[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" <xformer at citynet.net> 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" <xformer at citynet.net> 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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