minutes or hours.
>>>>
>>>>Well, the 'perfect cap' in series with an ammeter will cause an
>>>>initial surge of current which will taper off over time and eventually
>>>>settle at zero. But a leaky cap will continue to pass a small amount
>>>>of current, I would assume, indefinitely? Again, I would guess that a
>>>>real-world cap in good condition would continue to pass a tiny amount
>>>>of current - a negligible amount?
>>>
>>>An electrolytic is hardly a perfect cap. After the theoretical cap
>>>charge, you might see some mA of leakage, tapering off to uA's after
>>>some minutes or hours.
>>>
>>>If the current ever increases, as it will at some voltage above rated,
>>>it's probably on its way to destruction.
>>>
>>>Get a power supply and an ammeter and experiment. Your capmeter is
>>>obviously not telling you much.
>>>
>>
>>
>>Just spotted the meter only covers up to 22,000uF!
>>we
>
>I don't trust C or L meters, especially for large C or L values, or
>cheap meters.

How would you test for leakage, then? Those Peak meters aren't cheap
and they've never let me down before. I suppose technically this one
hasn't let me down either since I was attempting an out-of-range
measurement. Perhaps the later models have expanded ranges; I'll have
to check....

On Mon, 04 Mar 2024 00:31:27 +0000, Cursitor Doom <cd@notformail.com>
wrote:

>On Sun, 03 Mar 2024 16:22:12 -0800, John Larkin <jl@997PotHill.com>
>wrote:
>
>>On Sun, 03 Mar 2024 23:50:08 +0000, Cursitor Doom <cd@notformail.com>
>>wrote:
>>
>>>On Sun, 03 Mar 2024 15:16:12 -0800, John Larkin <jl@997PotHill.com>
>>>wrote:
>>>
>>>>On Sun, 03 Mar 2024 22:41:09 +0000, Cursitor Doom <cd@notformail.com>
>>>>wrote:
>>>>
>>>>>On Sun, 03 Mar 2024 13:28:05 -0800, John Larkin <jl@997PotHill.com>
>>>>>wrote:
>>>>>
>>>>>>On Sun, 03 Mar 2024 18:03:51 +0000, Cursitor Doom <cd@notformail.com>
>>>>>>wrote:
>>>>>>
>>>>>>>Hi all,
>>>>>>>
>>>>>>>Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>>>>>>checks on large electros in the linear PSU I've previously mentioned
>>>>>>>here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>>>>>>them, so I pulled them out completely and am getting the same warning
>>>>>>>when they're checked out of circuit, which surprised me as it's
>>>>>>>unusual IME. Anyway, the leak would have to be very bad to result in
>>>>>>>ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>>>>>>which have lost a significant amount of capacitance or else developed
>>>>>>>a very large ESR. Do I have that right?
>>>>>>>I'd like a "second opinion" as it were on the leakiness of these caps.
>>>>>>>What's the best old-school method for testing for this? I just want to
>>>>>>>ensure the ESR meter isn't faulty (highly unlikely but the possibility
>>>>>>>must be eliminated to be sure).
>>>>>>>
>>>>>>>CD.
>>>>>>>
>>>>>>>PS: the aforementioned caps are 47000uF 16V Vishay ones - and I have a
>>>>>>>brand new spare that's also testing as "leaky"!
>>>>>>
>>>>>>How leaky? You could apply 16 volts and measure current for a while.
>>>>>>It will typically taper off over some minutes or hours.
>>>>>
>>>>>Well, the 'perfect cap' in series with an ammeter will cause an
>>>>>initial surge of current which will taper off over time and eventually
>>>>>settle at zero. But a leaky cap will continue to pass a small amount
>>>>>of current, I would assume, indefinitely? Again, I would guess that a
>>>>>real-world cap in good condition would continue to pass a tiny amount
>>>>>of current - a negligible amount?
>>>>
>>>>An electrolytic is hardly a perfect cap. After the theoretical cap
>>>>charge, you might see some mA of leakage, tapering off to uA's after
>>>>some minutes or hours.
>>>>
>>>>If the current ever increases, as it will at some voltage above rated,
>>>>it's probably on its way to destruction.
>>>>
>>>>Get a power supply and an ammeter and experiment. Your capmeter is
>>>>obviously not telling you much.
>>>>
>>>
>>>
>>>Just spotted the meter only covers up to 22,000uF!
>>>we
>>
>>I don't trust C or L meters, especially for large C or L values, or
>>cheap meters.
>
>How would you test for leakage, then?

Power supply and DVM.

>Those Peak meters aren't cheap
>and they've never let me down before. I suppose technically this one
>hasn't let me down either since I was attempting an out-of-range
>measurement. Perhaps the later models have expanded ranges; I'll have
>to check....

In article <1u4auilip8353mc4d2283npupk14871cen@4ax.com>, jl@
997PotHill.com says...
>
> I don't trust C or L meters, especially for large C or L values, or
> cheap meters.
>
>
>

The better capacitor testers will test the capacitor under its rated
voltage, especially the electrolytics.

If they have not been used is a long time it takes the rated voltage for
them to reform. The factory usually forms them at a higher voltage than
they are rated for.

In article <td5aui1cdl3k1oeogl085e5lvc2p10o5ke@4ax.com>,
cd@notformail.com says...
>
> How would you test for leakage, then? Those Peak meters aren't cheap
> and they've never let me down before. I suppose technically this one
> hasn't let me down either since I was attempting an out-of-range
> measurement. Perhaps the later models have expanded ranges; I'll have
> to check....
>
>
>

The Peak metrs are only expensive because of the name. China has the
same thing on ebay for around $ 20. The China ones have multifunctions
instead of just one or two the Peak meters have. That is so Peak can
sell you two or three meters that are really the same but functions
missing.

On 4/03/2024 5:03 am, Cursitor Doom wrote:
> Hi all,
>
> Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
> checks on large electros in the linear PSU I've previously mentioned
> here. I was getting a lot of "in-circuit/leaky" warnings for two of
> them, so I pulled them out completely and am getting the same warning
> when they're checked out of circuit, which surprised me as it's
> unusual IME. Anyway, the leak would have to be very bad to result in
> ripple, would it not? AFAIK, the leading culprit for ripple is caps
> which have lost a significant amount of capacitance or else developed
> a very large ESR. Do I have that right?

What you have wrong is the imagined association between leakage and ripple.

The "ripple" on the voltage across a capacitor reflects the charge that
is being taken out of and fed into the capacitor over the mains cycle.
More capacitance means smaller ripple.

Leakage is just the current flowing through the oxide layer on top of
metal conductor surfaces inside the electrolytic capacitor. If the
capacitor has been un-used for a long time, some of the oxide layer may
have diffused away, making the capacitance and the leakage current
higher. Applying the working voltage will re-form the oxide layer by
making it a bit thicker.

> I'd like a "second opinion" as it were on the leakiness of these caps.
> What's the best old-school method for testing for this? I just want to
> ensure the ESR meter isn't faulty (highly unlikely but the possibility
> must be eliminated to be sure).

If an electrolytic capacitor hasn't been used for some time, it's going
to be leaky. If you want to measure how leaky, measure the direct
current flowing through the capacitor as you increase the bias voltage
across it. It should drop as the oxide layer re-forms, perhaps over hours.

--
Bill Sloman, Sydney

On Mon, 4 Mar 2024 15:29:02 +1100, Bill Sloman <bill.sloman@ieee.org>
wrote:

>On 4/03/2024 5:03 am, Cursitor Doom wrote:
>> Hi all,
>>
>> Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>> checks on large electros in the linear PSU I've previously mentioned
>> here. I was getting a lot of "in-circuit/leaky" warnings for two of
>> them, so I pulled them out completely and am getting the same warning
>> when they're checked out of circuit, which surprised me as it's
>> unusual IME. Anyway, the leak would have to be very bad to result in
>> ripple, would it not? AFAIK, the leading culprit for ripple is caps
>> which have lost a significant amount of capacitance or else developed
>> a very large ESR. Do I have that right?
>
>What you have wrong is the imagined association between leakage and ripple.

Eh? I did say leakage was probably about the least likely cause of
ripple!

>
>The "ripple" on the voltage across a capacitor reflects the charge that
>is being taken out of and fed into the capacitor over the mains cycle.
>More capacitance means smaller ripple.
>
>Leakage is just the current flowing through the oxide layer on top of
>metal conductor surfaces inside the electrolytic capacitor. If the
>capacitor has been un-used for a long time, some of the oxide layer may
>have diffused away, making the capacitance and the leakage current
>higher. Applying the working voltage will re-form the oxide layer by
>making it a bit thicker.
>
>> I'd like a "second opinion" as it were on the leakiness of these caps.
>> What's the best old-school method for testing for this? I just want to
>> ensure the ESR meter isn't faulty (highly unlikely but the possibility
>> must be eliminated to be sure).
>
>If an electrolytic capacitor hasn't been used for some time, it's going
>to be leaky. If you want to measure how leaky, measure the direct
>current flowing through the capacitor as you increase the bias voltage
>across it. It should drop as the oxide layer re-forms, perhaps over hours.

On Sun, 03 Mar 2024 18:28:46 -0800, John Larkin <jl@997PotHill.com>
wrote:

>On Mon, 04 Mar 2024 00:31:27 +0000, Cursitor Doom <cd@notformail.com>
>wrote:
>
>>On Sun, 03 Mar 2024 16:22:12 -0800, John Larkin <jl@997PotHill.com>
>>wrote:
>>
>>>On Sun, 03 Mar 2024 23:50:08 +0000, Cursitor Doom <cd@notformail.com>
>>>wrote:
>>>
>>>>On Sun, 03 Mar 2024 15:16:12 -0800, John Larkin <jl@997PotHill.com>
>>>>wrote:
>>>>
>>>>>On Sun, 03 Mar 2024 22:41:09 +0000, Cursitor Doom <cd@notformail.com>
>>>>>wrote:
>>>>>
>>>>>>On Sun, 03 Mar 2024 13:28:05 -0800, John Larkin <jl@997PotHill.com>
>>>>>>wrote:
>>>>>>
>>>>>>>On Sun, 03 Mar 2024 18:03:51 +0000, Cursitor Doom <cd@notformail.com>
>>>>>>>wrote:
>>>>>>>
>>>>>>>>Hi all,
>>>>>>>>
>>>>>>>>Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>>>>>>>checks on large electros in the linear PSU I've previously mentioned
>>>>>>>>here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>>>>>>>them, so I pulled them out completely and am getting the same warning
>>>>>>>>when they're checked out of circuit, which surprised me as it's
>>>>>>>>unusual IME. Anyway, the leak would have to be very bad to result in
>>>>>>>>ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>>>>>>>which have lost a significant amount of capacitance or else developed
>>>>>>>>a very large ESR. Do I have that right?
>>>>>>>>I'd like a "second opinion" as it were on the leakiness of these caps.
>>>>>>>>What's the best old-school method for testing for this? I just want to
>>>>>>>>ensure the ESR meter isn't faulty (highly unlikely but the possibility
>>>>>>>>must be eliminated to be sure).
>>>>>>>>
>>>>>>>>CD.
>>>>>>>>
>>>>>>>>PS: the aforementioned caps are 47000uF 16V Vishay ones - and I have a
>>>>>>>>brand new spare that's also testing as "leaky"!
>>>>>>>
>>>>>>>How leaky? You could apply 16 volts and measure current for a while.
>>>>>>>It will typically taper off over some minutes or hours.
>>>>>>
>>>>>>Well, the 'perfect cap' in series with an ammeter will cause an
>>>>>>initial surge of current which will taper off over time and eventually
>>>>>>settle at zero. But a leaky cap will continue to pass a small amount
>>>>>>of current, I would assume, indefinitely? Again, I would guess that a
>>>>>>real-world cap in good condition would continue to pass a tiny amount
>>>>>>of current - a negligible amount?
>>>>>
>>>>>An electrolytic is hardly a perfect cap. After the theoretical cap
>>>>>charge, you might see some mA of leakage, tapering off to uA's after
>>>>>some minutes or hours.
>>>>>
>>>>>If the current ever increases, as it will at some voltage above rated,
>>>>>it's probably on its way to destruction.
>>>>>
>>>>>Get a power supply and an ammeter and experiment. Your capmeter is
>>>>>obviously not telling you much.
>>>>>
>>>>
>>>>
>>>>Just spotted the meter only covers up to 22,000uF!
>>>>we
>>>
>>>I don't trust C or L meters, especially for large C or L values, or
>>>cheap meters.
>>
>>How would you test for leakage, then?
>
>Power supply and DVM.

But then how do you determine - given that electrolytics come in all
sorts of votlage and temperature ratings, capacitance values etc - how
much leakage current in each case is "too much" leakage current
rendering the cap unsuitable for use?

>
>>Those Peak meters aren't cheap
>>and they've never let me down before. I suppose technically this one
>>hasn't let me down either since I was attempting an out-of-range
>>measurement. Perhaps the later models have expanded ranges; I'll have
>>to check....

On Mon, 04 Mar 2024 15:55:53 +0000, Cursitor Doom <cd@notformail.com>
wrote:

>On Sun, 03 Mar 2024 18:28:46 -0800, John Larkin <jl@997PotHill.com>
>wrote:
>
>>On Mon, 04 Mar 2024 00:31:27 +0000, Cursitor Doom <cd@notformail.com>
>>wrote:
>>
>>>On Sun, 03 Mar 2024 16:22:12 -0800, John Larkin <jl@997PotHill.com>
>>>wrote:
>>>
>>>>On Sun, 03 Mar 2024 23:50:08 +0000, Cursitor Doom <cd@notformail.com>
>>>>wrote:
>>>>
>>>>>On Sun, 03 Mar 2024 15:16:12 -0800, John Larkin <jl@997PotHill.com>
>>>>>wrote:
>>>>>
>>>>>>On Sun, 03 Mar 2024 22:41:09 +0000, Cursitor Doom <cd@notformail.com>
>>>>>>wrote:
>>>>>>
>>>>>>>On Sun, 03 Mar 2024 13:28:05 -0800, John Larkin <jl@997PotHill.com>
>>>>>>>wrote:
>>>>>>>
>>>>>>>>On Sun, 03 Mar 2024 18:03:51 +0000, Cursitor Doom <cd@notformail.com>
>>>>>>>>wrote:
>>>>>>>>
>>>>>>>>>Hi all,
>>>>>>>>>
>>>>>>>>>Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>>>>>>>>checks on large electros in the linear PSU I've previously mentioned
>>>>>>>>>here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>>>>>>>>them, so I pulled them out completely and am getting the same warning
>>>>>>>>>when they're checked out of circuit, which surprised me as it's
>>>>>>>>>unusual IME. Anyway, the leak would have to be very bad to result in
>>>>>>>>>ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>>>>>>>>which have lost a significant amount of capacitance or else developed
>>>>>>>>>a very large ESR. Do I have that right?
>>>>>>>>>I'd like a "second opinion" as it were on the leakiness of these caps.
>>>>>>>>>What's the best old-school method for testing for this? I just want to
>>>>>>>>>ensure the ESR meter isn't faulty (highly unlikely but the possibility
>>>>>>>>>must be eliminated to be sure).
>>>>>>>>>
>>>>>>>>>CD.
>>>>>>>>>
>>>>>>>>>PS: the aforementioned caps are 47000uF 16V Vishay ones - and I have a
>>>>>>>>>brand new spare that's also testing as "leaky"!
>>>>>>>>
>>>>>>>>How leaky? You could apply 16 volts and measure current for a while.
>>>>>>>>It will typically taper off over some minutes or hours.
>>>>>>>
>>>>>>>Well, the 'perfect cap' in series with an ammeter will cause an
>>>>>>>initial surge of current which will taper off over time and eventually
>>>>>>>settle at zero. But a leaky cap will continue to pass a small amount
>>>>>>>of current, I would assume, indefinitely? Again, I would guess that a
>>>>>>>real-world cap in good condition would continue to pass a tiny amount
>>>>>>>of current - a negligible amount?
>>>>>>
>>>>>>An electrolytic is hardly a perfect cap. After the theoretical cap
>>>>>>charge, you might see some mA of leakage, tapering off to uA's after
>>>>>>some minutes or hours.
>>>>>>
>>>>>>If the current ever increases, as it will at some voltage above rated,
>>>>>>it's probably on its way to destruction.
>>>>>>
>>>>>>Get a power supply and an ammeter and experiment. Your capmeter is
>>>>>>obviously not telling you much.
>>>>>>
>>>>>
>>>>>
>>>>>Just spotted the meter only covers up to 22,000uF!
>>>>>we
>>>>
>>>>I don't trust C or L meters, especially for large C or L values, or
>>>>cheap meters.
>>>
>>>How would you test for leakage, then?
>>
>>Power supply and DVM.
>
>But then how do you determine - given that electrolytics come in all
>sorts of votlage and temperature ratings, capacitance values etc - how
>much leakage current in each case is "too much" leakage current
>rendering the cap unsuitable for use?

That's for you to decide. No instrument is going to have red and green
LEDs to tell you if a cap is suitable for your circuit.

You might care about

Gross capacitance
C vs voltage
C vs temperature
Leakage vs temperature and voltage, both polarities
Dielectric absorption
Failure voltage or current
ESR vs temperature
ESL
Lifetime
Power dissipation/cooling
Solderability/washability

One should measure or calculate whichever of those might matter in
your circuit.

Post your circuit and we can talk about it.

>
>>
>>>Those Peak meters aren't cheap
>>>and they've never let me down before. I suppose technically this one
>>>hasn't let me down either since I was attempting an out-of-range
>>>measurement. Perhaps the later models have expanded ranges; I'll have
>>>to check....

On Mon, 04 Mar 2024 15:50:21 +0000, Cursitor Doom <cd@notformail.com>
wrote:

>On Mon, 4 Mar 2024 15:29:02 +1100, Bill Sloman <bill.sloman@ieee.org>
>wrote:
>
>>On 4/03/2024 5:03 am, Cursitor Doom wrote:
>>> Hi all,
>>>
>>> Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>> checks on large electros in the linear PSU I've previously mentioned
>>> here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>> them, so I pulled them out completely and am getting the same warning
>>> when they're checked out of circuit, which surprised me as it's
>>> unusual IME. Anyway, the leak would have to be very bad to result in
>>> ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>> which have lost a significant amount of capacitance or else developed
>>> a very large ESR. Do I have that right?
>>
>>What you have wrong is the imagined association between leakage and ripple.
>
>Eh? I did say leakage was probably about the least likely cause of
>ripple!

Don't argue. Sloman is always right and everyone else is always wrong
and stupid.

On Mon, 04 Mar 2024 09:20:12 -0800, John Larkin <jl@997PotHill.com>
wrote:

>On Mon, 04 Mar 2024 15:50:21 +0000, Cursitor Doom <cd@notformail.com>
>wrote:
>
>>On Mon, 4 Mar 2024 15:29:02 +1100, Bill Sloman <bill.sloman@ieee.org>
>>wrote:
>>
>>>On 4/03/2024 5:03 am, Cursitor Doom wrote:
>>>> Hi all,
>>>>
>>>> Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>>> checks on large electros in the linear PSU I've previously mentioned
>>>> here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>>> them, so I pulled them out completely and am getting the same warning
>>>> when they're checked out of circuit, which surprised me as it's
>>>> unusual IME. Anyway, the leak would have to be very bad to result in
>>>> ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>>> which have lost a significant amount of capacitance or else developed
>>>> a very large ESR. Do I have that right?
>>>
>>>What you have wrong is the imagined association between leakage and ripple.
>>
>>Eh? I did say leakage was probably about the least likely cause of
>>ripple!
>
>Don't argue. Sloman is always right and everyone else is always wrong
>and stupid.

Much of that can be accounted for by the fact that Bill doesn't bother
reading others' comments in their entirety. He goes off 'half-cock'
and makes an ass of himself. That doesn't say much for his claims to
be a scientist.

On Mon, 4 Mar 2024 17:00:26 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

>Cursitor Doom <cd@notformail.com> wrote:
>
>[...]
>> But then how do you determine - given that electrolytics come in all
>> sorts of votlage and temperature ratings, capacitance values etc - how
>> much leakage current in each case is "too much" leakage current
>> rendering the cap unsuitable for use?
>
>According to the Post Office Elelctrical Engineers' Journal (July 1962
>p120) the leakage should be less than 5,000 ohm-farads for electrolytic
>capacitors to be accepted for use in undersea cable repeaters. If your
>capacitor is 47,000 microfarads (0.047F), that leakage current would be
>equivalent to about 100k i.e. 0.1 milliamps at 10v.
>
>For general domestic use, leakage figures at least 10 times greater than
>that are usually acceptable.

Seems pretty definitive. Thanks, Liz.

On Mon, 04 Mar 2024 09:16:53 -0800, John Larkin <jl@997PotHill.com>
wrote:

>On Mon, 04 Mar 2024 15:55:53 +0000, Cursitor Doom <cd@notformail.com>
>wrote:
>
>>On Sun, 03 Mar 2024 18:28:46 -0800, John Larkin <jl@997PotHill.com>
>>wrote:
>>
>>>On Mon, 04 Mar 2024 00:31:27 +0000, Cursitor Doom <cd@notformail.com>
>>>wrote:
>>>
>>>>On Sun, 03 Mar 2024 16:22:12 -0800, John Larkin <jl@997PotHill.com>
>>>>wrote:
>>>>
>>>>>On Sun, 03 Mar 2024 23:50:08 +0000, Cursitor Doom <cd@notformail.com>
>>>>>wrote:
>>>>>
>>>>>>On Sun, 03 Mar 2024 15:16:12 -0800, John Larkin <jl@997PotHill.com>
>>>>>>wrote:
>>>>>>
>>>>>>>On Sun, 03 Mar 2024 22:41:09 +0000, Cursitor Doom <cd@notformail.com>
>>>>>>>wrote:
>>>>>>>
>>>>>>>>On Sun, 03 Mar 2024 13:28:05 -0800, John Larkin <jl@997PotHill.com>
>>>>>>>>wrote:
>>>>>>>>
>>>>>>>>>On Sun, 03 Mar 2024 18:03:51 +0000, Cursitor Doom <cd@notformail.com>
>>>>>>>>>wrote:
>>>>>>>>>
>>>>>>>>>>Hi all,
>>>>>>>>>>
>>>>>>>>>>Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>>>>>>>>>checks on large electros in the linear PSU I've previously mentioned
>>>>>>>>>>here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>>>>>>>>>them, so I pulled them out completely and am getting the same warning
>>>>>>>>>>when they're checked out of circuit, which surprised me as it's
>>>>>>>>>>unusual IME. Anyway, the leak would have to be very bad to result in
>>>>>>>>>>ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>>>>>>>>>which have lost a significant amount of capacitance or else developed
>>>>>>>>>>a very large ESR. Do I have that right?
>>>>>>>>>>I'd like a "second opinion" as it were on the leakiness of these caps.
>>>>>>>>>>What's the best old-school method for testing for this? I just want to
>>>>>>>>>>ensure the ESR meter isn't faulty (highly unlikely but the possibility
>>>>>>>>>>must be eliminated to be sure).
>>>>>>>>>>
>>>>>>>>>>CD.
>>>>>>>>>>
>>>>>>>>>>PS: the aforementioned caps are 47000uF 16V Vishay ones - and I have a
>>>>>>>>>>brand new spare that's also testing as "leaky"!
>>>>>>>>>
>>>>>>>>>How leaky? You could apply 16 volts and measure current for a while.
>>>>>>>>>It will typically taper off over some minutes or hours.
>>>>>>>>
>>>>>>>>Well, the 'perfect cap' in series with an ammeter will cause an
>>>>>>>>initial surge of current which will taper off over time and eventually
>>>>>>>>settle at zero. But a leaky cap will continue to pass a small amount
>>>>>>>>of current, I would assume, indefinitely? Again, I would guess that a
>>>>>>>>real-world cap in good condition would continue to pass a tiny amount
>>>>>>>>of current - a negligible amount?
>>>>>>>
>>>>>>>An electrolytic is hardly a perfect cap. After the theoretical cap
>>>>>>>charge, you might see some mA of leakage, tapering off to uA's after
>>>>>>>some minutes or hours.
>>>>>>>
>>>>>>>If the current ever increases, as it will at some voltage above rated,
>>>>>>>it's probably on its way to destruction.
>>>>>>>
>>>>>>>Get a power supply and an ammeter and experiment. Your capmeter is
>>>>>>>obviously not telling you much.
>>>>>>>
>>>>>>
>>>>>>
>>>>>>Just spotted the meter only covers up to 22,000uF!
>>>>>>we
>>>>>
>>>>>I don't trust C or L meters, especially for large C or L values, or
>>>>>cheap meters.
>>>>
>>>>How would you test for leakage, then?
>>>
>>>Power supply and DVM.
>>
>>But then how do you determine - given that electrolytics come in all
>>sorts of votlage and temperature ratings, capacitance values etc - how
>>much leakage current in each case is "too much" leakage current
>>rendering the cap unsuitable for use?
>
>That's for you to decide. No instrument is going to have red and green
>LEDs to tell you if a cap is suitable for your circuit.

That's not how cap testers work, though. They take virtually none of
the following into account:-

>Gross capacitance
>C vs voltage
>C vs temperature
>Leakage vs temperature and voltage, both polarities
>Dielectric absorption
>Failure voltage or current
>ESR vs temperature
>ESL
>Lifetime
>Power dissipation/cooling
>Solderability/washability
>
>One should measure or calculate whichever of those might matter in
>your circuit.
>
>Post your circuit and we can talk about it.

No circuit involved. The question relates to generic smoothing caps of
linear power supplies.

On Mon, 04 Mar 2024 23:03:05 +0000, Cursitor Doom <cd@notformail.com>
wrote:

>On Mon, 04 Mar 2024 09:16:53 -0800, John Larkin <jl@997PotHill.com>
>wrote:
>
>>On Mon, 04 Mar 2024 15:55:53 +0000, Cursitor Doom <cd@notformail.com>
>>wrote:
>>
>>>On Sun, 03 Mar 2024 18:28:46 -0800, John Larkin <jl@997PotHill.com>
>>>wrote:
>>>
>>>>On Mon, 04 Mar 2024 00:31:27 +0000, Cursitor Doom <cd@notformail.com>
>>>>wrote:
>>>>
>>>>>On Sun, 03 Mar 2024 16:22:12 -0800, John Larkin <jl@997PotHill.com>
>>>>>wrote:
>>>>>
>>>>>>On Sun, 03 Mar 2024 23:50:08 +0000, Cursitor Doom <cd@notformail.com>
>>>>>>wrote:
>>>>>>
>>>>>>>On Sun, 03 Mar 2024 15:16:12 -0800, John Larkin <jl@997PotHill.com>
>>>>>>>wrote:
>>>>>>>
>>>>>>>>On Sun, 03 Mar 2024 22:41:09 +0000, Cursitor Doom <cd@notformail.com>
>>>>>>>>wrote:
>>>>>>>>
>>>>>>>>>On Sun, 03 Mar 2024 13:28:05 -0800, John Larkin <jl@997PotHill.com>
>>>>>>>>>wrote:
>>>>>>>>>
>>>>>>>>>>On Sun, 03 Mar 2024 18:03:51 +0000, Cursitor Doom <cd@notformail.com>
>>>>>>>>>>wrote:
>>>>>>>>>>
>>>>>>>>>>>Hi all,
>>>>>>>>>>>
>>>>>>>>>>>Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>>>>>>>>>>checks on large electros in the linear PSU I've previously mentioned
>>>>>>>>>>>here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>>>>>>>>>>them, so I pulled them out completely and am getting the same warning
>>>>>>>>>>>when they're checked out of circuit, which surprised me as it's
>>>>>>>>>>>unusual IME. Anyway, the leak would have to be very bad to result in
>>>>>>>>>>>ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>>>>>>>>>>which have lost a significant amount of capacitance or else developed
>>>>>>>>>>>a very large ESR. Do I have that right?
>>>>>>>>>>>I'd like a "second opinion" as it were on the leakiness of these caps.
>>>>>>>>>>>What's the best old-school method for testing for this? I just want to
>>>>>>>>>>>ensure the ESR meter isn't faulty (highly unlikely but the possibility
>>>>>>>>>>>must be eliminated to be sure).
>>>>>>>>>>>
>>>>>>>>>>>CD.
>>>>>>>>>>>
>>>>>>>>>>>PS: the aforementioned caps are 47000uF 16V Vishay ones - and I have a
>>>>>>>>>>>brand new spare that's also testing as "leaky"!
>>>>>>>>>>
>>>>>>>>>>How leaky? You could apply 16 volts and measure current for a while.
>>>>>>>>>>It will typically taper off over some minutes or hours.
>>>>>>>>>
>>>>>>>>>Well, the 'perfect cap' in series with an ammeter will cause an
>>>>>>>>>initial surge of current which will taper off over time and eventually
>>>>>>>>>settle at zero. But a leaky cap will continue to pass a small amount
>>>>>>>>>of current, I would assume, indefinitely? Again, I would guess that a
>>>>>>>>>real-world cap in good condition would continue to pass a tiny amount
>>>>>>>>>of current - a negligible amount?
>>>>>>>>
>>>>>>>>An electrolytic is hardly a perfect cap. After the theoretical cap
>>>>>>>>charge, you might see some mA of leakage, tapering off to uA's after
>>>>>>>>some minutes or hours.
>>>>>>>>
>>>>>>>>If the current ever increases, as it will at some voltage above rated,
>>>>>>>>it's probably on its way to destruction.
>>>>>>>>
>>>>>>>>Get a power supply and an ammeter and experiment. Your capmeter is
>>>>>>>>obviously not telling you much.
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>Just spotted the meter only covers up to 22,000uF!
>>>>>>>we
>>>>>>
>>>>>>I don't trust C or L meters, especially for large C or L values, or
>>>>>>cheap meters.
>>>>>
>>>>>How would you test for leakage, then?
>>>>
>>>>Power supply and DVM.
>>>
>>>But then how do you determine - given that electrolytics come in all
>>>sorts of votlage and temperature ratings, capacitance values etc - how
>>>much leakage current in each case is "too much" leakage current
>>>rendering the cap unsuitable for use?
>>
>>That's for you to decide. No instrument is going to have red and green
>>LEDs to tell you if a cap is suitable for your circuit.
>
>That's not how cap testers work, though. They take virtually none of
>the following into account:-
>
>>Gross capacitance
>>C vs voltage
>>C vs temperature
>>Leakage vs temperature and voltage, both polarities
>>Dielectric absorption
>>Failure voltage or current
>>ESR vs temperature
>>ESL
>>Lifetime
>>Power dissipation/cooling
>>Solderability/washability
>>
>>One should measure or calculate whichever of those might matter in
>>your circuit.
>>
>>Post your circuit and we can talk about it.
>
>No circuit involved. The question relates to generic smoothing caps of
>linear power supplies.

Where in a circuit is a "smoothing" cap? Oops, sorry, there is no
circuit.

On 5/03/2024 2:50 am, Cursitor Doom wrote:
> On Mon, 4 Mar 2024 15:29:02 +1100, Bill Sloman <bill.sloman@ieee.org>
> wrote:
>
>> On 4/03/2024 5:03 am, Cursitor Doom wrote:
>>> Hi all,
>>>
>>> Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>> checks on large electros in the linear PSU I've previously mentioned
>>> here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>> them, so I pulled them out completely and am getting the same warning
>>> when they're checked out of circuit, which surprised me as it's
>>> unusual IME. Anyway, the leak would have to be very bad to result in
>>> ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>> which have lost a significant amount of capacitance or else developed
>>> a very large ESR. Do I have that right?
>>
>> What you have wrong is the imagined association between leakage and ripple.
>
> Eh? I did say leakage was probably about the least likely cause of
> ripple!

The error comes from imagining that the two were connected.

>> The "ripple" on the voltage across a capacitor reflects the charge that
>> is being taken out of and fed into the capacitor over the mains cycle.
>> More capacitance means smaller ripple.
>>
>> Leakage is just the current flowing through the oxide layer on top of
>> metal conductor surfaces inside the electrolytic capacitor. If the
>> capacitor has been un-used for a long time, some of the oxide layer may
>> have diffused away, making the capacitance and the leakage current
>> higher. Applying the working voltage will re-form the oxide layer by
>> making it a bit thicker.
>>
>>> I'd like a "second opinion" as it were on the leakiness of these caps.
>>> What's the best old-school method for testing for this? I just want to
>>> ensure the ESR meter isn't faulty (highly unlikely but the possibility
>>> must be eliminated to be sure).
>>
>> If an electrolytic capacitor hasn't been used for some time, it's going
>> to be leaky. If you want to measure how leaky, measure the direct
>> current flowing through the capacitor as you increase the bias voltage
>> across it. It should drop as the oxide layer re-forms, perhaps over hours.

This might have been the information you needed, if you knew enough to
process it. The placement of your response suggests that you don't.

--
Bill Sloman, Sydney

On 5/03/2024 9:27 am, Cursitor Doom wrote:
> On Mon, 04 Mar 2024 09:20:12 -0800, John Larkin <jl@997PotHill.com>
> wrote:
>
>> On Mon, 04 Mar 2024 15:50:21 +0000, Cursitor Doom <cd@notformail.com>
>> wrote:
>>
>>> On Mon, 4 Mar 2024 15:29:02 +1100, Bill Sloman <bill.sloman@ieee.org>
>>> wrote:
>>>
>>>> On 4/03/2024 5:03 am, Cursitor Doom wrote:
>>>>> Hi all,
>>>>>
>>>>> Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>>>> checks on large electros in the linear PSU I've previously mentioned
>>>>> here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>>>> them, so I pulled them out completely and am getting the same warning
>>>>> when they're checked out of circuit, which surprised me as it's
>>>>> unusual IME. Anyway, the leak would have to be very bad to result in
>>>>> ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>>>> which have lost a significant amount of capacitance or else developed
>>>>> a very large ESR. Do I have that right?
>>>>
>>>> What you have wrong is the imagined association between leakage and ripple.
>>>
>>> Eh? I did say leakage was probably about the least likely cause of
>>> ripple!
>>
>> Don't argue. Sloman is always right and everyone else is always wrong
>> and stupid.

John Larkin and Cursitor Doom are frequently wrong. Their addiction to
certain sorts of misinformation may make them popular in their social
circles, so they aren't necessarily stupid,even if they do post a lot of
foolish nonsense

> Much of that can be accounted for by the fact that Bill doesn't bother
> reading others' comments in their entirety. He goes off 'half-cock'
> and makes an ass of himself. That doesn't say much for his claims to
> be a scientist.

A trifle ironic, given that Cursitor Doom's response was placed before
my explanation of what was going on. It wasn't all that technical, but
he still doesn't seem to have read it.

--
Bill Sloman, Sydney

On 5/03/2024 2:55 am, Cursitor Doom wrote:
> On Sun, 03 Mar 2024 18:28:46 -0800, John Larkin <jl@997PotHill.com> wrote:
>> On Mon, 04 Mar 2024 00:31:27 +0000, Cursitor Doom <cd@notformail.com> wrote:
>>> On Sun, 03 Mar 2024 16:22:12 -0800, John Larkin <jl@997PotHill.com> wrote:
>>>> On Sun, 03 Mar 2024 23:50:08 +0000, Cursitor Doom <cd@notformail.com> wrote:
>>>>> On Sun, 03 Mar 2024 15:16:12 -0800, John Larkin <jl@997PotHill.com> wrote:
>>>>>> On Sun, 03 Mar 2024 22:41:09 +0000, Cursitor Doom <cd@notformail.com> wrote:
>>>>>>> On Sun, 03 Mar 2024 13:28:05 -0800, John Larkin <jl@997PotHill.com> wrote:
>>>>>>>> On Sun, 03 Mar 2024 18:03:51 +0000, Cursitor Doom <cd@notformail.com> wrote:

<snip>

> But then how do you determine - given that electrolytics come in all
> sorts of votlage and temperature ratings, capacitance values etc - how
> much leakage current in each case is "too much" leakage current
> rendering the cap unsuitable for use?

Capacitors usually come with manufacturer's logos and part numbers.

Google should be able to find you the relevant data sheet.
For a given size, voltage rating and technology a broad-line distributor
can usually throw a similar part, and it's data sheet.
<snip>

--
Bill Sloman, Sydney

On Mon, 04 Mar 2024 16:41:40 -0800, john larkin <jl@650pot.com> wrote:

>On Mon, 04 Mar 2024 23:03:05 +0000, Cursitor Doom <cd@notformail.com>
>wrote:
>
>>On Mon, 04 Mar 2024 09:16:53 -0800, John Larkin <jl@997PotHill.com>
>>wrote:
>>
>>>On Mon, 04 Mar 2024 15:55:53 +0000, Cursitor Doom <cd@notformail.com>
>>>wrote:
>>>
>>>>On Sun, 03 Mar 2024 18:28:46 -0800, John Larkin <jl@997PotHill.com>
>>>>wrote:
>>>>
>>>>>On Mon, 04 Mar 2024 00:31:27 +0000, Cursitor Doom <cd@notformail.com>
>>>>>wrote:
>>>>>
>>>>>>On Sun, 03 Mar 2024 16:22:12 -0800, John Larkin <jl@997PotHill.com>
>>>>>>wrote:
>>>>>>
>>>>>>>On Sun, 03 Mar 2024 23:50:08 +0000, Cursitor Doom <cd@notformail.com>
>>>>>>>wrote:
>>>>>>>
>>>>>>>>On Sun, 03 Mar 2024 15:16:12 -0800, John Larkin <jl@997PotHill.com>
>>>>>>>>wrote:
>>>>>>>>
>>>>>>>>>On Sun, 03 Mar 2024 22:41:09 +0000, Cursitor Doom <cd@notformail.com>
>>>>>>>>>wrote:
>>>>>>>>>
>>>>>>>>>>On Sun, 03 Mar 2024 13:28:05 -0800, John Larkin <jl@997PotHill.com>
>>>>>>>>>>wrote:
>>>>>>>>>>
>>>>>>>>>>>On Sun, 03 Mar 2024 18:03:51 +0000, Cursitor Doom <cd@notformail.com>
>>>>>>>>>>>wrote:
>>>>>>>>>>>
>>>>>>>>>>>>Hi all,
>>>>>>>>>>>>
>>>>>>>>>>>>Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>>>>>>>>>>>checks on large electros in the linear PSU I've previously mentioned
>>>>>>>>>>>>here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>>>>>>>>>>>them, so I pulled them out completely and am getting the same warning
>>>>>>>>>>>>when they're checked out of circuit, which surprised me as it's
>>>>>>>>>>>>unusual IME. Anyway, the leak would have to be very bad to result in
>>>>>>>>>>>>ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>>>>>>>>>>>which have lost a significant amount of capacitance or else developed
>>>>>>>>>>>>a very large ESR. Do I have that right?
>>>>>>>>>>>>I'd like a "second opinion" as it were on the leakiness of these caps.
>>>>>>>>>>>>What's the best old-school method for testing for this? I just want to
>>>>>>>>>>>>ensure the ESR meter isn't faulty (highly unlikely but the possibility
>>>>>>>>>>>>must be eliminated to be sure).
>>>>>>>>>>>>
>>>>>>>>>>>>CD.
>>>>>>>>>>>>
>>>>>>>>>>>>PS: the aforementioned caps are 47000uF 16V Vishay ones - and I have a
>>>>>>>>>>>>brand new spare that's also testing as "leaky"!
>>>>>>>>>>>
>>>>>>>>>>>How leaky? You could apply 16 volts and measure current for a while.
>>>>>>>>>>>It will typically taper off over some minutes or hours.
>>>>>>>>>>
>>>>>>>>>>Well, the 'perfect cap' in series with an ammeter will cause an
>>>>>>>>>>initial surge of current which will taper off over time and eventually
>>>>>>>>>>settle at zero. But a leaky cap will continue to pass a small amount
>>>>>>>>>>of current, I would assume, indefinitely? Again, I would guess that a
>>>>>>>>>>real-world cap in good condition would continue to pass a tiny amount
>>>>>>>>>>of current - a negligible amount?
>>>>>>>>>
>>>>>>>>>An electrolytic is hardly a perfect cap. After the theoretical cap
>>>>>>>>>charge, you might see some mA of leakage, tapering off to uA's after
>>>>>>>>>some minutes or hours.
>>>>>>>>>
>>>>>>>>>If the current ever increases, as it will at some voltage above rated,
>>>>>>>>>it's probably on its way to destruction.
>>>>>>>>>
>>>>>>>>>Get a power supply and an ammeter and experiment. Your capmeter is
>>>>>>>>>obviously not telling you much.
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>Just spotted the meter only covers up to 22,000uF!
>>>>>>>>we
>>>>>>>
>>>>>>>I don't trust C or L meters, especially for large C or L values, or
>>>>>>>cheap meters.
>>>>>>
>>>>>>How would you test for leakage, then?
>>>>>
>>>>>Power supply and DVM.
>>>>
>>>>But then how do you determine - given that electrolytics come in all
>>>>sorts of votlage and temperature ratings, capacitance values etc - how
>>>>much leakage current in each case is "too much" leakage current
>>>>rendering the cap unsuitable for use?
>>>
>>>That's for you to decide. No instrument is going to have red and green
>>>LEDs to tell you if a cap is suitable for your circuit.
>>
>>That's not how cap testers work, though. They take virtually none of
>>the following into account:-
>>
>>>Gross capacitance
>>>C vs voltage
>>>C vs temperature
>>>Leakage vs temperature and voltage, both polarities
>>>Dielectric absorption
>>>Failure voltage or current
>>>ESR vs temperature
>>>ESL
>>>Lifetime
>>>Power dissipation/cooling
>>>Solderability/washability
>>>
>>>One should measure or calculate whichever of those might matter in
>>>your circuit.
>>>
>>>Post your circuit and we can talk about it.
>>
>>No circuit involved. The question relates to generic smoothing caps of
>>linear power supplies.
>
>Where in a circuit is a "smoothing" cap? Oops, sorry, there is no
>circuit.
>
>

Yes, there's no circuit. Marconi/Aeroflex never published one and and
a lot of their designs are still under wraps. It's a real PITA.

On Tue, 5 Mar 2024 12:52:04 +1100, Bill Sloman <bill.sloman@ieee.org>
wrote:

>On 5/03/2024 2:50 am, Cursitor Doom wrote:
>> On Mon, 4 Mar 2024 15:29:02 +1100, Bill Sloman <bill.sloman@ieee.org>
>> wrote:
>>
>>> On 4/03/2024 5:03 am, Cursitor Doom wrote:
>>>> Hi all,
>>>>
>>>> Using my Peak ESR/Capacitance meter, I was carrying out in-circuit
>>>> checks on large electros in the linear PSU I've previously mentioned
>>>> here. I was getting a lot of "in-circuit/leaky" warnings for two of
>>>> them, so I pulled them out completely and am getting the same warning
>>>> when they're checked out of circuit, which surprised me as it's
>>>> unusual IME. Anyway, the leak would have to be very bad to result in
>>>> ripple, would it not? AFAIK, the leading culprit for ripple is caps
>>>> which have lost a significant amount of capacitance or else developed
>>>> a very large ESR. Do I have that right?
>>>
>>> What you have wrong is the imagined association between leakage and ripple.
>>
>> Eh? I did say leakage was probably about the least likely cause of
>> ripple!
>
>The error comes from imagining that the two were connected.

How's the weather on Planet Sloman today, Bill?
>
>>> The "ripple" on the voltage across a capacitor reflects the charge that
>>> is being taken out of and fed into the capacitor over the mains cycle.
>>> More capacitance means smaller ripple.
>>>
>>> Leakage is just the current flowing through the oxide layer on top of
>>> metal conductor surfaces inside the electrolytic capacitor. If the
>>> capacitor has been un-used for a long time, some of the oxide layer may
>>> have diffused away, making the capacitance and the leakage current
>>> higher. Applying the working voltage will re-form the oxide layer by
>>> making it a bit thicker.
>>>
>>>> I'd like a "second opinion" as it were on the leakiness of these caps.
>>>> What's the best old-school method for testing for this? I just want to
>>>> ensure the ESR meter isn't faulty (highly unlikely but the possibility
>>>> must be eliminated to be sure).
>>>
>>> If an electrolytic capacitor hasn't been used for some time, it's going
>>> to be leaky. If you want to measure how leaky, measure the direct
>>> current flowing through the capacitor as you increase the bias voltage
>>> across it. It should drop as the oxide layer re-forms, perhaps over hours.
>
>This might have been the information you needed, if you knew enough to
>process it. The placement of your response suggests that you don't.

Your remarks were so trite they didn't bear a response. Everyone here
knows electrolytic caps need to be re-formed if they've been unsused
for any significant length of time. It's vintage scope repair 101 and
even you must be aware restoring vintage scopes is my prime interest
in the subject. God knows I've posted enough about it over the years!

On 5/03/2024 8:30 pm, Cursitor Doom wrote:
> On Tue, 5 Mar 2024 12:52:04 +1100, Bill Sloman <bill.sloman@ieee.org> wrote:
>> On 5/03/2024 2:50 am, Cursitor Doom wrote:
>>> On Mon, 4 Mar 2024 15:29:02 +1100, Bill Sloman <bill.sloman@ieee.org> wrote:
>>>> On 4/03/2024 5:03 am, Cursitor Doom wrote:

<snip>

>> This might have been the information you needed, if you knew enough to
>> process it. The placement of your response suggests that you don't.
>
> Your remarks were so trite they didn't bear a response. Everyone here
> knows electrolytic caps need to be re-formed if they've been unused
> for any significant length of time.

But you didn't mention it in your original post, and clearly don't
appreciate what it is actually doing.

> It's vintage scope repair 101 and even you must be aware restoring vintage scopes is my prime interest
> in the subject. God knows I've posted enough about it over the years!

I'm sure you know about it as a ritual you have learned to perform. You
didn't actually comprehend what you were doing, any more than you did
when you acted out what you thought was researching the climate change
literature, and were actually performing a trawl through the unreliable
early results to cherry-pick those few results that suited your daft
hypothesis.

--
Bill Sloman, Sydney