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Bruce Griffiths wrote:
Don Collie wrote:
I`ve always wondered about noise from batteries - please tell us more
Bruce!! [also wondered about noise from the electrolytic action of
aluminium, and tantalum
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From: Tom Clifton [EMAIL PROTECTED]
Subject: Re: [time-nuts] Parallel voltage regulators
Date: Fri, 26 Oct 2007 17:19:45 -0700 (PDT)
Message-ID: [EMAIL PROTECTED]
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There is a concept in temperature control called feed-forward.
In this case you would sample the supply line with an inverting
amplifier and use it to increase the oven drive signal as the
line voltage decreases. The goal is
time-nuts@febo.com
Sent: Friday, October 26, 2007 12:29 PM
Subject: Re: [time-nuts] Parallel voltage regulators
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The simple answer is if the heater supply in unregulated, and the
supply changes, it will take a little while
voltage regulators
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Magnus Danielson wrote:
From: Bruce Griffiths [EMAIL PROTECTED]
Subject: Re: [time-nuts] Parallel voltage regulators
Date: Thu, 25 Oct 2007 17:42:51 +1300
Message-ID: [EMAIL PROTECTED]
Don Collie wrote
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Don Collie wrote:
Bruce
I don`t think the higher current created when a fuse is used instead of
near-instantaneous current limiting is alleged, but rather a real problem
that can cause damage further down the line. Fast
Subject: Re: [time-nuts] Parallel voltage regulators
There is a concept in temperature control called feed-forward.
In this case you would sample the supply line with an inverting
amplifier and use it to increase the oven drive signal as the
line voltage decreases. The goal is to keep
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Considering the efficiency and easy availability of switchmode
supplies these days, I would never bother with a linear regulator
in a new design.
For instance national has a series of switch mode regulators (LM25xx)
which
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Poul-Henning Kamp wrote:
Considering the efficiency and easy availability of switchmode
supplies these days, I would never bother with a linear regulator
in a new design.
For instance national has a series of switch mode
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Poul-Henning Kamp wrote:
Considering the efficiency and easy availability of switchmode
supplies these days, I would never bother with a linear regulator
in a new design.
For instance national has a series of switch
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Switchmode regulators really are risky for use in a low
noise environment. Even if you can reduce input and
output conducted noise to acceptable levels, the
opportunity for magnetic coupling from the inductor
to adjacent
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Pete wrote:
Switchmode regulators really are risky for use in a low
noise environment. Even if you can reduce input and
output conducted noise to acceptable levels, the
opportunity for magnetic coupling from the inductor
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J.D. Bakker wrote:
Poul-Henning Kamp wrote:
Considering the efficiency and easy availability of switchmode
supplies these days, I would never bother with a linear regulator
in a new design.
For instance national
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In a message dated 10/26/2007 14:59:29 Pacific Daylight Time,
[EMAIL PROTECTED] writes:
That is a recipe for disaster if one wants a really low noise oscillator.
This is particularly true if one is a beginner.
27, 2007 10:07 AM
Subject: Re: [time-nuts] Parallel voltage regulators
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I do have some experience with temperature controlled ovens. I found that
a
long term plot of the temperature while using an unregulated supply
: Re: [time-nuts] Parallel voltage regulators
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I do have some experience with temperature controlled ovens. I found
that a long term plot of the temperature while using an unregulated
supply on the oven heater showed small
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This has been a fascinating and educational thread! I
have always been aware of noise coming from switching
regulators - just have Argo or Speclab look at your
laptop's sound card with no input signal and there
is plenty to
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Tom Clifton wrote:
This has been a fascinating and educational thread! I
have always been aware of noise coming from switching
regulators - just have Argo or Speclab look at your
laptop's sound card with no input signal
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Don Collie wrote:
Great idea!!,Don C.
Now all you need is a current limited bypass switch to protect the load.
Such a switch is relatively easy to implement.
Bruce
] Parallel voltage regulators
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Tom Clifton wrote:
This has been a fascinating and educational thread! I
have always been aware of noise coming from switching
regulators - just have Argo or Speclab look at your
laptop's
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Don Collie wrote:
I`ve always wondered about noise from batteries - please tell us more
Bruce!! [also wondered about noise from the electrolytic action of
aluminium, and tantalum electrolytic capacitors, and wondered
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Don Collie wrote:
I`ve always wondered about noise from batteries - please tell us more
Bruce!! [also wondered about noise from the electrolytic action of
aluminium, and tantalum electrolytic capacitors, and wondered
of precise time and
frequency measurement time-nuts@febo.com
Sent: Thursday, October 25, 2007 5:42 PM
Subject: Re: [time-nuts] Parallel voltage regulators
Show me where that is actually guaranteed on the datasheet.
Only the inexperienced and the gullible fall into the trap of assuming
every
: Re: [time-nuts] Parallel voltage regulators
Don Collie wrote:
Bollocs, Bruce! If National say it will do it, you can bet that it will.
An
LM338K will do the job too, but in my opinion it`s overkill, and in the
event of a short circuit on the output of the regulator the current
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Don Collie wrote:
Hi Bruce,
I`ve got the National Semiconductor Corporation Voltage Regulator
Handbook [1982]. On page 3-3, the leftmost graph shows the LM117/217/317 as
having its current limit, with a junction
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From: Bruce Griffiths [EMAIL PROTECTED]
Subject: Re: [time-nuts] Parallel voltage regulators
Date: Thu, 25 Oct 2007 13:51:47 +1300
Message-ID: [EMAIL PROTECTED]
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Magnus Danielson wrote:
From: Bruce Griffiths [EMAIL PROTECTED]
Subject: Re: [time-nuts] Parallel voltage regulators
Date: Thu, 25 Oct 2007 17:42:51 +1300
Message-ID: [EMAIL PROTECTED]
Don Collie wrote:
Hi Tom
: [time-nuts] Parallel voltage regulators
A question for those that might know (or have an
opinion)... I have in hand an LPRO rubidium reference
that requires 1.7 amps at 24 volts while the oven
warms, dropping to 500ma while it runs.
Can I parallel three or four 7824 TO220 style 1 amp
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Alan Melia wrote:
Hi Tom I dont think you need the resistors these are current limited and the
sense is inside the chip so the resistors dont do anything (you are thinking
of a negative feedback effect). All that happens in
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Magnus Danielson wrote:
It is not that hard to acheive 2 A at 24 V after all. The old uA723 and
variants would probably do the trick good enought for you with external
transitor(s).
I recommend to at least include
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Tom C,
As Bruce notes below, the LM338K is a 5 amp job with a 35v max DC input
rating.
Just allow adequate heatsinking otherwise the 338 will foldback due to
over temperature.
There's plenty of on-line help to select the
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Tom Clifton [EMAIL PROTECTED] wrote:
A question for those that might know (or have an
opinion)... I have in hand an LPRO rubidium reference
that requires 1.7 amps at 24 volts while the oven
warms, dropping to 500ma while
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Thanks for all the good feedback! Looks like the LM388
is the way I'm to go. Got to toddle off to the local
surplus shop in the morning to see what they have in
the goodie bin. If they don't have it eBay is full of
them.
Tom
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christopher hoover wrote:
Tom,
Most of the oven circuits will tolerate a significant sag in potential
during warm-up as long as the supply doesn't cut out. I've often run OCXO's
and Rb's off a wimpy bench supply when my
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Hi Tom:
When I had that problem a work around was to parallel a battery with the power
supply (using a diode). The battery supplies the extra current while the oven
warms up. If the power supply voltage is a little higher
. A single one
of these should do the job OK.
Cheers!,.Don Collie jnr.
- Original Message -
From: Tom Clifton [EMAIL PROTECTED]
To: time-nuts@febo.com
Sent: Thursday, October 25, 2007 12:33 PM
Subject: [time-nuts] Parallel voltage regulators
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Don Collie wrote:
Hi Tom,
If you really want to regulate the oven`s supply voltage, my National
Voltage Regulator handbook shows that the LM317T will supply over 2 Amps,
with an input/output differential of between 5,
time-nuts@febo.com
Sent: Thursday, October 25, 2007 5:42 PM
Subject: Re: [time-nuts] Parallel voltage regulators
Don Collie wrote:
Hi Tom,
If you really want to regulate the oven`s supply voltage, my National
Voltage Regulator handbook shows that the LM317T will supply over 2 Amps
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