[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
>>
>>
>> Bill....WB6BNQ
>>
>>
>> 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 at 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 at 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 at 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