temperature control circuit

[curtrw]

Hi, my name is Curt. I'm pretty much a novice at electronic circuit
building, having only built a couple of simple circuits. (555 timer)
My problem is I'm trying to build a 5-12volt dc circuit that will cool an
object (mirror) to ambient temperature via a fan, and then maintain that
temperature. Any referals or suggestions would be greatly appreciated.

Thanks in advance,
Curt

 

[John Larkin]

On Fri, 21 May 2004 13:48:25 -0500, "curtrw" <wellwan@autobahn.mb.ca>
wrote:

Hi, my name is Curt. I'm pretty much a novice at electronic circuit
building, having only built a couple of simple circuits. (555 timer)
My problem is I'm trying to build a 5-12volt dc circuit that will cool an
object (mirror) to ambient temperature via a fan, and then maintain that
temperature. Any referals or suggestions would be greatly appreciated.

Thanks in advance,
Curt

Isn't it impossible to cool something to ambient temp with a fan?

John

 

[mikem]

curtrw wrote:

Hi, my name is Curt. I'm pretty much a novice at electronic circuit
building, having only built a couple of simple circuits. (555 timer)
My problem is I'm trying to build a 5-12volt dc circuit that will cool an
object (mirror) to ambient temperature via a fan, and then maintain that
temperature. Any referals or suggestions would be greatly appreciated.

Thanks in advance,
Curt

Curt,

If there is something in/on the mirror that is dissipating
power, then adding a fan to blow air at the mirror might
lower the temperature of the mirror. This is because moving
air carries heat away from the mirror faster than just convection and/or
radiation would.

If the mirror is just passive (no power dissipation), then blowing air
at it will do nothing to change the temperature of the mirror, except to
reduce the thermal lag due to a sudden step change of temperature in the
ambient air.

If you truly want to "cool" it (reduce its temperature relative to
the ambient air), you need to plumb it to circulating cold water,
or bolt a Peltier device to it.

MikeM

 

[Spero Pefany]

On Fri, 21 May 2004 12:57:33 -0700, the renowned John Larkin
<jjlarkin@highSNIPlandTHIStechPLEASEnology.com> wrote:

On Fri, 21 May 2004 13:48:25 -0500, "curtrw" <wellwan@autobahn.mb.ca
wrote:

Hi, my name is Curt. I'm pretty much a novice at electronic circuit
building, having only built a couple of simple circuits. (555 timer)
My problem is I'm trying to build a 5-12volt dc circuit that will cool an
object (mirror) to ambient temperature via a fan, and then maintain that
temperature. Any referals or suggestions would be greatly appreciated.

Thanks in advance,
Curt


Isn't it impossible to cool something to ambient temp with a fan?
John

Assuming nothing is evaporating in said forced convection, yes. The
fan can only add heat. Either the OP doesn't know what "ambient
temperature" means or he's trying to do something impossible, neither
of which bodes well.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[John Larkin]

On Fri, 21 May 2004 21:44:01 GMT, Spero Pefany
<spffSNIP@interlogDOTyou.knowwhat> wrote:

On Fri, 21 May 2004 12:57:33 -0700, the renowned John Larkin
jjlarkin@highSNIPlandTHIStechPLEASEnology.com> wrote:

On Fri, 21 May 2004 13:48:25 -0500, "curtrw" <wellwan@autobahn.mb.ca
wrote:

Hi, my name is Curt. I'm pretty much a novice at electronic circuit
building, having only built a couple of simple circuits. (555 timer)
My problem is I'm trying to build a 5-12volt dc circuit that will cool an
object (mirror) to ambient temperature via a fan, and then maintain that
temperature. Any referals or suggestions would be greatly appreciated.

Thanks in advance,
Curt


Isn't it impossible to cool something to ambient temp with a fan?
John

Assuming nothing is evaporating in said forced convection, yes. The
fan can only add heat. Either the OP doesn't know what "ambient
temperature" means or he's trying to do something impossible, neither
of which bodes well.

Best regards,
Spehro Pefhany

No offense intended towards Curt, but there is in fact a branch of
mathematics devoted to "ill-posed problems" (a phrase that may be
googled to advantage), including my favorite, the deconvolution
problem.

We get a lot of ill-posed problems in s.e.d, mostly because the
posters don't want to (or maybe can't, for business reasons) explain
the entire context of what they want to do.

Hey, Curt, got more details?

John