 |
Search Sci.Electronics.Basics |
|
|
|
|
|
|
 |
|
|
Sci.Electronics.Basics -> what type of probe is this? e.g. K-Type e.t.c.
There are 27 messages in this thread.
You are currently looking at messages 1 to 20.
|
Author: jameshanley39@yahoo.co.ukDate: 21:53 21-05-08
|
|
I would like to get a temperature probe like this, from an electronics
place.
How would it be described technically? I know they have specific
names, for the form of the bit at the end. K-Type e.t.c.
Here is a picture (it is measuring a HDD temp)
http://www.overclockersclub.com/reviews/nzxt_sentry/images/12.htm
I am also interested in the same question, regarding this probe.
It is measuring CPU temp
http://www.overclockersclub.com/reviews/nzxt_sentry/images/9.htm
Note- I know there are other ways. Software, IR Temp sensor Gun, to
measure temp of components. But I am interested particularly, in these
temp probes like in the picture. some wires and a thing on the end,
and you tape it to the component and read the temperature.
Thanks.
|
|
|
|
Author: BobGDate: 22:23 21-05-08
|
|
You dont need a Type K thermocouple until you get in the 100s of
degrees... like for exhaust temperature but a max6675 thermocouple
preamp lets you read 0-1023 deg c on an SPI interface. An IC like an
LM35 puts out 10mv per degree C, has 3 wires, read with an a/d input.
A maxim DS18B20 reads 16th degrees C on a 2 wire digital bus. There
are Positive Temperature Coefficient and Negative TC thermistors that
are accurate but nonlinear and need the correct bias resistor to
prevent self heating. Read with a/d input. Phew. Lots of choices.
|
|
|
|
Author: jameshanley39@yahoo.co.ukDate: 22:47 21-05-08
|
|
On 22 May, 03:23, BobG <bobgard...@aol.com> wrote:
> You dont need a Type K thermocouple until you get in the 100s of
> degrees... like for exhaust temperature but a max6675 thermocouple
> preamp lets you read 0-1023 deg c on an SPI interface. An IC like an
> LM35 puts out 10mv per degree C, has 3 wires, read with an a/d input.
> A maxim DS18B20 reads 16th degrees C on a 2 wire digital bus. There
> are Positive Temperature Coefficient and Negative TC thermistors that
> are accurate but nonlinear and need the correct bias resistor to
> prevent self heating. Read with a/d input. Phew. Lots of choices.
Forget I said K-Type Thermoprobe
What is the type of probe that is in that picture, measuring the
temperature of that hard drive?
(As in physically. And as far as temp sensing range is concerned, I
am interested in 0-100C)
|
|
|
|
Author: Phil AllisonDate: 22:51 21-05-08
|
|
"BobG" <
> You dont need a Type K thermocouple until you get in the 100s of
> degrees...
** Not true.
K-type thermocouples are ideal for many applications over a very wide temp
range - mainly due to the tiny thermal mass and size of the bead that has
to be heated (or cooled).
Perfect for small semiconductors, heatsinks and inaccessible spots.
In any case, most K probes are sold with Teflon coated lead wires and so are
only safe up to 250 C max.
.... Phil
|
|
|
|
Author: Phil AllisonDate: 22:54 21-05-08
|
|
<jameshanley39@yahoo.co.uk
>
> Forget I said K-Type Thermoprobe
>
> What is the type of probe that is in that picture, measuring the
> temperature of that hard drive?
>
** Impossible to tell - that pic is far from clear enough and there is
nothing distinctive about what you can see.
My bet is that it is a simple thermistor or maybe just a diode & not a
"thermocouple" at all.
..... Phil
|
|
|
|
Author: jameshanley39@yahoo.co.ukDate: 01:45 22-05-08
|
|
On 22 May, 03:54, "Phil Allison" <philalli...@tpg.com.au> wrote:
> <jameshanle...@yahoo.co.uk
>
>
>
> > Forget I said K-Type Thermoprobe
>
> > What is the type of probe =A0that is in that picture, measuring the
> > temperature of that hard drive?
>
> ** Impossible to tell =A0- =A0that pic is far from clear enough and there =
is
> nothing distinctive about what you can see.
>
> My bet is that it is a simple thermistor or maybe just a diode & not a
> "thermocouple" =A0at all.
>
> ..... =A0Phil
ok..
note- that word thermocouple only slipped accidentally. BobG
mentioned it, and it stuck in my head when writing my post!
I guess the name for the type of ending that probe has, is unknown..
And maybe it isn't even that significant. Maybe a bead type ending
would be fine.
I spoke to a brilliant electronics guy.. he couldn't give me a name
for the shape of the thing at the end of it. I guess a flat U
shape! looks better contact than a bead.
He mentioned to me that a
Thermistor - measures resistance
Thermocouple - measures voltage
and they have tables that show resistance or voltage. compared to
temperature.
It can do 0-100C
I have a bead thermister somewhere.
http://www.maplin.co.uk/module.aspx?ITAG=3DSPEC&ModuleNo=3D2218&doy=3D14m2#s=
pec
maplin number FX21 i think
Apparently, it's non-linear (NTC my electronics friend said) So I
won't bother trying to plot it on a graph myself(like with hot water
and ice). I will use a table/graph it comes with.. The maplin guy sent
me a pdf with that data.
Apparently there are devices with LED screens and wires to a
thermistor.
Digital Multimeters with a bead thermister, or one that plugs in.
Though that is effectively the same.
Though the devices with LED screens and wires to a thermister, would
probably have a chip to convert it to Degrees C.
Since I am measuring temp of a hdd in an enclosure,
I asked my electronics friend (I talked to in a chat - on IRC ) I
asked him if a long wire would cause any problem..
The electronics guy said it was fine and was sure that even a 30cm
thin wire would cause a negligible resistance difference compared to
the error within the thermistor itself. I said wire would be as thin
as the wire that connects PC Speaker to connector to jumper within
computer. He said that's 24AWG he reckoned.
I seem to remember crocodile clips getting bad contact.. And I recall
different contact between wire and legs of thermistor, causing
different resistance.
He said that croc clips would be fine though
Though I will be using < 30cm thin wires.. He confirmed my suggestion
that it's fine to wind them round the legs. and tape them with
insulation tape
So. I guess i'll look back into this..
But may get that device anyway.. then I can test my thermistor usage
skills!
Will test it with a thermometer in water compared to "my thermistor"
in water too.
|
|
|
|
Author: EeyoreDate: 05:01 22-05-08
|
|
Phil Allison wrote:
> "BobG" <
>
> > You dont need a Type K thermocouple until you get in the 100s of
> > degrees...
>
> ** Not true.
>
> K-type thermocouples are ideal for many applications over a very wide temp
> range - mainly due to the tiny thermal mass and size of the bead that has
> to be heated (or cooled).
>
> Perfect for small semiconductors, heatsinks and inaccessible spots.
>
> In any case, most K probes are sold with Teflon coated lead wires and so are
> only safe up to 250 C max.
I agree 100%.
Furthermore, there are many quite inexpensive DMMs with K-type inputs. A K-type
thermocouple is the simplest to use for the non-expert who doesn't want to get
involved in all the fuss with different themocouple materials.
One small point. K-type connectors used to be colour coded yellow. It seems to
have changed to green now for some daft reason. They are compatible though.
Graham
|
|
|
|
Author: jameshanley39@yahoo.co.ukDate: 08:22 22-05-08
|
|
On 22 May, 10:01, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:
> Phil Allison wrote:
> > "BobG" <
>
> > > You dont need a Type K thermocouple until you get in the 100s of
> > > degrees...
>
> > ** Not true.
>
> > K-type thermocouples are ideal for many applications over a very wide te=
mp
> > range =A0- =A0mainly due to the tiny thermal mass and size of the bead t=
hat has
> > to be heated (or cooled).
>
> > Perfect for small semiconductors, heatsinks and inaccessible spots.
>
> > In any case, most K probes are sold with Teflon coated lead wires and so=
are
> > only safe up to 250 C max.
>
> I agree 100%.
>
> Furthermore, there are many quite inexpensive DMMs with K-type inputs. A K=
-type
> thermocouple is the simplest to use for the non-expert who doesn't want to=
get
> involved in all the fuss with different themocouple materials.
>
> One small point. K-type connectors used to be colour coded yellow. It seem=
s to
> have changed to green now for some daft reason. They are compatible though=
.
>
> Graham-
I see, K-Type refers to the power end, not the sensing end , which was
what I was wondering about.
I will get a DMM with a K-Type socket .. And a K-Type thermistor to
match.
Regarding material for the thermocouple. My friend did mention that a
thermocouple uses 2 different metals, to get a difference in voltage.
But a)I will be using a thermistor anyway b)I just ask the electronics
store for one that goes 0-100C , and a table. That's the
functionality, so the implemenetation - if there are differences ,
makes no difference to me.
If for example I don't get a K-Type plug DMM and K-Type Thermistor.
Are there then any issues with wrapping wire around the legs of a bead
thermistor, tying them to it with insulation tape, and connecting them
to a DMM with crocodile clips?
Thanks
|
|
|
|
Author: Phil AllisonDate: 08:55 22-05-08
|
|
<jameshanley39@yahoo.co.uk>
I see, K-Type refers to the power end, not the sensing end , which was
what I was wondering about.
I will get a DMM with a K-Type socket .. And a K-Type thermistor to
match.
Regarding material for the thermocouple. My friend did mention that a
thermocouple uses 2 different metals, to get a difference in voltage.
But a)I will be using a thermistor anyway b)I just ask the electronics
store for one that goes 0-100C , and a table. That's the
functionality, so the implemenetation - if there are differences ,
makes no difference to me.
If for example I don't get a K-Type plug DMM and K-Type Thermistor.
Are there then any issues with wrapping wire around the legs of a bead
thermistor, tying them to it with insulation tape, and connecting them
to a DMM with crocodile clips?
** Folks - we have ourselves a genuine " live one " here.
Could be a second cousin to Vicky Pollard as well.
Lotsa inbreeding involved - for sure.
..... Phil
|
|
|
|
Author: BlipDate: 10:03 22-05-08
|
|
On Thu, 22 May 2008 22:55:15 +1000, "Phil Allison"
<philallison@tpg.com.au> wrote:
> Lotsa inbreeding involved - for sure.
>
>
>
>
>..... Phil
Wondering what part of sci.electronics.*basic* you don't understand
you stupid cretin...
|
|
|
|
Author: Phil AllisonDate: 10:08 22-05-08
|
|
"Blip" <blip@krumpli.com>
** Blimp ????
> Lotsa inbreeding involved - for sure.
>
> Wondering what part of sci.electronics.*basic* you don't understand
** What part of "live one " is novel to you -
you asinine fuckwit.
..... Phil
|
|
|
|
Author: John LarkinDate: 11:14 22-05-08
|
|
On Wed, 21 May 2008 18:53:06 -0700 (PDT), "jameshanley39@yahoo.co.uk"
<jameshanley39@yahoo.co.uk> wrote:
>I would like to get a temperature probe like this, from an electronics
>place.
>
>How would it be described technically? I know they have specific
>names, for the form of the bit at the end. K-Type e.t.c.
>
>Here is a picture (it is measuring a HDD temp)
>http://www.overclockersclub.com/reviews/nzxt_sentry/images/12.htm
>
>I am also interested in the same question, regarding this probe.
>It is measuring CPU temp
>http://www.overclockersclub.com/reviews/nzxt_sentry/images/9.htm
>
>Note- I know there are other ways. Software, IR Temp sensor Gun, to
>measure temp of components. But I am interested particularly, in these
>temp probes like in the picture. some wires and a thing on the end,
>and you tape it to the component and read the temperature.
>
>Thanks.
>
Omega sells thermocouple probes and meters, and has a lot of notes and
tutorial stuff.
http://www.omega.com/
They have some nice, small, stick-on probes, sort of like tiny
band-aids. Lots of cheapish DVMs will read out type K thermocouples.
John
|
|
|
|
Author: jameshanley39@yahoo.co.ukDate: 11:34 22-05-08
|
|
On 22 May, 10:01, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:
> Phil Allison wrote:
> > "BobG" <
>
> > > You dont need a Type K thermocouple until you get in the 100s of
> > > degrees...
>
> > ** Not true.
>
> > K-type thermocouples are ideal for many applications over a very wide te=
mp
> > range =A0- =A0mainly due to the tiny thermal mass and size of the bead t=
hat has
> > to be heated (or cooled).
>
> > Perfect for small semiconductors, heatsinks and inaccessible spots.
>
> > In any case, most K probes are sold with Teflon coated lead wires and so=
are
> > only safe up to 250 C max.
>
> I agree 100%.
>
> Furthermore, there are many quite inexpensive DMMs with K-type inputs. A K=
-type
> thermocouple is the simplest to use for the non-expert who doesn't want to=
get
> involved in all the fuss with different themocouple materials.
>
> One small point. K-type connectors used to be colour coded yellow. It seem=
s to
> have changed to green now for some daft reason. They are compatible though=
.
>
> Graham-
Can you name some places selling them? I will check if any ship to
britain..
I will look into John Larkin's suggestion too, of cheap DVMs with K-
Type inputs.
According to this site
http://www.picotech.com/applications/thermocouple.html
K-Type refers to the metal the thermocouple (or perhaps, the
thermistor) , is made from. Not the plug.
Is there a chance that a K-Type Thermocouple from one place will not
plug into a Multimeter from another place?
I know for example that probes from one multimeter tend not to fit
into another one.
|
|
|
|
Author: jameshanley39@yahoo.co.ukDate: 11:57 22-05-08
|
|
On 22 May, 02:53, "jameshanle...@yahoo.co.uk"
<jameshanle...@yahoo.co.uk> wrote:
> I would like to get a temperature probe like this, from an electronics
> place.
>
> How would it be described technically? =A0I know they have specific
> names, for the form of the bit at the end. =A0K-Type e.t.c.
>
> Here is a picture (it is measuring a HDD temp)http://www.overclockersclub.=
com/reviews/nzxt_sentry/images/12.htm
>
> I am also interested in the same question, regarding this probe.
> It is measuring CPU temphttp://www.overclockersclub.com/reviews/nzxt_sentr=
y/images/9.htm
>
> Note- I know there are other ways. Software, IR Temp sensor Gun, to
> measure temp of components. But I am interested particularly, in these
> temp probes like in the picture. =A0some wires and a thing on the end,
> and you tape it to the component and read the temperature.
>
> Thanks.
somebody somewhere, dunno if this thread..
mentioned a place called Omega. They have a uk branch..
I just spoke to their Tech.. REALLY GOOD
Just sharing the information here.. I am probably relaying him
wrongly.. But anyhow.. was very helpful.
I said I am just looking to measure temp off a hard drive.
(i.e. just putting / (taping actually) a probe on the bottom on the
back circle just off center (that is how they measure it in the
picture I linked to in my first post)
They said I can't just attach a thermocouple to a DMM, because I won't
get an accurate reading.. They won't have "Fault Junction
Compensation". He said Thermocouple (or K-Type?) sockets are more
common than Thermistor..
I guess maybe the ones with K-Type sockets -do- have that "fault
junction compensation". So give accurate readings.
They mentioned product HH11A =A343.55 - so expensive. An LCD
displaying temperature, with a probe..
(this looks good, a bit like a product called compunurse that is hard
to find in the uk) For 10 quid more. A muiltimeter HHM15/HHM/16
with a temperature reading.
I asked about reading resistance and using a table.. He said nah,
because of the "Fault Junction Compensation" problem.. Don't go down
that route.
He said I would an RTD sensor for that. Not a thermocouple or
thermistor. And RTD sensors, he said are alot more expensive.
|
|
|
|
Author: BobGDate: 12:15 22-05-08
|
|
Well James, if you want to read temperature, and you have a computer,
then a MAX DS18B20 digital thermometer is just what you need. Its
digital. Wire length no prob. My second choice would be an LM35
temperature sensor... puts out analog 10mv/deg C... read it with an a/
d input.
|
|
|
|
Author: Peter BennettDate: 13:04 22-05-08
|
|
On Thu, 22 May 2008 05:22:34 -0700 (PDT), "jameshanley39@yahoo.co.uk"
<jameshanley39@yahoo.co.uk> wrote:
>I see, K-Type refers to the power end, not the sensing end , which was
>what I was wondering about.
No - K-type specifies the types of wire making up the thermocouple -
have a look at Wikipedia for some good info on thermocouples. A
thermocouple generates a very small voltage that varies with
temperature.
>
>I will get a DMM with a K-Type socket .. And a K-Type thermistor to
>match.
Thermistors are resistors whose resistance varies with temperature in
a documented (and usefully large) way. (The resistance of most
conductors will vary with temperature, but usually by too small an
amount to be used as a practical temperature sensor)
>
>Regarding material for the thermocouple. My friend did mention that a
>thermocouple uses 2 different metals, to get a difference in voltage.
>But a)I will be using a thermistor anyway b)I just ask the electronics
>store for one that goes 0-100C , and a table. That's the
>functionality, so the implemenetation - if there are differences ,
>makes no difference to me.
>
>If for example I don't get a K-Type plug DMM and K-Type Thermistor.
>Are there then any issues with wrapping wire around the legs of a bead
>thermistor, tying them to it with insulation tape, and connecting them
>to a DMM with crocodile clips?
Again, K-type refers to thermocouples, not thermistors. With
thermistors, you can use croc clips or other random wiring with no
problems.
With thermocouples, you need to use the right wire and connectors for
the type of thermocouple you have - otherwise every joint between
dissimilar metals forms another thermocouple, which can mess up your
readings.
>
>
>Thanks
--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca
|
|
|
|
Author: EeyoreDate: 14:46 22-05-08
|
|
"jameshanley39@yahoo.co.uk" wrote:
> Eeyore wrote:
> > Phil Allison wrote:
> > > "BobG"
> >
> > > > You dont need a Type K thermocouple until you get in the 100s of
> > > > degrees...
> >
> > > ** Not true.
> >
> > > K-type thermocouples are ideal for many applications over a very wide
temp
> > > range - mainly due to the tiny thermal mass and size of the bead that
has
> > > to be heated (or cooled).
> >
> > > Perfect for small semiconductors, heatsinks and inaccessible spots.
> >
> > > In any case, most K probes are sold with Teflon coated lead wires and so
are
> > > only safe up to 250 C max.
> >
> > I agree 100%.
> >
> > Furthermore, there are many quite inexpensive DMMs with K-type inputs. A
K-type
> > thermocouple is the simplest to use for the non-expert who doesn't want to get
> > involved in all the fuss with different themocouple materials.
> >
> > One small point. K-type connectors used to be colour coded yellow. It seems to
> > have changed to green now for some daft reason. They are compatible though.
> >
> > Graham-
>
> Can you name some places selling them? I will check if any ship to
> britain..
Farnell has them.
http://uk.farnell.com/jsp/search/browse.jsp?N=500005+1002025+106132&Ns=PRICE_PLS_006
_PRICE1%7c0&Ntk=gensearch_001&Ntt=thermocouple&Ntx=lists
some 100+
The simple bare junction type at the top of the list should do you find.
> I will look into John Larkin's suggestion too, of cheap DVMs with K-
> Type inputs.
They're all over the place. Funnily enough often on some of the cheaper Asian meters.
I've found these to be quite satisfactory.
> According to this site
> http://www.picotech.com/applications/thermocouple.html
>
> K-Type refers to the metal the thermocouple (or perhaps, the
> thermistor) ,
It does. The TWO metals in fact.
> is made from. Not the plug.
The plug is colour coded to match the thermocouple, so as to avoid accidentally
mixing up incorrect thermocouples.
http://uk.farnell.com/jsp/search/browse.jsp;jsessionid=VK5NRESE3QUL4CQLCIPZK0Q?N=500005+
1002292+103643&Ntk=gensearch_001&Ntt=thermocouple&Ntx=&_requestid=349800
I see Farnell still stock the yellow type.
> Is there a chance that a K-Type Thermocouple from one place will not
> plug into a Multimeter from another place?
Not if it's the 'standard' plug.
> I know for example that probes from one multimeter tend not to fit
> into another one.
Not if they're 4mm types which all decent meters have.
Graham
|
|
|
|
Author: EeyoreDate: 14:49 22-05-08
|
|
"jameshanley39@yahoo.co.uk" wrote:
> They said I can't just attach a thermocouple to a DMM, because I won't
> get an accurate reading.. They won't have "Fault Junction
> Compensation". He said Thermocouple (or K-Type?) sockets are more
> common than Thermistor..
He said 'cold junction' actually. I don't know how they get round that but trust me they
do work.
However those cheap DMMs with K-type inputs actually perform very well. I 'calibrate'
them with boiling water before
use and it's rare to see one even as bad as 2C out.
Forget thermistors totally.
Graham
|
|
|
|
Author: Rich GriseDate: 15:25 22-05-08
|
|
On Thu, 22 May 2008 05:22:34 -0700, jameshanley39@yahoo.co.uk wrote:
>
> I see, K-Type refers to the power end, not the sensing end , which was
> what I was wondering about.
>
> I will get a DMM with a K-Type socket .. And a K-Type thermistor to
> match.
>
> Regarding material for the thermocouple.
That's what the "K" means.
http://www.rescal.com/Thermocouple alloys.htm
As to the mechanical aspects of the probe itself, you'd probably have
to work with your vendor on that, like look at their catalog pix, or
call them and ask.
Good Luck!
Rich
|
|
|
|
Author: jameshanley39@yahoo.co.ukDate: 17:02 22-05-08
|
|
On 22 May, 19:49, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:
> "jameshanle...@yahoo.co.uk" wrote:
> > They said I can't just attach a thermocouple to a DMM, because I won't
> > get an accurate reading.. They won't have "Fault Junction
> > Compensation". =A0 He said Thermocouple (or K-Type?) sockets are more
> > common than Thermistor..
>
> He said 'cold junction' actually. I don't know how they get round that but=
trust me
>they do work.
>
> However those cheap DMMs with K-type inputs actually perform very well.
> I 'calibrate' them with boiling water before
> use and it's rare to see one even as bad as 2C out.
>
> Forget thermistors totally.
>
I see.. and cold junction is only a thermocouple issue..
So I still use a table of resistance-temperature.. I don't need a
multimeter with temperature.
http://www.omega.com/manuals/index.html?s=3Dh (they are a US and UK
company)
Though his DMM with K-Type input, was very expensive.. 60UKP/$120
He mentioned HH11A $65/30UKP. LED with probe, displays temp.
or as an alternative. the MM approach we are discussing.
HHM15/16. $120/60UKP. Multimeter with K-Type connector (happens to
display temperature)
It displayed temperature, so one didn't need a table.. I was willing
to get one that didn't display temperature, and thus I would use a
table. But I don't think he had any.
I now see - thanks to all the explanations!- that Thermistors have
nothing to do with K-Type and nothing to do with cold Junction
issue. Given that..
Should I still forget thermistors? Can't I get one with a standard
plug that fits a multimeter, too ? And if they can just be wired with
any wires, and don't need to be a special socket on the multimeter.
Isn't that ideal? Better than thermocouple? Or are they expensive?
He didn't mention any multimeter with K-Type connector, that did not
display temperature.
Are there any big places in the US that sell them? They might ship to
UK.
Going off the purpose a bit..Looking at why the tech on the phone said
what he said. I guess he just meant that a DMM(or DVM no doubt) with
K-Type input would have the circuitry to deal with the cold junction
issue. So He was prob saying that because of that, they would not be
inaccurate..I guess he was saying that I can't wire the thermocouple
to a multimeter without K-Type input, because of the cold junction
issue. Though as Peter Bennett said.. that won't work anyway because
the wires would have to be the correct metal. (So I would get the
correct metal wires, by getting a K-Type thermocouple with its own
wires and its own standard plug, which implies a DMM/DVM with that
socket!)
thanks!
|
|
|
|
|
|
|
|
|
Contact | Electronic Portal
|
|
|
