Re: [time-nuts] Low noise power supply recommendations

[Will Matney]

Thanks Hal, and Henry, I was wondering about how they acted. I have really
nver studied them that much for this type of application. Of course, I have
some old moon filters laying around, that are a very low shade, and I could
cut up. That could work without having to play with the LED's.

Thanks,

Will

*** REPLY SEPARATOR  ***

On 6/15/2011 at 8:19 PM ehydra wrote:

>There get slower with falling current.
>
>- Henry
>
>
>-- 
>ehydra.dyndns.info
>
>
>
>Hal Murray schrieb:
>>> I was thinking about trying an orange or yellow LED here, and dimming
the
>>> LED with the series resistor, trying to make it as dim as the neon
bulb, but
>>> I don't know if a LED can be dimmed down that low.
>> 
>> LEDs work fine at low output levels.  At low current, the light output
is 
>> linear with current.  It falls off at high current and/or high
temperature.
>> 
>> 
>> 
>
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Re: [time-nuts] Low noise power supply recommendations

[ehydra]

There get slower with falling current.

- Henry


--
ehydra.dyndns.info



Hal Murray schrieb:

I was thinking about trying an orange or yellow LED here, and dimming the
LED with the series resistor, trying to make it as dim as the neon bulb, but
I don't know if a LED can be dimmed down that low.


LEDs work fine at low output levels.  At low current, the light output is 
linear with current.  It falls off at high current and/or high temperature.






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Re: [time-nuts] Low noise power supply recommendations

[Hal Murray]

> I was thinking about trying an orange or yellow LED here, and dimming the
> LED with the series resistor, trying to make it as dim as the neon bulb, but
> I don't know if a LED can be dimmed down that low.

LEDs work fine at low output levels.  At low current, the light output is 
linear with current.  It falls off at high current and/or high temperature.



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Re: [time-nuts] Low noise power supply recommendations

[J. Forster]

> John,
>
> They used Lucite rods, I shouldn't have said tubes. The neon bulbs are
> about at the center of the PC board, and the CDS cells are at the edge, so
> to get the light to them, they used the rods.

More than that. They wanted to minimize capacitance coupled between the
neons and cells to reducing switching spikes.

> I think they did the same
> thing on the 845AB too, but I'm not looking at the manual right now to see
> for sure, as I'm not sure the 844 and 845 use the same PC board, just the
> same circuitry. The 844 was sold to other manufacturers, and it came in a
> plain aluminum box, with the switch shaft sticking out the front. The
> meter
> and pots were shipped seperate to be mounted in the customers equipment.
> HP
> did the same with the 419, and tacked another letter on the model number,
> as well as Keithly, which I know uses the same PC board in both versions.
> Keithly didn't use this type of chopper though (using LED's or lamps).
>
> I am going to locate the post on the HP forum and read about it. My guess
> is that the LED's brightness helped kill the CDS cells.

I don't think so. Apparently the CdS cells had aged into uselessness
before any LEDS were installed. Read the thread.


> I was thinking
> about trying an orange or yellow LED here, and dimming the LED with the
> series resistor, trying to make it as dim as the neon bulb, but I don't
> know if a LED can be dimmed down that low. On the old HP 412 VTVM, the
> incandescent bulbs in it were not very bright, and they were using CDS
> cells with them. Another instance of this, if I recall, was that Tektronix
> used a chopper like this in one of their older scope calibrators.
>
> Thanks,
>
> Will

Good luck,

-John

==


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Re: [time-nuts] Low noise power supply recommendations

[Will Matney]

Paul,

No, not the direct light emitted from the LED, but the extra current the
cell passed was probably over their limit. I thought of placing the LED's
vertical to the Lucite rods, instead of horizontal, or head-on, to decrease
the intensity. From the side, a LED, it's much dimmer. The NE-3 bulbs are
placed this way, but that's about the only way to get the most intensity
from them. Another thought would be to place a filter between the LED's and
the rods to dim them down.

What I was going to do was measure the voltage across the CDS cells, with
the neon bulbs running, and try to get a LED to create the same voltage
drop, or same amount of current through the cell.

Best,

Will

*** REPLY SEPARATOR  ***

On 6/15/2011 at 2:25 PM Poul-Henning Kamp wrote:

>In message <201106151021530546.2070a...@smtp.citynet.net>, "Will Matney"
writes
>:
>
>>My guess is that the LED's brightness helped kill the CDS cells. 
>
>That is not possible by direct effect, light does not hurt CDS cells.
>
>It is far more likely that more intense light than designed has decreased
>the CDS' resistance causing higher current than was good for them.
>
>
>-- 
>Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
>p...@freebsd.org | TCP/IP since RFC 956
>FreeBSD committer   | BSD since 4.3-tahoe
>Never attribute to malice what can adequately be explained by
incompetence.
>
>__ Information from ESET Smart Security, version of virus
signature database 5851 (20110206) __
>
>The message was checked by ESET Smart Security.
>
>http://www.eset.com




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Re: [time-nuts] Low noise power supply recommendations

[Poul-Henning Kamp]

In message <201106151021530546.2070a...@smtp.citynet.net>, "Will Matney" writes
:

>My guess is that the LED's brightness helped kill the CDS cells. 

That is not possible by direct effect, light does not hurt CDS cells.

It is far more likely that more intense light than designed has decreased
the CDS' resistance causing higher current than was good for them.


-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

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Re: [time-nuts] Low noise power supply recommendations

[Will Matney]

John,

They used Lucite rods, I shouldn't have said tubes. The neon bulbs are
about at the center of the PC board, and the CDS cells are at the edge, so
to get the light to them, they used the rods. I think they did the same
thing on the 845AB too, but I'm not looking at the manual right now to see
for sure, as I'm not sure the 844 and 845 use the same PC board, just the
same circuitry. The 844 was sold to other manufacturers, and it came in a
plain aluminum box, with the switch shaft sticking out the front. The meter
and pots were shipped seperate to be mounted in the customers equipment. HP
did the same with the 419, and tacked another letter on the model number,
as well as Keithly, which I know uses the same PC board in both versions.
Keithly didn't use this type of chopper though (using LED's or lamps).

I am going to locate the post on the HP forum and read about it. My guess
is that the LED's brightness helped kill the CDS cells. I was thinking
about trying an orange or yellow LED here, and dimming the LED with the
series resistor, trying to make it as dim as the neon bulb, but I don't
know if a LED can be dimmed down that low. On the old HP 412 VTVM, the
incandescent bulbs in it were not very bright, and they were using CDS
cells with them. Another instance of this, if I recall, was that Tektronix
used a chopper like this in one of their older scope calibrators.

Thanks,

Will

*** REPLY SEPARATOR  ***

On 6/15/2011 at 6:51 AM J. Forster wrote:

>> John,
>>
>> I will check it out, and may do some experiments myself on these. Also,
I
>> will take a look at the photo-FET's, as I had forgotten about those.
>>
>> What has me wondering is how neon bulbs act in the circuit, their low
>> brightness, and their drop out times, as I think the on voltage is
around
>> 90 volts or so,
>
>More like 70. They need a higher voltage to turn on (strike).
>
>> but the square wave going to them is around 100-115 volts
>> if I recall. I thought about using a simple 10:1 resistive divider, then
>> using a series resistor from that junction going to the LED, the same as
>> for a 10-15 volt supply.
>
>Neons run at very low currents.
>
>> The neon bulbs light goes through two Lucite tubes
>> to the CDS cells, and it couldn't be too bright by the time it reached
>> them.
>
>Tubes or rods (as a light guide)?
>
>> I also thought about using a new form of chopper, as Paul mentions, but
>> making it fit and work could get complicated. ESI quit using the HP 419
in
>> the last models of their 801 DC supply and detector-null meter, and
>> started
>> using a Keithly 155. I either figured it was over this very thing, or HP
>> dropped the 419 from its line. An engineer at Vishay told me that they
>> quit
>> using the Fluke over this neon problem, and went to the Keithly in the
>> last
>> versions of this bridge.
>
>OK.
>
>> I'm going to be using the bridge not only as it was intended, but to do
>> other null measurements, as I added a circuit to use the meter circuit
>> seperatly from the bridge.
>>
>> Thanks,
>>
>> Will
>
>Good luck. BTW, the HP thread referred to degradation of the CdS cells.
>You should read it. It is possible to makle a very high Z chopper with
>CdS. I'm not so sure about other ways.
>
>-John
>
>
>
>
>__ Information from ESET Smart Security, version of virus
signature database 5851 (20110206) __
>
>The message was checked by ESET Smart Security.
>
>http://www.eset.com




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Re: [time-nuts] Low noise power supply recommendations

[J. Forster]

> John,
>
> I will check it out, and may do some experiments myself on these. Also, I
> will take a look at the photo-FET's, as I had forgotten about those.
>
> What has me wondering is how neon bulbs act in the circuit, their low
> brightness, and their drop out times, as I think the on voltage is around
> 90 volts or so,

More like 70. They need a higher voltage to turn on (strike).

> but the square wave going to them is around 100-115 volts
> if I recall. I thought about using a simple 10:1 resistive divider, then
> using a series resistor from that junction going to the LED, the same as
> for a 10-15 volt supply.

Neons run at very low currents.

> The neon bulbs light goes through two Lucite tubes
> to the CDS cells, and it couldn't be too bright by the time it reached
> them.

Tubes or rods (as a light guide)?

> I also thought about using a new form of chopper, as Paul mentions, but
> making it fit and work could get complicated. ESI quit using the HP 419 in
> the last models of their 801 DC supply and detector-null meter, and
> started
> using a Keithly 155. I either figured it was over this very thing, or HP
> dropped the 419 from its line. An engineer at Vishay told me that they
> quit
> using the Fluke over this neon problem, and went to the Keithly in the
> last
> versions of this bridge.

OK.

> I'm going to be using the bridge not only as it was intended, but to do
> other null measurements, as I added a circuit to use the meter circuit
> seperatly from the bridge.
>
> Thanks,
>
> Will

Good luck. BTW, the HP thread referred to degradation of the CdS cells.
You should read it. It is possible to makle a very high Z chopper with
CdS. I'm not so sure about other ways.

-John




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Re: [time-nuts] Low noise power supply recommendations

[paul swed]

Well a couple of thoughts.
As I said modern choppers do work and have big pluses these days.
But to the neon bulb.
I would use a led thats color more approximates neon. They make them.
I rebuilt a HP5360 counter /nixie with modern 7 seg leds that matched the
nixie color and it turned out very well. The photo resistors are touchy. The
older HP counters actually used neons and photo resistors in the decade
counters as the binary to decimal converters. The neon is not standard. Its
shorter, typical neons will not fit.
My O my has this drifted back to wwvb.
Regards
Paul




On Wed, Jun 15, 2011 at 7:49 AM, Will Matney  wrote:

> Bruce,
>
> Correct, and by adding the series resistor for higher impedance, the
> voltage regulation at the zener value is raised from 10 volts to some value
> higher. I actually remember a variable bias control to a tube using a
> similar circuit, except the fixed resistor was a pot. He shows using this
> on a shunt regulator also on the following page. How much unstability this
> causes at the value given is unknown without actually building the circuit
> and testing it, but one shouldn't use a series resistor with a zener this
> way. I remember Rich Measures and myself speaking of this a few years back.
>
> One thing that's not mentioned in the article is that certain resistors can
> cause noise by themselves. Good articles on this are in some power supply
> and voltage reference App Notes from both Linear Tech., and National.
>
> Best,
>
> Will
>
> *** REPLY SEPARATOR  ***
>
> On 6/15/2011 at 6:59 PM Bruce Griffiths wrote:
>
> >Will Matney wrote:
> >> As far as the power supply is concerned, I think I am going to go with
> >> Ni-Cad batteries, and regulate the voltages. I think what they had was
> >> nothing more than four step voltages from the battery supply, going from
> 3,
> >> 6 (7), 12, and 24 Vdc, or X2 of the other. From what I saw in the
> article
> >> earlier, an easy zener with emotter follower regulator should do the
> trick
> >> by the comparison with batteries. They used some resistance in series
> with
> >> the zener to reduce noise, but it did decrease the stability somewhat. I
> >> have seen this used in some old bias regulation circuits for tubes years
> >> ago.
> >>
> >>
> >A somewhat misguided idea, they really should have used an RC low pass
> >filter between the zener and the output transistor base.
> >The filtering effect is the same but without significantly decreased
> >stability over that of an unfiltered zener..
> >> As far as the noise, I also wondered about this, as ESI used a current
> >> limited DC power source to do the same thing, and it was ran off the AC
> >> line.
> >>
> >> Thanks,
> >>
> >> Will
> >>
> >> *** REPLY SEPARATOR  ***
> >>
> >Bruce
> >
> >__ Information from ESET Smart Security, version of virus
> signature database 5851 (20110206) __
> >
> >The message was checked by ESET Smart Security.
> >
> >http://www.eset.com
>
>
>
>
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Re: [time-nuts] Low noise power supply recommendations

[Will Matney]

Bruce,

Correct, and by adding the series resistor for higher impedance, the
voltage regulation at the zener value is raised from 10 volts to some value
higher. I actually remember a variable bias control to a tube using a
similar circuit, except the fixed resistor was a pot. He shows using this
on a shunt regulator also on the following page. How much unstability this
causes at the value given is unknown without actually building the circuit
and testing it, but one shouldn't use a series resistor with a zener this
way. I remember Rich Measures and myself speaking of this a few years back.

One thing that's not mentioned in the article is that certain resistors can
cause noise by themselves. Good articles on this are in some power supply
and voltage reference App Notes from both Linear Tech., and National.

Best,

Will

*** REPLY SEPARATOR  ***

On 6/15/2011 at 6:59 PM Bruce Griffiths wrote:

>Will Matney wrote:
>> As far as the power supply is concerned, I think I am going to go with
>> Ni-Cad batteries, and regulate the voltages. I think what they had was
>> nothing more than four step voltages from the battery supply, going from
3,
>> 6 (7), 12, and 24 Vdc, or X2 of the other. From what I saw in the
article
>> earlier, an easy zener with emotter follower regulator should do the
trick
>> by the comparison with batteries. They used some resistance in series
with
>> the zener to reduce noise, but it did decrease the stability somewhat. I
>> have seen this used in some old bias regulation circuits for tubes years
>> ago.
>>
>>
>A somewhat misguided idea, they really should have used an RC low pass 
>filter between the zener and the output transistor base.
>The filtering effect is the same but without significantly decreased 
>stability over that of an unfiltered zener..
>> As far as the noise, I also wondered about this, as ESI used a current
>> limited DC power source to do the same thing, and it was ran off the AC
>> line.
>>
>> Thanks,
>>
>> Will
>>
>> *** REPLY SEPARATOR  ***
>>
>Bruce
>
>__ Information from ESET Smart Security, version of virus
signature database 5851 (20110206) __
>
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>
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Re: [time-nuts] Low noise power supply recommendations

[Bruce Griffiths]

Will Matney wrote:

As far as the power supply is concerned, I think I am going to go with
Ni-Cad batteries, and regulate the voltages. I think what they had was
nothing more than four step voltages from the battery supply, going from 3,
6 (7), 12, and 24 Vdc, or X2 of the other. From what I saw in the article
earlier, an easy zener with emotter follower regulator should do the trick
by the comparison with batteries. They used some resistance in series with
the zener to reduce noise, but it did decrease the stability somewhat. I
have seen this used in some old bias regulation circuits for tubes years
ago.

   
A somewhat misguided idea, they really should have used an RC low pass 
filter between the zener and the output transistor base.
The filtering effect is the same but without significantly decreased 
stability over that of an unfiltered zener..

As far as the noise, I also wondered about this, as ESI used a current
limited DC power source to do the same thing, and it was ran off the AC
line.

Thanks,

Will

*** REPLY SEPARATOR  ***
   

Bruce

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Re: [time-nuts] Low noise power supply recommendations

[Will Matney]

John,

I will check it out, and may do some experiments myself on these. Also, I
will take a look at the photo-FET's, as I had forgotten about those.

What has me wondering is how neon bulbs act in the circuit, their low
brightness, and their drop out times, as I think the on voltage is around
90 volts or so, but the square wave going to them is around 100-115 volts
if I recall. I thought about using a simple 10:1 resistive divider, then
using a series resistor from that junction going to the LED, the same as
for a 10-15 volt supply. The neon bulbs light goes through two Lucite tubes
to the CDS cells, and it couldn't be too bright by the time it reached
them.

I also thought about using a new form of chopper, as Paul mentions, but
making it fit and work could get complicated. ESI quit using the HP 419 in
the last models of their 801 DC supply and detector-null meter, and started
using a Keithly 155. I either figured it was over this very thing, or HP
dropped the 419 from its line. An engineer at Vishay told me that they quit
using the Fluke over this neon problem, and went to the Keithly in the last
versions of this bridge.

I'm going to be using the bridge not only as it was intended, but to do
other null measurements, as I added a circuit to use the meter circuit
seperatly from the bridge.

Thanks,

Will

*** REPLY SEPARATOR  ***

On 6/14/2011 at 8:13 PM J. Forster wrote:

>Hi Will,
>
>I don't know. Check the HP Group archives. I only vaguely followed the
>thread. I'm not so sure a phototransistor will work without circuit mods.
>A photoFET might.
>
>Best,
>
>-John
>
>===
>
>
>> John,
>>
>> I wondered about that, as using a LED is generally in conjunction with a
>> photo-transistor, and not a CDS cell. The reason I thought it might work
>> is
>> that a company years back used them together to form a safety light
>> curtain.
>>
>> The Fluke, and the HP, had a bad rep for those neon bulbs going out and
>> having to be replaced. I am going to replace the ones in the 844 before
I
>> button it up, but was wondering if something else could be done. I
looked
>> up the life cycle for the NE-3 and it's kind of low, especially compared
>> to
>> a LED. I imagine the problem has to do with the brightness of the LED,
as
>> compared to a neon bulb, when using a CDS cell.
>>
>> As far as the power supply is concerned, I think I am going to go with
>> Ni-Cad batteries, and regulate the voltages. I think what they had was
>> nothing more than four step voltages from the battery supply, going from
>> 3,
>> 6 (7), 12, and 24 Vdc, or X2 of the other. From what I saw in the
article
>> earlier, an easy zener with emotter follower regulator should do the
trick
>> by the comparison with batteries. They used some resistance in series
with
>> the zener to reduce noise, but it did decrease the stability somewhat. I
>> have seen this used in some old bias regulation circuits for tubes years
>> ago.
>>
>> As far as the noise, I also wondered about this, as ESI used a current
>> limited DC power source to do the same thing, and it was ran off the AC
>> line.
>>
>> Thanks,
>>
>> Will
>>
>> *** REPLY SEPARATOR  ***
>>
>> On 6/14/2011 at 7:14 PM J. Forster wrote:
>>
>>>The reason I asked is that most microvolt bridges use choppers and have
>>> BP
>>>filters at the chopper frequency, so noise is largely uncorrelated.
>>>
>>>On the neon photochoppers, it has been discussed at length several times
>>>on the HP-Agilent Yahyoo Group. A similar thing is used in the 410C.
>>> There
>>>are apparently issues with the CdS cells.
>>>
>>>Best,
>>>
>>>-John
>>>
>>>===
>>>
>>>
 John,

 No, it's DC. I'm trying to meet the original specs of the batteries in
>> not
 only voltage/current, but cleanliness of the current.

 Now inside the Fluke 844, it has a chopper, and it uses an AC power
>> supply
 internally to feed its circuitry. The Vishays bridge uses the
batteries
 voltage, and one small AC power supply to run the digital portion of
 the
 bridge for the PPM readout. The bridge itself is half analog and half
 digital. The analog for the measurement, and the digital for the PPM
 difference.

 By the way, has anyone ever converted a neon NE-3 driven chopper to
>> using
 LED's? The bulbs have a sqaure wave coming into them of around 100-200
>> Hz
 if I recall.

 Thanks,

 Will

 *** REPLY SEPARATOR  ***

 On 6/14/2011 at 6:50 PM J. Forster wrote:

>Is the bridge excitation AC or DC. If it's AC, you may not even need
>low-noise power supplies.
>
>-John
>
>==
>
>
>
>> Hi Will,
>>
>> You could consider building your own power supply system for the
>> replacement of
>> the batteries.  Use a separate power transformer which, I suspect,
>> would
>> be small
>> as the current requirements would be low for drivin

Re: [time-nuts] Low noise power supply recommendations

[Will Matney]

Paul,

Remember the HP 412? It used incandescent bulbs, a spinning disc, and a
syncronous motor. I actually still use two of these, and the bulbs are the
only fault.

Getting back on topic, somewhat, has anyone ever checked the noise on the
rails feeding the OCXO's in this GPS equipment? Especially the ones ruiing
off 12 volt car lead-acid batteries?

The reason for the question is, I was always taught that batteries were the
best souce, when noise or cleaness of supply voltage was needed. It was
never stated which battery to use, etc. From the article, it said that
alkaline batteries had a cleaner supply than others, but then again, their
not rechargable. Does anyone remember anything about the mercury batteries?

Best,

Will

*** REPLY SEPARATOR  ***

On 6/14/2011 at 10:21 PM paul swed wrote:

>Though its a bit off topic
>Ran into this chopper issue also on a HP410. I replaced the thing with a
>modern chopper amp. I think an LTC. This was quite a few years ago (10
plus
>easily) and it works very well. Still does actually. It did take a bit of
>rework to get things back in balance correctly.
>
>On Tue, Jun 14, 2011 at 10:14 PM, J. Forster  wrote:
>
>> The reason I asked is that most microvolt bridges use choppers and have
BP
>> filters at the chopper frequency, so noise is largely uncorrelated.
>>
>> On the neon photochoppers, it has been discussed at length several times
>> on the HP-Agilent Yahyoo Group. A similar thing is used in the 410C.
There
>> are apparently issues with the CdS cells.
>>
>> Best,
>>
>> -John
>>
>> ===
>>
>>
>> > John,
>> >
>> > No, it's DC. I'm trying to meet the original specs of the batteries in
>> not
>> > only voltage/current, but cleanliness of the current.
>> >
>> > Now inside the Fluke 844, it has a chopper, and it uses an AC power
>> supply
>> > internally to feed its circuitry. The Vishays bridge uses the
batteries
>> > voltage, and one small AC power supply to run the digital portion of
the
>> > bridge for the PPM readout. The bridge itself is half analog and half
>> > digital. The analog for the measurement, and the digital for the PPM
>> > difference.
>> >
>> > By the way, has anyone ever converted a neon NE-3 driven chopper to
using
>> > LED's? The bulbs have a sqaure wave coming into them of around 100-200
Hz
>> > if I recall.
>> >
>> > Thanks,
>> >
>> > Will
>> >
>> > *** REPLY SEPARATOR  ***
>> >
>> > On 6/14/2011 at 6:50 PM J. Forster wrote:
>> >
>> >>Is the bridge excitation AC or DC. If it's AC, you may not even need
>> >>low-noise power supplies.
>> >>
>> >>-John
>> >>
>> >>==
>> >>
>> >>
>> >>
>> >>> Hi Will,
>> >>>
>> >>> You could consider building your own power supply system for the
>> >>> replacement of
>> >>> the batteries.  Use a separate power transformer which, I suspect,
>> >>> would
>> >>> be small
>> >>> as the current requirements would be low for driving a bridge
circuit.
>> >>>
>> >>> The main company to look toward for high quality, low noise
regulators
>> > is
>> >>> Linear
>> >>> Technology.  Here is a candidate part to look at :
>> >>> http://www.linear.com/product/LT3082
>> >>>
>> >>> This is the lowest noise (33uv/10Hz to 100KHz) low dropout regulator
>> > that
>> >>> can
>> >>> handle regulating 24 volts and is adjustable, meaning use can use
this
>> >>> part for
>> >>> all three voltages (i.e., three regulators).  You will have to
decide
>> >>> if
>> >>> it noise
>> >>> specs are suitable for your needs.  Keep in mind that battery noise
is
>> >>> typically
>> >>> random whereas the noise out of a regulated system tends to be
>> >>> constant.
>> >>>
>> >>> If you really think you need lower noise then you could consider an
>> > LT1000
>> >>> shunt
>> >>> reference.  Typically the circuit designs for LT1000 type devices
are
>> >>> as
>> >>> references and lack current capability above about 10 milliamps.
>> >>> Adding
>> >>> additional current circuitry would add more noise.  See:
>> >>>
>> >>> http://www.linear.com/product/LTZ1000
>> >>>
>> >>>
>> >>> BillWB6BNQ
>> >>>
>> >>>
>> >>> Will Matney wrote:
>> >>>
>>  Hello,
>> 
>>  I am in need of a very clean 24 Vdc power source, to replace some
old
>>  mercury cell batteries with. What would a good low noise, clean,
power
>>  supply be in your recommendations? I thought of using two 12 Vdc
>>  lead-acid
>>  batteries in series, and making a charging circuit with regulators,
>>  but
>>  I
>>  am hoping to purchase a good used supply off ebay, etc. The old
>>  circuit
>>  used two 12 Vdc snap terminal mercury batteries in series, for 24
Vdc,
>>  along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc
>>  batteries
>>  in series for 3 volts. Any help and or ideas would be appreciated.
>> 
>>  Thanks
>> 
>>  Will
>> 
>>  ___
>>  time-nuts mailing list -- time-nuts@febo.com
>>  To unsubscribe, g

Re: [time-nuts] Low noise power supply recommendations

[Will Matney]

Paul,

Remember the HP 412? It used incandescent bulbs, a spinning disc, and a
syncronous motor. I actually still use two of these, and the bulbs are the
only fault.

Best,

Will

*** REPLY SEPARATOR  ***

On 6/14/2011 at 10:21 PM paul swed wrote:

>Though its a bit off topic
>Ran into this chopper issue also on a HP410. I replaced the thing with a
>modern chopper amp. I think an LTC. This was quite a few years ago (10
plus
>easily) and it works very well. Still does actually. It did take a bit of
>rework to get things back in balance correctly.
>
>On Tue, Jun 14, 2011 at 10:14 PM, J. Forster  wrote:
>
>> The reason I asked is that most microvolt bridges use choppers and have
BP
>> filters at the chopper frequency, so noise is largely uncorrelated.
>>
>> On the neon photochoppers, it has been discussed at length several times
>> on the HP-Agilent Yahyoo Group. A similar thing is used in the 410C.
There
>> are apparently issues with the CdS cells.
>>
>> Best,
>>
>> -John
>>
>> ===
>>
>>
>> > John,
>> >
>> > No, it's DC. I'm trying to meet the original specs of the batteries in
>> not
>> > only voltage/current, but cleanliness of the current.
>> >
>> > Now inside the Fluke 844, it has a chopper, and it uses an AC power
>> supply
>> > internally to feed its circuitry. The Vishays bridge uses the
batteries
>> > voltage, and one small AC power supply to run the digital portion of
the
>> > bridge for the PPM readout. The bridge itself is half analog and half
>> > digital. The analog for the measurement, and the digital for the PPM
>> > difference.
>> >
>> > By the way, has anyone ever converted a neon NE-3 driven chopper to
using
>> > LED's? The bulbs have a sqaure wave coming into them of around 100-200
Hz
>> > if I recall.
>> >
>> > Thanks,
>> >
>> > Will
>> >
>> > *** REPLY SEPARATOR  ***
>> >
>> > On 6/14/2011 at 6:50 PM J. Forster wrote:
>> >
>> >>Is the bridge excitation AC or DC. If it's AC, you may not even need
>> >>low-noise power supplies.
>> >>
>> >>-John
>> >>
>> >>==
>> >>
>> >>
>> >>
>> >>> Hi Will,
>> >>>
>> >>> You could consider building your own power supply system for the
>> >>> replacement of
>> >>> the batteries.  Use a separate power transformer which, I suspect,
>> >>> would
>> >>> be small
>> >>> as the current requirements would be low for driving a bridge
circuit.
>> >>>
>> >>> The main company to look toward for high quality, low noise
regulators
>> > is
>> >>> Linear
>> >>> Technology.  Here is a candidate part to look at :
>> >>> http://www.linear.com/product/LT3082
>> >>>
>> >>> This is the lowest noise (33uv/10Hz to 100KHz) low dropout regulator
>> > that
>> >>> can
>> >>> handle regulating 24 volts and is adjustable, meaning use can use
this
>> >>> part for
>> >>> all three voltages (i.e., three regulators).  You will have to
decide
>> >>> if
>> >>> it noise
>> >>> specs are suitable for your needs.  Keep in mind that battery noise
is
>> >>> typically
>> >>> random whereas the noise out of a regulated system tends to be
>> >>> constant.
>> >>>
>> >>> If you really think you need lower noise then you could consider an
>> > LT1000
>> >>> shunt
>> >>> reference.  Typically the circuit designs for LT1000 type devices
are
>> >>> as
>> >>> references and lack current capability above about 10 milliamps.
>> >>> Adding
>> >>> additional current circuitry would add more noise.  See:
>> >>>
>> >>> http://www.linear.com/product/LTZ1000
>> >>>
>> >>>
>> >>> BillWB6BNQ
>> >>>
>> >>>
>> >>> Will Matney wrote:
>> >>>
>>  Hello,
>> 
>>  I am in need of a very clean 24 Vdc power source, to replace some
old
>>  mercury cell batteries with. What would a good low noise, clean,
power
>>  supply be in your recommendations? I thought of using two 12 Vdc
>>  lead-acid
>>  batteries in series, and making a charging circuit with regulators,
>>  but
>>  I
>>  am hoping to purchase a good used supply off ebay, etc. The old
>>  circuit
>>  used two 12 Vdc snap terminal mercury batteries in series, for 24
Vdc,
>>  along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc
>>  batteries
>>  in series for 3 volts. Any help and or ideas would be appreciated.
>> 
>>  Thanks
>> 
>>  Will
>> 
>>  ___
>>  time-nuts mailing list -- time-nuts@febo.com
>>  To unsubscribe, go to
>>  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>  and follow the instructions there.
>> >>>
>> >>>
>> >>> ___
>> >>> time-nuts mailing list -- time-nuts@febo.com
>> >>> To unsubscribe, go to
>> >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> >>> and follow the instructions there.
>> >>>
>> >>>
>> >>
>> >>
>> >>
>> >>___
>> >>time-nuts mailing list -- time-nuts@febo.com
>> >>To unsubscribe, go to
>> > https://www.febo.com/cgi

Re: [time-nuts] Low noise power supply recommendations

[J. Forster]

Hi Will,

I don't know. Check the HP Group archives. I only vaguely followed the
thread. I'm not so sure a phototransistor will work without circuit mods.
A photoFET might.

Best,

-John

===


> John,
>
> I wondered about that, as using a LED is generally in conjunction with a
> photo-transistor, and not a CDS cell. The reason I thought it might work
> is
> that a company years back used them together to form a safety light
> curtain.
>
> The Fluke, and the HP, had a bad rep for those neon bulbs going out and
> having to be replaced. I am going to replace the ones in the 844 before I
> button it up, but was wondering if something else could be done. I looked
> up the life cycle for the NE-3 and it's kind of low, especially compared
> to
> a LED. I imagine the problem has to do with the brightness of the LED, as
> compared to a neon bulb, when using a CDS cell.
>
> As far as the power supply is concerned, I think I am going to go with
> Ni-Cad batteries, and regulate the voltages. I think what they had was
> nothing more than four step voltages from the battery supply, going from
> 3,
> 6 (7), 12, and 24 Vdc, or X2 of the other. From what I saw in the article
> earlier, an easy zener with emotter follower regulator should do the trick
> by the comparison with batteries. They used some resistance in series with
> the zener to reduce noise, but it did decrease the stability somewhat. I
> have seen this used in some old bias regulation circuits for tubes years
> ago.
>
> As far as the noise, I also wondered about this, as ESI used a current
> limited DC power source to do the same thing, and it was ran off the AC
> line.
>
> Thanks,
>
> Will
>
> *** REPLY SEPARATOR  ***
>
> On 6/14/2011 at 7:14 PM J. Forster wrote:
>
>>The reason I asked is that most microvolt bridges use choppers and have
>> BP
>>filters at the chopper frequency, so noise is largely uncorrelated.
>>
>>On the neon photochoppers, it has been discussed at length several times
>>on the HP-Agilent Yahyoo Group. A similar thing is used in the 410C.
>> There
>>are apparently issues with the CdS cells.
>>
>>Best,
>>
>>-John
>>
>>===
>>
>>
>>> John,
>>>
>>> No, it's DC. I'm trying to meet the original specs of the batteries in
> not
>>> only voltage/current, but cleanliness of the current.
>>>
>>> Now inside the Fluke 844, it has a chopper, and it uses an AC power
> supply
>>> internally to feed its circuitry. The Vishays bridge uses the batteries
>>> voltage, and one small AC power supply to run the digital portion of
>>> the
>>> bridge for the PPM readout. The bridge itself is half analog and half
>>> digital. The analog for the measurement, and the digital for the PPM
>>> difference.
>>>
>>> By the way, has anyone ever converted a neon NE-3 driven chopper to
> using
>>> LED's? The bulbs have a sqaure wave coming into them of around 100-200
> Hz
>>> if I recall.
>>>
>>> Thanks,
>>>
>>> Will
>>>
>>> *** REPLY SEPARATOR  ***
>>>
>>> On 6/14/2011 at 6:50 PM J. Forster wrote:
>>>
Is the bridge excitation AC or DC. If it's AC, you may not even need
low-noise power supplies.

-John

==



> Hi Will,
>
> You could consider building your own power supply system for the
> replacement of
> the batteries.  Use a separate power transformer which, I suspect,
> would
> be small
> as the current requirements would be low for driving a bridge
> circuit.
>
> The main company to look toward for high quality, low noise
> regulators
>>> is
> Linear
> Technology.  Here is a candidate part to look at :
> http://www.linear.com/product/LT3082
>
> This is the lowest noise (33uv/10Hz to 100KHz) low dropout regulator
>>> that
> can
> handle regulating 24 volts and is adjustable, meaning use can use
> this
> part for
> all three voltages (i.e., three regulators).  You will have to decide
> if
> it noise
> specs are suitable for your needs.  Keep in mind that battery noise
> is
> typically
> random whereas the noise out of a regulated system tends to be
> constant.
>
> If you really think you need lower noise then you could consider an
>>> LT1000
> shunt
> reference.  Typically the circuit designs for LT1000 type devices are
> as
> references and lack current capability above about 10 milliamps.
> Adding
> additional current circuitry would add more noise.  See:
>
> http://www.linear.com/product/LTZ1000
>
>
> BillWB6BNQ
>
>
> Will Matney wrote:
>
>> Hello,
>>
>> I am in need of a very clean 24 Vdc power source, to replace some
>> old
>> mercury cell batteries with. What would a good low noise, clean,
> power
>> supply be in your recommendations? I thought of using two 12 Vdc
>> lead-acid
>> batteries in series, and making a charging circuit with regulators,
>

Re: [time-nuts] Low noise power supply recommendations

[Will Matney]

John,

I wondered about that, as using a LED is generally in conjunction with a
photo-transistor, and not a CDS cell. The reason I thought it might work is
that a company years back used them together to form a safety light
curtain.

The Fluke, and the HP, had a bad rep for those neon bulbs going out and
having to be replaced. I am going to replace the ones in the 844 before I
button it up, but was wondering if something else could be done. I looked
up the life cycle for the NE-3 and it's kind of low, especially compared to
a LED. I imagine the problem has to do with the brightness of the LED, as
compared to a neon bulb, when using a CDS cell.

As far as the power supply is concerned, I think I am going to go with
Ni-Cad batteries, and regulate the voltages. I think what they had was
nothing more than four step voltages from the battery supply, going from 3,
6 (7), 12, and 24 Vdc, or X2 of the other. From what I saw in the article
earlier, an easy zener with emotter follower regulator should do the trick
by the comparison with batteries. They used some resistance in series with
the zener to reduce noise, but it did decrease the stability somewhat. I
have seen this used in some old bias regulation circuits for tubes years
ago.

As far as the noise, I also wondered about this, as ESI used a current
limited DC power source to do the same thing, and it was ran off the AC
line.

Thanks,

Will

*** REPLY SEPARATOR  ***

On 6/14/2011 at 7:14 PM J. Forster wrote:

>The reason I asked is that most microvolt bridges use choppers and have BP
>filters at the chopper frequency, so noise is largely uncorrelated.
>
>On the neon photochoppers, it has been discussed at length several times
>on the HP-Agilent Yahyoo Group. A similar thing is used in the 410C. There
>are apparently issues with the CdS cells.
>
>Best,
>
>-John
>
>===
>
>
>> John,
>>
>> No, it's DC. I'm trying to meet the original specs of the batteries in
not
>> only voltage/current, but cleanliness of the current.
>>
>> Now inside the Fluke 844, it has a chopper, and it uses an AC power
supply
>> internally to feed its circuitry. The Vishays bridge uses the batteries
>> voltage, and one small AC power supply to run the digital portion of the
>> bridge for the PPM readout. The bridge itself is half analog and half
>> digital. The analog for the measurement, and the digital for the PPM
>> difference.
>>
>> By the way, has anyone ever converted a neon NE-3 driven chopper to
using
>> LED's? The bulbs have a sqaure wave coming into them of around 100-200
Hz
>> if I recall.
>>
>> Thanks,
>>
>> Will
>>
>> *** REPLY SEPARATOR  ***
>>
>> On 6/14/2011 at 6:50 PM J. Forster wrote:
>>
>>>Is the bridge excitation AC or DC. If it's AC, you may not even need
>>>low-noise power supplies.
>>>
>>>-John
>>>
>>>==
>>>
>>>
>>>
 Hi Will,

 You could consider building your own power supply system for the
 replacement of
 the batteries.  Use a separate power transformer which, I suspect,
 would
 be small
 as the current requirements would be low for driving a bridge circuit.

 The main company to look toward for high quality, low noise regulators
>> is
 Linear
 Technology.  Here is a candidate part to look at :
 http://www.linear.com/product/LT3082

 This is the lowest noise (33uv/10Hz to 100KHz) low dropout regulator
>> that
 can
 handle regulating 24 volts and is adjustable, meaning use can use this
 part for
 all three voltages (i.e., three regulators).  You will have to decide
 if
 it noise
 specs are suitable for your needs.  Keep in mind that battery noise is
 typically
 random whereas the noise out of a regulated system tends to be
 constant.

 If you really think you need lower noise then you could consider an
>> LT1000
 shunt
 reference.  Typically the circuit designs for LT1000 type devices are
 as
 references and lack current capability above about 10 milliamps.
 Adding
 additional current circuitry would add more noise.  See:

 http://www.linear.com/product/LTZ1000


 BillWB6BNQ


 Will Matney wrote:

> Hello,
>
> I am in need of a very clean 24 Vdc power source, to replace some old
> mercury cell batteries with. What would a good low noise, clean,
power
> supply be in your recommendations? I thought of using two 12 Vdc
> lead-acid
> batteries in series, and making a charging circuit with regulators,
> but
> I
> am hoping to purchase a good used supply off ebay, etc. The old
> circuit
> used two 12 Vdc snap terminal mercury batteries in series, for 24
Vdc,
> along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc
> batteries
> in series for 3 volts. Any help and or ideas would be appreciated.
>
> Thanks
>
> Will
>
> ___

Re: [time-nuts] Low noise power supply recommendations

[paul swed]

Though its a bit off topic
Ran into this chopper issue also on a HP410. I replaced the thing with a
modern chopper amp. I think an LTC. This was quite a few years ago (10 plus
easily) and it works very well. Still does actually. It did take a bit of
rework to get things back in balance correctly.

On Tue, Jun 14, 2011 at 10:14 PM, J. Forster  wrote:

> The reason I asked is that most microvolt bridges use choppers and have BP
> filters at the chopper frequency, so noise is largely uncorrelated.
>
> On the neon photochoppers, it has been discussed at length several times
> on the HP-Agilent Yahyoo Group. A similar thing is used in the 410C. There
> are apparently issues with the CdS cells.
>
> Best,
>
> -John
>
> ===
>
>
> > John,
> >
> > No, it's DC. I'm trying to meet the original specs of the batteries in
> not
> > only voltage/current, but cleanliness of the current.
> >
> > Now inside the Fluke 844, it has a chopper, and it uses an AC power
> supply
> > internally to feed its circuitry. The Vishays bridge uses the batteries
> > voltage, and one small AC power supply to run the digital portion of the
> > bridge for the PPM readout. The bridge itself is half analog and half
> > digital. The analog for the measurement, and the digital for the PPM
> > difference.
> >
> > By the way, has anyone ever converted a neon NE-3 driven chopper to using
> > LED's? The bulbs have a sqaure wave coming into them of around 100-200 Hz
> > if I recall.
> >
> > Thanks,
> >
> > Will
> >
> > *** REPLY SEPARATOR  ***
> >
> > On 6/14/2011 at 6:50 PM J. Forster wrote:
> >
> >>Is the bridge excitation AC or DC. If it's AC, you may not even need
> >>low-noise power supplies.
> >>
> >>-John
> >>
> >>==
> >>
> >>
> >>
> >>> Hi Will,
> >>>
> >>> You could consider building your own power supply system for the
> >>> replacement of
> >>> the batteries.  Use a separate power transformer which, I suspect,
> >>> would
> >>> be small
> >>> as the current requirements would be low for driving a bridge circuit.
> >>>
> >>> The main company to look toward for high quality, low noise regulators
> > is
> >>> Linear
> >>> Technology.  Here is a candidate part to look at :
> >>> http://www.linear.com/product/LT3082
> >>>
> >>> This is the lowest noise (33uv/10Hz to 100KHz) low dropout regulator
> > that
> >>> can
> >>> handle regulating 24 volts and is adjustable, meaning use can use this
> >>> part for
> >>> all three voltages (i.e., three regulators).  You will have to decide
> >>> if
> >>> it noise
> >>> specs are suitable for your needs.  Keep in mind that battery noise is
> >>> typically
> >>> random whereas the noise out of a regulated system tends to be
> >>> constant.
> >>>
> >>> If you really think you need lower noise then you could consider an
> > LT1000
> >>> shunt
> >>> reference.  Typically the circuit designs for LT1000 type devices are
> >>> as
> >>> references and lack current capability above about 10 milliamps.
> >>> Adding
> >>> additional current circuitry would add more noise.  See:
> >>>
> >>> http://www.linear.com/product/LTZ1000
> >>>
> >>>
> >>> BillWB6BNQ
> >>>
> >>>
> >>> Will Matney wrote:
> >>>
>  Hello,
> 
>  I am in need of a very clean 24 Vdc power source, to replace some old
>  mercury cell batteries with. What would a good low noise, clean, power
>  supply be in your recommendations? I thought of using two 12 Vdc
>  lead-acid
>  batteries in series, and making a charging circuit with regulators,
>  but
>  I
>  am hoping to purchase a good used supply off ebay, etc. The old
>  circuit
>  used two 12 Vdc snap terminal mercury batteries in series, for 24 Vdc,
>  along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc
>  batteries
>  in series for 3 volts. Any help and or ideas would be appreciated.
> 
>  Thanks
> 
>  Will
> 
>  ___
>  time-nuts mailing list -- time-nuts@febo.com
>  To unsubscribe, go to
>  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>  and follow the instructions there.
> >>>
> >>>
> >>> ___
> >>> time-nuts mailing list -- time-nuts@febo.com
> >>> To unsubscribe, go to
> >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >>> and follow the instructions there.
> >>>
> >>>
> >>
> >>
> >>
> >>___
> >>time-nuts mailing list -- time-nuts@febo.com
> >>To unsubscribe, go to
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >>and follow the instructions there.
> >>
> >>__ Information from ESET Smart Security, version of virus
> > signature database 5851 (20110206) __
> >>
> >>The message was checked by ESET Smart Security.
> >>
> >>http://www.eset.com
> >
> >
> >
> >
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
> > To un

Re: [time-nuts] Low noise power supply recommendations

[J. Forster]

I forgot to add that noise on the bridge excitation should not matter much
when the bridge is at null, as the differential mode voltage is zero.

-John

===


> John,
>
> No, it's DC. I'm trying to meet the original specs of the batteries in not
> only voltage/current, but cleanliness of the current.
>
> Now inside the Fluke 844, it has a chopper, and it uses an AC power supply
> internally to feed its circuitry. The Vishays bridge uses the batteries
> voltage, and one small AC power supply to run the digital portion of the
> bridge for the PPM readout. The bridge itself is half analog and half
> digital. The analog for the measurement, and the digital for the PPM
> difference.
>
> By the way, has anyone ever converted a neon NE-3 driven chopper to using
> LED's? The bulbs have a sqaure wave coming into them of around 100-200 Hz
> if I recall.
>
> Thanks,
>
> Will
>
> *** REPLY SEPARATOR  ***
>
> On 6/14/2011 at 6:50 PM J. Forster wrote:
>
>>Is the bridge excitation AC or DC. If it's AC, you may not even need
>>low-noise power supplies.
>>
>>-John
>>
>>==
>>
>>
>>
>>> Hi Will,
>>>
>>> You could consider building your own power supply system for the
>>> replacement of
>>> the batteries.  Use a separate power transformer which, I suspect,
>>> would
>>> be small
>>> as the current requirements would be low for driving a bridge circuit.
>>>
>>> The main company to look toward for high quality, low noise regulators
> is
>>> Linear
>>> Technology.  Here is a candidate part to look at :
>>> http://www.linear.com/product/LT3082
>>>
>>> This is the lowest noise (33uv/10Hz to 100KHz) low dropout regulator
> that
>>> can
>>> handle regulating 24 volts and is adjustable, meaning use can use this
>>> part for
>>> all three voltages (i.e., three regulators).  You will have to decide
>>> if
>>> it noise
>>> specs are suitable for your needs.  Keep in mind that battery noise is
>>> typically
>>> random whereas the noise out of a regulated system tends to be
>>> constant.
>>>
>>> If you really think you need lower noise then you could consider an
> LT1000
>>> shunt
>>> reference.  Typically the circuit designs for LT1000 type devices are
>>> as
>>> references and lack current capability above about 10 milliamps.
>>> Adding
>>> additional current circuitry would add more noise.  See:
>>>
>>> http://www.linear.com/product/LTZ1000
>>>
>>>
>>> BillWB6BNQ
>>>
>>>
>>> Will Matney wrote:
>>>
 Hello,

 I am in need of a very clean 24 Vdc power source, to replace some old
 mercury cell batteries with. What would a good low noise, clean, power
 supply be in your recommendations? I thought of using two 12 Vdc
 lead-acid
 batteries in series, and making a charging circuit with regulators,
 but
 I
 am hoping to purchase a good used supply off ebay, etc. The old
 circuit
 used two 12 Vdc snap terminal mercury batteries in series, for 24 Vdc,
 along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc
 batteries
 in series for 3 volts. Any help and or ideas would be appreciated.

 Thanks

 Will

 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.
>>>
>>>
>>> ___
>>> time-nuts mailing list -- time-nuts@febo.com
>>> To unsubscribe, go to
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>>>
>>
>>
>>
>>___
>>time-nuts mailing list -- time-nuts@febo.com
>>To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>and follow the instructions there.
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Re: [time-nuts] Low noise power supply recommendations

[J. Forster]

The reason I asked is that most microvolt bridges use choppers and have BP
filters at the chopper frequency, so noise is largely uncorrelated.

On the neon photochoppers, it has been discussed at length several times
on the HP-Agilent Yahyoo Group. A similar thing is used in the 410C. There
are apparently issues with the CdS cells.

Best,

-John

===


> John,
>
> No, it's DC. I'm trying to meet the original specs of the batteries in not
> only voltage/current, but cleanliness of the current.
>
> Now inside the Fluke 844, it has a chopper, and it uses an AC power supply
> internally to feed its circuitry. The Vishays bridge uses the batteries
> voltage, and one small AC power supply to run the digital portion of the
> bridge for the PPM readout. The bridge itself is half analog and half
> digital. The analog for the measurement, and the digital for the PPM
> difference.
>
> By the way, has anyone ever converted a neon NE-3 driven chopper to using
> LED's? The bulbs have a sqaure wave coming into them of around 100-200 Hz
> if I recall.
>
> Thanks,
>
> Will
>
> *** REPLY SEPARATOR  ***
>
> On 6/14/2011 at 6:50 PM J. Forster wrote:
>
>>Is the bridge excitation AC or DC. If it's AC, you may not even need
>>low-noise power supplies.
>>
>>-John
>>
>>==
>>
>>
>>
>>> Hi Will,
>>>
>>> You could consider building your own power supply system for the
>>> replacement of
>>> the batteries.  Use a separate power transformer which, I suspect,
>>> would
>>> be small
>>> as the current requirements would be low for driving a bridge circuit.
>>>
>>> The main company to look toward for high quality, low noise regulators
> is
>>> Linear
>>> Technology.  Here is a candidate part to look at :
>>> http://www.linear.com/product/LT3082
>>>
>>> This is the lowest noise (33uv/10Hz to 100KHz) low dropout regulator
> that
>>> can
>>> handle regulating 24 volts and is adjustable, meaning use can use this
>>> part for
>>> all three voltages (i.e., three regulators).  You will have to decide
>>> if
>>> it noise
>>> specs are suitable for your needs.  Keep in mind that battery noise is
>>> typically
>>> random whereas the noise out of a regulated system tends to be
>>> constant.
>>>
>>> If you really think you need lower noise then you could consider an
> LT1000
>>> shunt
>>> reference.  Typically the circuit designs for LT1000 type devices are
>>> as
>>> references and lack current capability above about 10 milliamps.
>>> Adding
>>> additional current circuitry would add more noise.  See:
>>>
>>> http://www.linear.com/product/LTZ1000
>>>
>>>
>>> BillWB6BNQ
>>>
>>>
>>> Will Matney wrote:
>>>
 Hello,

 I am in need of a very clean 24 Vdc power source, to replace some old
 mercury cell batteries with. What would a good low noise, clean, power
 supply be in your recommendations? I thought of using two 12 Vdc
 lead-acid
 batteries in series, and making a charging circuit with regulators,
 but
 I
 am hoping to purchase a good used supply off ebay, etc. The old
 circuit
 used two 12 Vdc snap terminal mercury batteries in series, for 24 Vdc,
 along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc
 batteries
 in series for 3 volts. Any help and or ideas would be appreciated.

 Thanks

 Will

 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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>>>
>>>
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>>
>>
>>
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Re: [time-nuts] Low noise power supply recommendations

[Will Matney]

John,

No, it's DC. I'm trying to meet the original specs of the batteries in not
only voltage/current, but cleanliness of the current.

Now inside the Fluke 844, it has a chopper, and it uses an AC power supply
internally to feed its circuitry. The Vishays bridge uses the batteries
voltage, and one small AC power supply to run the digital portion of the
bridge for the PPM readout. The bridge itself is half analog and half
digital. The analog for the measurement, and the digital for the PPM
difference.

By the way, has anyone ever converted a neon NE-3 driven chopper to using
LED's? The bulbs have a sqaure wave coming into them of around 100-200 Hz
if I recall.

Thanks,

Will

*** REPLY SEPARATOR  ***

On 6/14/2011 at 6:50 PM J. Forster wrote:

>Is the bridge excitation AC or DC. If it's AC, you may not even need
>low-noise power supplies.
>
>-John
>
>==
>
>
>
>> Hi Will,
>>
>> You could consider building your own power supply system for the
>> replacement of
>> the batteries.  Use a separate power transformer which, I suspect, would
>> be small
>> as the current requirements would be low for driving a bridge circuit.
>>
>> The main company to look toward for high quality, low noise regulators
is
>> Linear
>> Technology.  Here is a candidate part to look at :
>> http://www.linear.com/product/LT3082
>>
>> This is the lowest noise (33uv/10Hz to 100KHz) low dropout regulator
that
>> can
>> handle regulating 24 volts and is adjustable, meaning use can use this
>> part for
>> all three voltages (i.e., three regulators).  You will have to decide if
>> it noise
>> specs are suitable for your needs.  Keep in mind that battery noise is
>> typically
>> random whereas the noise out of a regulated system tends to be constant.
>>
>> If you really think you need lower noise then you could consider an
LT1000
>> shunt
>> reference.  Typically the circuit designs for LT1000 type devices are as
>> references and lack current capability above about 10 milliamps.  Adding
>> additional current circuitry would add more noise.  See:
>>
>> http://www.linear.com/product/LTZ1000
>>
>>
>> BillWB6BNQ
>>
>>
>> Will Matney wrote:
>>
>>> Hello,
>>>
>>> I am in need of a very clean 24 Vdc power source, to replace some old
>>> mercury cell batteries with. What would a good low noise, clean, power
>>> supply be in your recommendations? I thought of using two 12 Vdc
>>> lead-acid
>>> batteries in series, and making a charging circuit with regulators, but
>>> I
>>> am hoping to purchase a good used supply off ebay, etc. The old circuit
>>> used two 12 Vdc snap terminal mercury batteries in series, for 24 Vdc,
>>> along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc
>>> batteries
>>> in series for 3 volts. Any help and or ideas would be appreciated.
>>>
>>> Thanks
>>>
>>> Will
>>>
>>> ___
>>> time-nuts mailing list -- time-nuts@febo.com
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>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>
>>
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>
>
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Re: [time-nuts] Low noise power supply recommendations

[J. Forster]

Is the bridge excitation AC or DC. If it's AC, you may not even need
low-noise power supplies.

-John

==



> Hi Will,
>
> You could consider building your own power supply system for the
> replacement of
> the batteries.  Use a separate power transformer which, I suspect, would
> be small
> as the current requirements would be low for driving a bridge circuit.
>
> The main company to look toward for high quality, low noise regulators is
> Linear
> Technology.  Here is a candidate part to look at :
> http://www.linear.com/product/LT3082
>
> This is the lowest noise (33uv/10Hz to 100KHz) low dropout regulator that
> can
> handle regulating 24 volts and is adjustable, meaning use can use this
> part for
> all three voltages (i.e., three regulators).  You will have to decide if
> it noise
> specs are suitable for your needs.  Keep in mind that battery noise is
> typically
> random whereas the noise out of a regulated system tends to be constant.
>
> If you really think you need lower noise then you could consider an LT1000
> shunt
> reference.  Typically the circuit designs for LT1000 type devices are as
> references and lack current capability above about 10 milliamps.  Adding
> additional current circuitry would add more noise.  See:
>
> http://www.linear.com/product/LTZ1000
>
>
> BillWB6BNQ
>
>
> Will Matney wrote:
>
>> Hello,
>>
>> I am in need of a very clean 24 Vdc power source, to replace some old
>> mercury cell batteries with. What would a good low noise, clean, power
>> supply be in your recommendations? I thought of using two 12 Vdc
>> lead-acid
>> batteries in series, and making a charging circuit with regulators, but
>> I
>> am hoping to purchase a good used supply off ebay, etc. The old circuit
>> used two 12 Vdc snap terminal mercury batteries in series, for 24 Vdc,
>> along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc
>> batteries
>> in series for 3 volts. Any help and or ideas would be appreciated.
>>
>> Thanks
>>
>> Will
>>
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
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>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
>
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Re: [time-nuts] Low noise power supply recommendations

[Will Matney]

Bill,

I forgot to add, the Vishay bridge uses a Fluke 844 (OEM version of the
845AB) null-microvolt meter to read the bridge circuit. ESI did the same
thing, first using a HP 419, and then a Keithly 155 OEM meter assembly, for
their bridges.

The Fluke has its own supply from the line voltage. The batteries go to the
DC current supply for the bridge itself.

Thanks,

Will

*** REPLY SEPARATOR  ***

On 6/14/2011 at 6:13 PM WB6BNQ wrote:

>Hi Will,
>
>You could consider building your own power supply system for the
replacement of
>the batteries.  Use a separate power transformer which, I suspect, would
be small
>as the current requirements would be low for driving a bridge circuit.
>
>The main company to look toward for high quality, low noise regulators is
Linear
>Technology.  Here is a candidate part to look at :
>http://www.linear.com/product/LT3082
>
>This is the lowest noise (33uv/10Hz to 100KHz) low dropout regulator that
can
>handle regulating 24 volts and is adjustable, meaning use can use this
part for
>all three voltages (i.e., three regulators).  You will have to decide if
it noise
>specs are suitable for your needs.  Keep in mind that battery noise is
typically
>random whereas the noise out of a regulated system tends to be constant.
>
>If you really think you need lower noise then you could consider an LT1000
shunt
>reference.  Typically the circuit designs for LT1000 type devices are as
>references and lack current capability above about 10 milliamps.  Adding
>additional current circuitry would add more noise.  See:
>
>http://www.linear.com/product/LTZ1000
>
>
>BillWB6BNQ
>
>
>Will Matney wrote:
>
>> Hello,
>>
>> I am in need of a very clean 24 Vdc power source, to replace some old
>> mercury cell batteries with. What would a good low noise, clean, power
>> supply be in your recommendations? I thought of using two 12 Vdc
lead-acid
>> batteries in series, and making a charging circuit with regulators, but
I
>> am hoping to purchase a good used supply off ebay, etc. The old circuit
>> used two 12 Vdc snap terminal mercury batteries in series, for 24 Vdc,
>> along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc
batteries
>> in series for 3 volts. Any help and or ideas would be appreciated.
>>
>> Thanks
>>
>> Will
>>
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to
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>> and follow the instructions there.
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>
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Re: [time-nuts] Low noise power supply recommendations

[WB6BNQ]

Hi Will,

You could consider building your own power supply system for the replacement of
the batteries.  Use a separate power transformer which, I suspect, would be 
small
as the current requirements would be low for driving a bridge circuit.

The main company to look toward for high quality, low noise regulators is Linear
Technology.  Here is a candidate part to look at :
http://www.linear.com/product/LT3082

This is the lowest noise (33uv/10Hz to 100KHz) low dropout regulator that can
handle regulating 24 volts and is adjustable, meaning use can use this part for
all three voltages (i.e., three regulators).  You will have to decide if it 
noise
specs are suitable for your needs.  Keep in mind that battery noise is typically
random whereas the noise out of a regulated system tends to be constant.

If you really think you need lower noise then you could consider an LT1000 shunt
reference.  Typically the circuit designs for LT1000 type devices are as
references and lack current capability above about 10 milliamps.  Adding
additional current circuitry would add more noise.  See:

http://www.linear.com/product/LTZ1000


BillWB6BNQ


Will Matney wrote:

> Hello,
>
> I am in need of a very clean 24 Vdc power source, to replace some old
> mercury cell batteries with. What would a good low noise, clean, power
> supply be in your recommendations? I thought of using two 12 Vdc lead-acid
> batteries in series, and making a charging circuit with regulators, but I
> am hoping to purchase a good used supply off ebay, etc. The old circuit
> used two 12 Vdc snap terminal mercury batteries in series, for 24 Vdc,
> along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc batteries
> in series for 3 volts. Any help and or ideas would be appreciated.
>
> Thanks
>
> Will
>
> ___
> time-nuts mailing list -- time-nuts@febo.com
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Re: [time-nuts] Low noise power supply recommendations

[Will Matney]

Bob,

Yes, and especially after reading the article that Chris posted the link
to, I agree. Definately the lead-acid is out, after I saw the noise the
battery alone could generate. I always thought they were much cleaner than
that, and I wonder what type of havoc that could create on a GPS device in
a vehicle? Especially after the IC regulator circuits some use on top of
it. Since the ocxo should have a stable and clean rail voltage, after
seeing this, it makes one wonder.

What was so astounding was that a simple zener controlled series or shunt
regulator outpreformed plain battery circuits for noise, and blew away most
all IC type regulators. As a matter of fact, I remember these same similar
zener circuits used in citizens band base transceivers from my teens, and
wonder if they didn't know this then? After all, power source generated
noise can play havoc with the audio on any transceiver-receiver system, and
in precise measuring circuits too.

I think I will most likely use a Ni-Cad battery circuit, then use a version
of a zener controlled regulator, that was shown in the article, to obtain
all the battery voltages. I might try out a line operated power source
feeding it first, but I think the Ni-Cad would be better.

Thanks again,

Will

*** REPLY SEPARATOR  ***

On 6/14/2011 at 8:24 PM Bob Camp wrote:

>Hi
>
>Ni-cads are pretty low noise, reasonably stable, and close to the per cell
voltage of the mercury cells. The gotcha is the self discharge rate. If you
don't need a floating supply I suspect you can build up a " good enough"
linear regulator to get things working.
>
>Bob
>
>
>
>On Jun 14, 2011, at 8:12 PM, "Will Matney"  wrote:
>
>> Bob,
>> 
>> I've thought about that, and also thought about the 24 volt battery
packs
>> used in those Schwinn scooters the kids have. I can buy a 24 volt
charger
>> cheap for those, but the batteries run about $60.00 each plus shipping,
and
>> they are probably rated at around 4 amp hours, I think. It may be the
way I
>> go, since I think they are Ni-Cad instead of lead-acid. The problem is,
I
>> wonder what type of noise any voltage regulators will cause in the
circuit?
>> 
>> Thanks,
>> 
>> Will
>> 
>> *** REPLY SEPARATOR  ***
>> 
>> On 6/14/2011 at 8:01 PM Bob Camp wrote:
>> 
>>> Hi
>>> 
>>> Ni-cads are a pretty good bet.
>>> 
>>> Bob
>>> 
>>> 
>>> 
>>> On Jun 14, 2011, at 7:02 PM, "Will Matney"  wrote:
>>> 
 Hello,
 
 I am in need of a very clean 24 Vdc power source, to replace some old
 mercury cell batteries with. What would a good low noise, clean, power
 supply be in your recommendations? I thought of using two 12 Vdc
>> lead-acid
 batteries in series, and making a charging circuit with regulators,
but
>> I
 am hoping to purchase a good used supply off ebay, etc. The old
circuit
 used two 12 Vdc snap terminal mercury batteries in series, for 24 Vdc,
 along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc
>> batteries
 in series for 3 volts. Any help and or ideas would be appreciated.
 
 Thanks
 
 Will
 
 
 ___
 time-nuts mailing list -- time-nuts@febo.com
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>>> 
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>>> 
>>> http://www.eset.com
>> 
>> 
>> 
>> 
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Re: [time-nuts] Low noise power supply recommendations

[Bob Camp]

Hi

Ni-cads are pretty low noise, reasonably stable, and close to the per cell 
voltage of the mercury cells. The gotcha is the self discharge rate. If you 
don't need a floating supply I suspect you can build up a " good enough" linear 
regulator to get things working.

Bob



On Jun 14, 2011, at 8:12 PM, "Will Matney"  wrote:

> Bob,
> 
> I've thought about that, and also thought about the 24 volt battery packs
> used in those Schwinn scooters the kids have. I can buy a 24 volt charger
> cheap for those, but the batteries run about $60.00 each plus shipping, and
> they are probably rated at around 4 amp hours, I think. It may be the way I
> go, since I think they are Ni-Cad instead of lead-acid. The problem is, I
> wonder what type of noise any voltage regulators will cause in the circuit?
> 
> Thanks,
> 
> Will
> 
> *** REPLY SEPARATOR  ***
> 
> On 6/14/2011 at 8:01 PM Bob Camp wrote:
> 
>> Hi
>> 
>> Ni-cads are a pretty good bet.
>> 
>> Bob
>> 
>> 
>> 
>> On Jun 14, 2011, at 7:02 PM, "Will Matney"  wrote:
>> 
>>> Hello,
>>> 
>>> I am in need of a very clean 24 Vdc power source, to replace some old
>>> mercury cell batteries with. What would a good low noise, clean, power
>>> supply be in your recommendations? I thought of using two 12 Vdc
> lead-acid
>>> batteries in series, and making a charging circuit with regulators, but
> I
>>> am hoping to purchase a good used supply off ebay, etc. The old circuit
>>> used two 12 Vdc snap terminal mercury batteries in series, for 24 Vdc,
>>> along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc
> batteries
>>> in series for 3 volts. Any help and or ideas would be appreciated.
>>> 
>>> Thanks
>>> 
>>> Will
>>> 
>>> 
>>> ___
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> signature database 5851 (20110206) __
>> 
>> The message was checked by ESET Smart Security.
>> 
>> http://www.eset.com
> 
> 
> 
> 
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Re: [time-nuts] Low noise power supply recommendations

[Will Matney]

Bob,

I've thought about that, and also thought about the 24 volt battery packs
used in those Schwinn scooters the kids have. I can buy a 24 volt charger
cheap for those, but the batteries run about $60.00 each plus shipping, and
they are probably rated at around 4 amp hours, I think. It may be the way I
go, since I think they are Ni-Cad instead of lead-acid. The problem is, I
wonder what type of noise any voltage regulators will cause in the circuit?

Thanks,

Will

*** REPLY SEPARATOR  ***

On 6/14/2011 at 8:01 PM Bob Camp wrote:

>Hi
>
>Ni-cads are a pretty good bet.
>
>Bob
>
>
>
>On Jun 14, 2011, at 7:02 PM, "Will Matney"  wrote:
>
>> Hello,
>> 
>> I am in need of a very clean 24 Vdc power source, to replace some old
>> mercury cell batteries with. What would a good low noise, clean, power
>> supply be in your recommendations? I thought of using two 12 Vdc
lead-acid
>> batteries in series, and making a charging circuit with regulators, but
I
>> am hoping to purchase a good used supply off ebay, etc. The old circuit
>> used two 12 Vdc snap terminal mercury batteries in series, for 24 Vdc,
>> along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc
batteries
>> in series for 3 volts. Any help and or ideas would be appreciated.
>> 
>> Thanks
>> 
>> Will
>> 
>> 
>> ___
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Re: [time-nuts] Low noise power supply recommendations

[Will Matney]

Chirs,

No, actually, I need both. They used the mercury battery over its ability
to hold the voltage steady over its charged cycle, which was something they
did pretty well. It's a shame they've really not made anything to match
them yet, except I've heard of folks using Lithium in their place. I think
when they banned mercury cells, it helped with the slow death of Burgess
battery, since they produced a good majority of them.

The only battery supply that wouldn't have had good regulation, would have
been the 3 volt supply using the two AA batteries. The 7 volt, and the 24
volt both used the mercury types. Actually, I think they used 12 and 24 Vdc
off the two large mercuries, using the center tap for the 12 volt.

This is the supply for a very precise Vishay bridge measuring network. They
used a standard line power supply for everything but the supplies feeding
the bridge itself. The batteries gave a clean supply voltage, and the
mercury type batteries gave the regulation over standard carbon, etc..

I'll take a look at the link on the supplies, and thaks for that.

Thanks,

Will
*** REPLY SEPARATOR  ***

On 6/14/2011 at 4:46 PM Chris Albertson wrote:

>I was just looking at battery noise last week.   I assume you need low
>noise, not good regulation. If so then in practical terms, I think the
>best thing you could do is get an 8 cell battery holder for AA cells
>then connect a 220 uF capacitor across it.
>
>This is pretty good. has test results for several power supplies
>http://www.tnt-audio.com/clinica/regulators_noise1_e.html
>
>
>On Tue, Jun 14, 2011 at 4:02 PM, Will Matney  wrote:
>> Hello,
>>
>> I am in need of a very clean 24 Vdc power source, to replace some old
>> mercury cell batteries with. What would a good low noise, clean, power
>> supply be in your recommendations? I thought of using two 12 Vdc
lead-acid
>> batteries in series, and making a charging circuit with regulators, but
I
>> am hoping to purchase a good used supply off ebay, etc. The old circuit
>> used two 12 Vdc snap terminal mercury batteries in series, for 24 Vdc,
>> along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc
batteries
>> in series for 3 volts. Any help and or ideas would be appreciated.
>>
>> Thanks
>>
>> Will
>>
>>
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>
>
>
>-- 
>
>Chris Albertson
>Redondo Beach, California
>
>__ Information from ESET Smart Security, version of virus
signature database 5851 (20110206) __
>
>The message was checked by ESET Smart Security.
>
>http://www.eset.com




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Re: [time-nuts] Low noise power supply recommendations

[Bob Camp]

Hi

Ni-cads are a pretty good bet.

Bob



On Jun 14, 2011, at 7:02 PM, "Will Matney"  wrote:

> Hello,
> 
> I am in need of a very clean 24 Vdc power source, to replace some old
> mercury cell batteries with. What would a good low noise, clean, power
> supply be in your recommendations? I thought of using two 12 Vdc lead-acid
> batteries in series, and making a charging circuit with regulators, but I
> am hoping to purchase a good used supply off ebay, etc. The old circuit
> used two 12 Vdc snap terminal mercury batteries in series, for 24 Vdc,
> along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc batteries
> in series for 3 volts. Any help and or ideas would be appreciated.
> 
> Thanks
> 
> Will
> 
> 
> ___
> time-nuts mailing list -- time-nuts@febo.com
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Re: [time-nuts] Low noise power supply recommendations

[Chris Albertson]

I was just looking at battery noise last week.   I assume you need low
noise, not good regulation. If so then in practical terms, I think the
best thing you could do is get an 8 cell battery holder for AA cells
then connect a 220 uF capacitor across it.

This is pretty good. has test results for several power supplies
http://www.tnt-audio.com/clinica/regulators_noise1_e.html


On Tue, Jun 14, 2011 at 4:02 PM, Will Matney  wrote:
> Hello,
>
> I am in need of a very clean 24 Vdc power source, to replace some old
> mercury cell batteries with. What would a good low noise, clean, power
> supply be in your recommendations? I thought of using two 12 Vdc lead-acid
> batteries in series, and making a charging circuit with regulators, but I
> am hoping to purchase a good used supply off ebay, etc. The old circuit
> used two 12 Vdc snap terminal mercury batteries in series, for 24 Vdc,
> along with a 7 Vdc mercury cell, and two plain AA carbon 1.5 Vdc batteries
> in series for 3 volts. Any help and or ideas would be appreciated.
>
> Thanks
>
> Will
>
>
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



-- 

Chris Albertson
Redondo Beach, California

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Re: [time-nuts] Low noise power supply

[David VanHorn]

Granted my case wasn't a GPS app, and I didn't have sufficient test equipment 
to properly document the noise level of the final solution, but it made a huge 
improvement in picture quality relative to the SMPS alone, and I routinely 
design very quiet switchers. In this particular application, a linear only 
solution was not an option. The system ran on three 123A cells for about 20 
mins, with four of these imagers talking 27 MHz LVDS, a good sized FPGA, a fast 
processor running linux, high power Wifi, GPS receiver (antenova), and a suite 
of other sensors. The processor core alone ran six SMPSs.  Without good layout, 
the thing would have been an EMI nightmare.

The point of the 9000 was that it's CMRR is large, and I was able to put the 
SMPS feeding it in the "sweet spot" where the 9000 has best PSRR. That still 
requires high attention to current paths in layout but the result was very very 
good. Near starlight image capture where the factory recommended approach gave 
us nothing but noise at low light levels.




-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of ehydra
Sent: Wednesday, March 09, 2011 8:11 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Low noise power supply

For me, this looks like a advertisement campaign only. Not very 
sophisticated or ingenious. Read that you don't need LC-filters at the 
output because of the LDOs. *lol* If the designer ever heard of corner 
frequency??
And the ISL9000A is the same.


- Henry

-- 
ehydra.dyndns.info


David C. Partridge schrieb:
> H I wasn't impressed.  The 'scope screen shot of noise levels on the 
> outputs used 20mV/division, and the thickness of the regulated traces told us 
> precisely nothing.  Now if the author had measured 20uV noise over a BW of 
> 10Hz to 100kHz (about 63nV/rtHz), or 3uV over the same BW (about 10nV/rtHz), 
> I'd have started to get interested.  
> 
> However as no claims were made, I took the title of "Ultra-Low Noise" with a 
> large shovel of salt.   
> 
> 
> Regards,
> David Partridge
> 
> 
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On 
> Behalf Of ewkeh...@aol.com
> Sent: 08 March 2011 21:41
> To: time-nuts@febo.com
> Subject: [time-nuts] Low noise power supply
> 
> There is an interesting article in the March 2011 Electronic Products 
> magazine "design an ultra low noise supply for analog circuits. It is a 
> combination of switcher and LDO's and written by P Hunter TI so it may also  
> be available on their site.
> Bert Kehren
> ___
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Re: [time-nuts] Low noise power supply

[J. Forster]

Modern electronics, 1950s through maybe 2000 was all done on paper. The
magazines and books like the EEMs provide a very valuable reference for
specs on instruments and components.

When a company goes away, usually its web site does too. I'm certainly not
about to toss out my product literature files any time soon.

YMMV,

-John

===


> Hi John and group -
>
> For us germans, american magazines always look overloaded with
> advertisments. The marketenders don't like to hear that the generations
> under 40-50 are mostly advertisment blind just by natural adaption.
> The times where I read paper electronics are long gone. The Internet
> completely took over. Sometimes I go for wooden pdfs in the local
> university library.
>
> But back to the interesting subject - that I personally not fully
> resolved so there is a need of discussion!
> Here is a first insight:
> http://waltjung.org/PDFs/Sources_101_P2.pdf
>
> In general: LDO is bad. low Iq is bad too.
>
> cheers -
> Henry
>
>
> --
> ehydra.dyndns.info
>
>
> J. Forster schrieb:
>> Electronic Products is not a real engineering publication. It is a forum
>> purely for new product releases. Always has been.
>>
>> Articles there are almost always written by applications engineers for
>> the
>> product being touted.
>>
>> I got it free for decades, and threw the magazine away at once, unread.
>>
>> Why, you ask? Simple, the EEM...  Electronic Engineers' Master, the
>> giant,
>> multi-volume industry directory with company names and phone numbers,
>> about the size of a cinder block... came free, with a subscription.
>>
>> Best,
>>
>> -John
>
>



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Re: [time-nuts] Low noise power supply

[ehydra]

Hi John and group -

For us germans, american magazines always look overloaded with 
advertisments. The marketenders don't like to hear that the generations 
under 40-50 are mostly advertisment blind just by natural adaption.
The times where I read paper electronics are long gone. The Internet 
completely took over. Sometimes I go for wooden pdfs in the local 
university library.


But back to the interesting subject - that I personally not fully 
resolved so there is a need of discussion!

Here is a first insight:
http://waltjung.org/PDFs/Sources_101_P2.pdf

In general: LDO is bad. low Iq is bad too.

cheers -
Henry


--
ehydra.dyndns.info


J. Forster schrieb:

Electronic Products is not a real engineering publication. It is a forum
purely for new product releases. Always has been.

Articles there are almost always written by applications engineers for the
product being touted.

I got it free for decades, and threw the magazine away at once, unread.

Why, you ask? Simple, the EEM...  Electronic Engineers' Master, the giant,
multi-volume industry directory with company names and phone numbers,
about the size of a cinder block... came free, with a subscription.

Best,

-John



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Re: [time-nuts] Low noise power supply

[J. Forster]

Electronic Products is not a real engineering publication. It is a forum
purely for new product releases. Always has been.

Articles there are almost always written by applications engineers for the
product being touted.

I got it free for decades, and threw the magazine away at once, unread.

Why, you ask? Simple, the EEM...  Electronic Engineers' Master, the giant,
multi-volume industry directory with company names and phone numbers,
about the size of a cinder block... came free, with a subscription.

Best,

-John

=



> For me, this looks like a advertisement campaign only. Not very
> sophisticated or ingenious. Read that you don't need LC-filters at the
> output because of the LDOs. *lol* If the designer ever heard of corner
> frequency??
> And the ISL9000A is the same.
>
>
> - Henry
>
> --
> ehydra.dyndns.info
>
>
> David C. Partridge schrieb:
>> H I wasn't impressed.  The 'scope screen shot of noise levels on the
>> outputs used 20mV/division, and the thickness of the regulated traces
>> told us precisely nothing.  Now if the author had measured 20uV noise
>> over a BW of 10Hz to 100kHz (about 63nV/rtHz), or 3uV over the same BW
>> (about 10nV/rtHz), I'd have started to get interested.
>>
>> However as no claims were made, I took the title of "Ultra-Low Noise"
>> with a large shovel of salt.
>>
>>
>> Regards,
>> David Partridge
>>
>>
>> -Original Message-
>> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
>> Behalf Of ewkeh...@aol.com
>> Sent: 08 March 2011 21:41
>> To: time-nuts@febo.com
>> Subject: [time-nuts] Low noise power supply
>>
>> There is an interesting article in the March 2011 Electronic Products
>> magazine "design an ultra low noise supply for analog circuits. It is a
>> combination of switcher and LDO's and written by P Hunter TI so it may
>> also  be available on their site.
>> Bert Kehren
>> ___
>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>>
>> ___
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>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>
> ___
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> To unsubscribe, go to
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> and follow the instructions there.
>
>



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Re: [time-nuts] Low noise power supply

[ehydra]

For me, this looks like a advertisement campaign only. Not very 
sophisticated or ingenious. Read that you don't need LC-filters at the 
output because of the LDOs. *lol* If the designer ever heard of corner 
frequency??

And the ISL9000A is the same.


- Henry

--
ehydra.dyndns.info


David C. Partridge schrieb:
H I wasn't impressed.  The 'scope screen shot of noise levels on the outputs used 20mV/division, and the thickness of the regulated traces told us precisely nothing.  Now if the author had measured 20uV noise over a BW of 10Hz to 100kHz (about 63nV/rtHz), or 3uV over the same BW (about 10nV/rtHz), I'd have started to get interested.  

However as no claims were made, I took the title of "Ultra-Low Noise" with a large shovel of salt.   



Regards,
David Partridge


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of ewkeh...@aol.com
Sent: 08 March 2011 21:41
To: time-nuts@febo.com
Subject: [time-nuts] Low noise power supply

There is an interesting article in the March 2011 Electronic Products magazine 
"design an ultra low noise supply for analog circuits. It is a combination of 
switcher and LDO's and written by P Hunter TI so it may also  be available on their 
site.
Bert Kehren
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Re: [time-nuts] Low noise power supply

[ehydra]

If one can say that the actual noise-floor signal is approx. white noise 
than the peak to average is a factor of 6 to 7 on a analog scope. I once 
read this somewhere and found it not a so bad decision.



- Henry

--
ehydra.dyndns.info



David C. Partridge schrieb:
H I wasn't impressed.  The 'scope screen shot of noise levels on the outputs used 20mV/division, and the thickness of the regulated traces told us precisely nothing.  Now if the author had measured 20uV noise over a BW of 10Hz to 100kHz (about 63nV/rtHz), or 3uV over the same BW (about 10nV/rtHz), I'd have started to get interested.  

However as no claims were made, I took the title of "Ultra-Low Noise" with a large shovel of salt.   



Regards,
David Partridge


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Re: [time-nuts] Low noise power supply

[David C. Partridge]

H I wasn't impressed.  The 'scope screen shot of noise levels on the 
outputs used 20mV/division, and the thickness of the regulated traces told us 
precisely nothing.  Now if the author had measured 20uV noise over a BW of 10Hz 
to 100kHz (about 63nV/rtHz), or 3uV over the same BW (about 10nV/rtHz), I'd 
have started to get interested.  

However as no claims were made, I took the title of "Ultra-Low Noise" with a 
large shovel of salt.   


Regards,
David Partridge


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of ewkeh...@aol.com
Sent: 08 March 2011 21:41
To: time-nuts@febo.com
Subject: [time-nuts] Low noise power supply

There is an interesting article in the March 2011 Electronic Products magazine 
"design an ultra low noise supply for analog circuits. It is a combination of 
switcher and LDO's and written by P Hunter TI so it may also  be available on 
their site.
Bert Kehren
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Re: [time-nuts] Low noise power supply

[David VanHorn]

I used an ICL-9000 regulator 

ISL-9000. Sorry.

http://www.intersil.com/products/deviceinfo.asp?pn=ISL9000


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Re: [time-nuts] Low noise power supply

[David VanHorn]

I had this problem when using some ultra low light imagers.  They have NO PSRR, 
and the integration times were up in the 1-3 second range, so any noise on the 
pixel supply ended up in the image.

I used an ICL-9000 regulator which has ultra high PSRR, and I used a switcher 
running at a specific rate where the ICL-9000 has maximum PSRR.  I also was 
very concerned with waste power, so the SMPS was set up for the output to be 
just high enough for the linear to stay in regulation.  

For this app you'd want a beefier reg, but search for high PSRR at the right 
current range and work backward from there.

Layout is also HUGE in keeping switchers quiet.  Most of what I do has 
switchers in the 1-5W range, and I only use two layer boards, but I get my 
noise low enough that both the pre-scan with GTEM and OATS site can't see 
whether I'm on or off. (conducted or radiated thru 15 GHz)

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of ewkeh...@aol.com
Sent: Tuesday, March 08, 2011 2:41 PM
To: time-nuts@febo.com
Subject: [time-nuts] Low noise power supply

There is an interesting article in the March 2011 Electronic Products  
magazine "design an ultra low noise supply for analog circuits. It is a  
combination of switcher and LDO's and written by P Hunter TI so it may also  be 
available on their site.
Bert Kehren 
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Re: [time-nuts] Low noise power supply

[J. Forster]

This is not a "low noise" PS, IMO. There is far too much ripple on the
outputs for that.

Furthermore, I'd bet it has real radiated EMI issues.

-John

=


> At 16:41 -0500 08-03-2011, ewkeh...@aol.com wrote:
>>There is an interesting article in the March 2011 Electronic Products
>>magazine "design an ultra low noise supply for analog circuits. It is a
>>combination of switcher and LDO's and written by P Hunter TI so it
>>may also  be available on their site.
>
> This one, I presume:
> 
> ? Bit of a shame to use LDOs and then still drop 50% of the output
> voltage. Also, Fig 2 is meaningless without a measurement bandwidth
> spec.
>
> There are other ways to get a cleaner bipolar supply from a switcher,
> several of them simpler than what's shown here. You could take a
> SEPIC/Cuk hybrid, or pick a switcher that allows you to trade
> efficiency for switch slew rate like the LT1533. Some useful
> techniques are documented in .
>
> JDB.
> [not affiliated with Linear Tech other than being a satisfied customer]
> --
> Years from now, if you are doing something quick and dirty,
> you imagine that I am looking over your shoulder and say to
> yourself, "Dijkstra would not like this," well that would be
> immortality for me.  -- Edsger Dijkstra, 1930 - 2002
>
> ___
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>
>



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Re: [time-nuts] Low noise power supply

[ehydra]

Here:
http://www2.electronicproducts.com/Designing_an_ultra_low_noise_supply_for_analog_circuits-article-fapo_TI_mar2011-html.aspx

- Henry

--
ehydra.dyndns.info


ewkeh...@aol.com schrieb:
There is an interesting article in the March 2011 Electronic Products  
magazine "design an ultra low noise supply for analog circuits. It is a  
combination of switcher and LDO's and written by P Hunter TI so it may also  be 
available on their site.
Bert Kehren 


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Re: [time-nuts] Low noise power supply

[J.D. Bakker]

At 16:41 -0500 08-03-2011, ewkeh...@aol.com wrote:

There is an interesting article in the March 2011 Electronic Products
magazine "design an ultra low noise supply for analog circuits. It is a
combination of switcher and LDO's and written by P Hunter TI so it 
may also  be available on their site.


This one, I presume: 
 
? Bit of a shame to use LDOs and then still drop 50% of the output 
voltage. Also, Fig 2 is meaningless without a measurement bandwidth 
spec.


There are other ways to get a cleaner bipolar supply from a switcher, 
several of them simpler than what's shown here. You could take a 
SEPIC/Cuk hybrid, or pick a switcher that allows you to trade 
efficiency for switch slew rate like the LT1533. Some useful 
techniques are documented in .


JDB.
[not affiliated with Linear Tech other than being a satisfied customer]
--
Years from now, if you are doing something quick and dirty,
you imagine that I am looking over your shoulder and say to
yourself, "Dijkstra would not like this," well that would be
immortality for me.  -- Edsger Dijkstra, 1930 - 2002

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