Searching \ for '[EE]: crystal oven cct?' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/index.htm?key=crystal+oven+cct
Search entire site for: 'crystal oven cct?'.

Exact match. Not showing close matches.
PICList Thread
'[EE]: crystal oven cct?'
2001\09\28@182635 by Lawrence Glaister

flavicon
face
greetings,
I am building a 10mhz xtal frequency standard and am looking for a
circuit diagram for a simple temperature regulator. I have the
oscillator running in a small cast aluminum box and my idea was to bolt
a power transistor to the case and use that as the variable heating
element. I would then mount the whole unit inside a block of foam
insulation. I would like to hold the crystal at a non critical
temperature between 35-50C. Any ideas?
cheers
--

=====================================================================
Lawrence Glaister VE7IT              spam_OUTlgTakeThisOuTspamjfm.bc.ca
1462 Madrona Drive                   http://jfm.bc.ca/
Nanoose Bay, B.C.                    http://members.home.com/cncstuff
Canada          V9P 9C9              http://gspy.sourceforge.net
=====================================================================

--
http://www.piclist.com hint: To leave the PICList
.....piclist-unsubscribe-requestKILLspamspam@spam@mitvma.mit.edu


2001\09\28@190948 by Scott Newell

flavicon
face
>element. I would then mount the whole unit inside a block of foam
>insulation. I would like to hold the crystal at a non critical
>temperature between 35-50C. Any ideas?

The temperature is critical.  You want to hold it at the turning point of
the specific crystal where the Tc is zero.  Most common cheap AT cut rocks
are ground to have their turning point near room temperature.

I'd probably use a thermistor bridge circuit mounted in contact with the
heating device.

You might also read through:
       http://www.karlquist.com/osc.pdf


newell

--
http://www.piclist.com hint: To leave the PICList
piclist-unsubscribe-requestspamKILLspammitvma.mit.edu


2001\09\28@191203 by Andrew E. Kalman

flavicon
face
Re:

>I am building a 10mhz xtal frequency standard and am looking for a
>circuit diagram for a simple temperature regulator. I have the
>oscillator running in a small cast aluminum box and my idea was to bolt
>a power transistor to the case and use that as the variable heating
>element. I would then mount the whole unit inside a block of foam
>insulation. I would like to hold the crystal at a non critical
>temperature between 35-50C. Any ideas?


Don't know if the manuals are available on the web, but Stanford
Research Systems (http://www.srsys.com) includes schematics with all
their engineering products, and that would include the SR620 Time
Interval Counter, which has a TXCO option. You might get some ideas
from them ...
--

 ______________________________________
  Andrew E. Kalman, Ph.D.   .....aekKILLspamspam.....pumpkininc.com

--
http://www.piclist.com hint: To leave the PICList
EraseMEpiclist-unsubscribe-requestspam_OUTspamTakeThisOuTmitvma.mit.edu


2001\09\29@011736 by Mike Hardwick

flavicon
face
There's an interesting circuit in National's app note AN-460, page 8.
Here's a link to the PDF of AN-460:


http://www.national.com/an/AN/AN-460.pdf

Mike Hardwick
Decade Engineering


>I am building a 10mhz xtal frequency standard and am looking for a
>circuit diagram for a simple temperature regulator. I have the
>oscillator running in a small cast aluminum box and my idea was to bolt
>a power transistor to the case and use that as the variable heating
>element. I would then mount the whole unit inside a block of foam
>insulation. I would like to hold the crystal at a non critical
>temperature between 35-50C. Any ideas?

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\09\29@083655 by Peter L. Peres

picon face
There are several oven circuits in National and other catalogs. The
simplest oven is a single PTC thermistor made for this. It uses no
regulator, the characteristic is arranged such that it cuts off near 50C.
You can achieve 50C exactly by manipulating the heat loss from the oven
(cut or add insulation). A crystal used in an ovenized circuit is usually
optimized for operation at 50C. So perhaps aim for that temp. At 50C there
will be enough dissipation that you'll want to partially insulate the oven
(5 sides at least).

Peter

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads



'[EE]: crystal oven cct?'
2001\10\02@131249 by Norman Gillaspie
flavicon
face
There was an article in EDN Magazine. This months issue about using a
power fet for doing this and driving it with 5 volt logic and a
thermistor.

PCS Engineering
325 Sharon Park Dr. #210
Menlo Park, Ca 94070
Tel 650-854-5263
FAX 650-472-6436
Email normanspamspam_OUTpcseng.com
http://www.pcseng.com

"Your Connecting Link"


{Original Message removed}

2001\10\02@132714 by Mick Kent

flavicon
face
Digi-Key has a ESC inc. TCXO  page 419 of cat. T013
----- Original Message -----
From: "Norman Gillaspie" <@spam@normanKILLspamspamPCSENG.COM>
To: <KILLspamPICLISTKILLspamspamMITVMA.MIT.EDU>
Sent: Tuesday, October 02, 2001 12:11 PM
Subject: Re: [EE]: crystal oven cct?


| There was an article in EDN Magazine. This months issue about using a
| power fet for doing this and driving it with 5 volt logic and a
| thermistor.
|
| PCS Engineering
| 325 Sharon Park Dr. #210
| Menlo Park, Ca 94070
| Tel 650-854-5263
| FAX 650-472-6436
| Email RemoveMEnormanTakeThisOuTspampcseng.com
| http://www.pcseng.com
|
| "Your Connecting Link"
|
|
| {Original Message removed}

2001\10\02@145202 by Douglas Butler

flavicon
face
TCXO is a Temperature Compensated Xtal Oscillator, not quite as stable
as a crystal in an oven.  On the other hand a TCXO starts up quickly vs.
waiting for a chunk of aluminum to heat up and stabilize.

Sherpa Doug

> {Original Message removed}

2001\10\02@165338 by Bob Blick

face
flavicon
face
> > | greetings,
> > | I am building a 10mhz xtal frequency standard and am looking for a
> > | circuit diagram for a simple temperature regulator. I have the
> > | oscillator running in a small cast aluminum box and my idea
> > was to bolt
> > | a power transistor to the case and use that as the variable heating
> > | element. I would then mount the whole unit inside a block of foam
> > | insulation. I would like to hold the crystal at a non critical
> > | temperature between 35-50C. Any ideas?

Tjaart and I were talking about temperature controllers one day, and he
mentioned he made a crystal oven with a peltier device and bipolar
driver(driven by a PIC of course) that maintains 25 deg C. That way the
crystal aging is reduced, power consumption is low, and there's less
"warmup" time.

Another thing you might look at if you only need one and have connections
with old boat junk. Ancient Loran units had 10MHz references that were
highly accurate, and I've found ones with the reference in a tidy little
module.

Cheerful regards,

Bob

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email spamBeGonelistservspamBeGonespammitvma.mit.edu with SET PICList DIGEST in the body


2001\10\03@061136 by Alan B. Pearce

face picon face
>Tjaart and I were talking about temperature controllers one day, and he
>mentioned he made a crystal oven with a peltier device and bipolar
>driver(driven by a PIC of course) that maintains 25 deg C. That way the
>crystal aging is reduced, power consumption is low, and there's less
>"warmup" time.

That's cute. Does it work in reverse to cool the crystal when the exterior
temperature is above 25?

--
http://www.piclist.com hint: To leave the PICList
TakeThisOuTpiclist-unsubscribe-requestEraseMEspamspam_OUTmitvma.mit.edu


2001\10\03@085511 by cision Electronic Solutions

flavicon
face
Yes.  That's why he said bipolar driver - reversing the current reverses the
heat flow.

-----Original Message-----
From: pic microcontroller discussion list
[RemoveMEPICLISTspamTakeThisOuTMITVMA.MIT.EDU]On Behalf Of Alan B. Pearce
Sent: Wednesday, October 03, 2001 3:21 AM
To: PICLISTEraseMEspam.....MITVMA.MIT.EDU
Subject: Re: [EE]: crystal oven cct?


>Tjaart and I were talking about temperature controllers one day, and he
>mentioned he made a crystal oven with a peltier device and bipolar
>driver(driven by a PIC of course) that maintains 25 deg C. That way the
>crystal aging is reduced, power consumption is low, and there's less
>"warmup" time.

That's cute. Does it work in reverse to cool the crystal when the exterior
temperature is above 25?

--
http://www.piclist.com hint: To leave the PICList
EraseMEpiclist-unsubscribe-requestspammitvma.mit.edu

--
http://www.piclist.com hint: To leave the PICList
RemoveMEpiclist-unsubscribe-requestEraseMEspamEraseMEmitvma.mit.edu


2001\10\03@143930 by Harold M Hallikainen

picon face
       I recall seeing a self regulating thermistor based crystal heater years
ago. It might have been from murata or CTS. It was a PTC thermistor with
a clip that clipped it onto the crystal case. Apply a DC voltage and it
heats up to a specified temperature. Put the whole thing in an insulated
can to reduce power dissipation.
       Another trick is to use the LM399H voltage reference as a termperature
controlled heater. I don't know if the temperature is the best for the
crystal (at the lowest tempco point), but the LM399H has a built-in
heater and temperature controller so its voltage reference doesn't have
to deal with varying temperature. I think you could cut the insulating
case off the LM399H, glue it to the crystal case (or solder it?), then
put the whole thing in an insulated case. Should hold the crystal
temperature pretty stable.
       On crystal ovens... back when I worked in broadcast stations, we had a
950 MHz Studio to Transmitter Link that used a thermostat based crystal
oven. One day the FM station dropped off the air. A trip to the site
showed that the remote transmitter control had lost the 110 kHz control
subcarrier off the STL. A look at the discriminator voltage showed
SOMETHING was way off frequency (either the transmitter or the receiver),
possibly causing the subcarrier to go outside the IF passband. Back to
the STL transmitter site. Found the thermostat on the crystal oven had
stuck, heating the crystal enough to knock the transmitter way off
frequency. Disabled the oven until a replacement was received (this was
one of those little octal based things that held two crystals). All was
well...

Harold


On Fri, 28 Sep 2001 18:08:14 -0500 Scott Newell <RemoveMEnewellspam_OUTspamKILLspamCEI.NET> writes:
{Quote hidden}

FCC Rules Online at http://hallikainen.com/FccRules
Lighting control for theatre and television at http://www.dovesystems.com

________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today!  For your FREE software, visit:
dl.http://www.juno.com/get/web/.

--
http://www.piclist.com hint: To leave the PICList
EraseMEpiclist-unsubscribe-requestspamspamspamBeGonemitvma.mit.edu


2001\10\03@164844 by Jim

flavicon
face
   "I recall seeing a self regulating
    thermistor based crystal heater
    years ago. It might have been from
    murata or CTS. It was a PTC thermistor
    with a clip that clipped it onto the
    crystal case. Apply a DC voltage ..."

Crude, but will work with the PTC thermistor
soldered to the xtal can ... had a VHF Engineering
Synthesizer II (144-148 MHz range with a 10.24 MHz
reference xtal osc) so equipped to ward of drift
seen during cold Michigan winters in the late
70's ... drifts of greater than 4 KHz (at channel
frequency or F-sub-o) were being experienced w/o
the PTC being added ...

As it turned out half of the drift was actually due
to the TTL INVERTER used as the 'active' element in
that xtal osc circuit - a single bipolar transistor
eliminated the amount of 'time delay' versus
temperature and the xtal circuit 'oscillated' 5 KHz
higher in frequency with the single transistor design
versus the TTL gate ... a new xtal was required
since an xtal at 10.24 MHz can't be 'pulled' quite
that far ...

I went through numerous cold-soaks in the freezer and
even several hot-cycles in a full size oven evaluating
each change ...

Jim


{Original Message removed}

2001\10\03@193833 by Mike Hardwick

flavicon
face
Thermal control hardware can be simplified if you have a micro in the
system... Use a DS18S20 or similar temp sensor (takes one I/O pin) and a
software-controlled heater (one more I/O pin). The heater can be a cheap
power transistor in a constant-current circuit (with another small
transistor). With some attention in software to thermal delay, etc., you
can get excellent results with this approach. A PWM generator can
"linearize" heater response...

Mike Hardwick, for Decade Engineering -- <http://www.decadenet.com>
Manufacturer of the famous BOB-II Serial Video Text Display Module!

--
http://www.piclist.com hint: To leave the PICList
RemoveMEpiclist-unsubscribe-requestKILLspamspammitvma.mit.edu


2001\10\04@013551 by norman

flavicon
face
The article was in EDN magazine september 17, 2001 and is available online.

Titled SOT-223 High-Voltage Transistor Creates LCD Heater


Norman

Norman Gillaspie
PCS Engineering
325 Sharon Park Dr. #210
Menlo Park, Ca 94025
Tel(650)854-5263
Fax(650)472-6436
Email normanSTOPspamspamspam_OUTpcseng.com
Digital QAM QPSK 8PSK 8VSB MPEG DVB Modulators and RF Converters
"PCS Your Connecting Link"
http://www.pcseng.com
KF6WMG


{Original Message removed}

2001\10\04@090737 by Olin Lathrop

face picon face
> Thermal control hardware can be simplified if you have a micro in the
> system... Use a DS18S20 or similar temp sensor (takes one I/O pin) and a
> software-controlled heater (one more I/O pin). The heater can be a cheap
> power transistor in a constant-current circuit (with another small
> transistor). With some attention in software to thermal delay, etc., you
> can get excellent results with this approach. A PWM generator can
> "linearize" heater response...

If you are just trying to hold a preset temperature, then you don't need a
linear temperature sensor.  It only needs to be monotonic.


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, spamBeGoneolinSTOPspamspamEraseMEembedinc.com, http://www.embedinc.com

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\10\04@124204 by Harold M Hallikainen

picon face
On Thu, 4 Oct 2001 07:12:21 -0400 Olin Lathrop
<KILLspamolin_piclistspamBeGonespamEMBEDINC.COM> writes:
>
> If you are just trying to hold a preset temperature, then you don't
> need a
> linear temperature sensor.  It only needs to be monotonic.
>

       True, but... nonlinearity (at least major nonlinearity) shows up as a
variation in loop gain which can affect droop and stability of the
temperature control circuit.

Harold

FCC Rules Online at http://hallikainen.com/FccRules
Lighting control for theatre and television at http://www.dovesystems.com

________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today!  For your FREE software, visit:
dl.http://www.juno.com/get/web/.

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\10\05@060747 by Vasile Surducan

flavicon
face
I have do it a couple a years ago with only one 723 in to99 package which
is the heater and the controller of the crystal temperature, but it's
working only for small crystals and with a good stability near 50...60 C.
Note that's for a wrong cut of the crystal the stability is worse at
60C than without thermal compensation at 25 C

Vasile

On Wed, 3 Oct 2001, Mike Hardwick wrote:

{Quote hidden}

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


More... (looser matching)
- Last day of these posts
- In 2001 , 2002 only
- Today
- New search...