looking for K type multimeter, and thermistor

[jameshanley39]

hi

I don't have any electronics background

I am looking for a multimeter with a K-Type plug socket,

And a Thermistor with wires going to a K-Type connector so it can plug into it.

I will get a table of resistance to temperature, with the thermistor.

so I can measure the temperature of things.

I tried calling maplin technical(0906... thus expensive), but they said they no longer sell K-Type multimeters. They prob know alot.

He said he thinks any multimeter with K-Type plug would support thermistors and thermocouples.

He suggested I try RS components.

I tried RS components technical (0845..). She mentioned a multimeter. It was extortionate - Fluke 179. =A3211, or =A3266 calibrated. The calibrated one comes with bead type thermocouple. She said she doesn't know if it supports thermistors too. The description only mentioned thermocouple. I asked her - aren't they usually about =A320. She then mentioned another range that was =A340, but I said forget it.

Does anybody know of a multimeter that does what I want? Am I looking at the right price range? =A320. Or should I be looking at =A340? More than =A340 is really too much.

There are cheap multimeters I have seen at maplin at one time, going for 6 quid, just not with K-Type sockets.

thanks

[Donwill]

I don't have any electronics background

I am looking for a multimeter with a K-Type plug socket,

And a Thermistor with wires going to a K-Type connector so it can plug into it.

I will get a table of resistance to temperature, with the thermistor.

so I can measure the temperature of things.

I tried calling maplin technical(0906... thus expensive), but they said they no longer sell K-Type multimeters. They prob know alot.

He said he thinks any multimeter with K-Type plug would support thermistors and thermocouples.

He suggested I try RS components.

I tried RS components technical (0845..). She mentioned a multimeter. It was extortionate - Fluke 179. £211, or £266 calibrated. The calibrated one comes with bead type thermocouple. She said she doesn't know if it supports thermistors too. The description only mentioned thermocouple. I asked her - aren't they usually about £20. She then mentioned another range that was £40, but I said forget it.

Does anybody know of a multimeter that does what I want? Am I looking at the right price range? £20. Or should I be looking at £40? More than £40 is really too much.

There are cheap multimeters I have seen at maplin at one time, going for 6 quid, just not with K-Type sockets.

thanks

As far as I am aware , a type K refers to a thermocouple not a thermistor, they are different in the way they measure temperature. A thermocouple generates a voltage which changes with temperature. A thermistor does not generate a voltage it exhibits a resistance which changes with temperature.

What is it you trying to measure the temperature of and how critical is the size of the sensor. If you were trying to measure the surface temperature of a small grass leaf for example, you could not use a large sensor because it would interfere with the actual temperature of the leaf. You also would have to shield the sensor from external radiation (sunlight or a strong beam of light) So please tell us what you want to do with it. Regards Don

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember " [e-mail]" saying something like:

There are plenty of temp measuring DVMs around at twenty quid. I've got a couple that use K - plugs, dead cheap and they are accurate enough for my purposes. Irrc, CPC supplied them a couple of years ago.

[jameshanley39]

that makes sense.. I heard it refers to type of metal.. and that thermocouple has 2 different types of metal, to create a voltage difference.

I know.. I don't mind measuring resistance and using a table. or measuring voltage and using a table

or reading the temperature off an LCD display that displays temperature.

this one measuring a hard drive temperature (so in that pic, the small sensor goes on the black circle at the bottom of the hard drive. just off center. Quite a small sensor)

maybe also this one measuring cpu temperature [end of that] probe there looks long and tweezer like.

I wonder if there are names for the different ends.

[Harry Bloomfield]

[e-mail] wrote on 22/05/2008 :

K-type is a thermocouple, K-type is the most common thermocouple and the type most commonly used for multi-meters. One should cost you just a couple of pounds or so, but you may need to source a suitable plug.

[Andy Dingley]

Sounds expensive. Try RS or the on-line lab equipmented suppliers instead and get a dedicated lab temperature meter that uses a K type thermocouple. These are really pretty cheap these days.

Get some spare thermocouples too. Simple ones are cheap, bare wire ones are easily broken. One of the easiest ways to break a thermocouple is to try removing or installing it from equipment where you'd have been a lot better off just buying and installing more of them in the first place and leaving them alone once installed.

[Clint Sharp]

In message , Harry Bloomfield writes

Yeah but don't forget, the cable used to connect the thermocouple will also affect the readings. The OP needs to specify the approximate temperature range he expects to see (0-100c etc.) and then maybe we can work out what he actually needs.

[geoff]

In message , Donwill writes

Does the OP want something like this ?

[John Stumbles]

Toolstation do the Laser brand ones. Not very accurate though.

[Derek Geldard]

Nooooooooooooooooooo !

Type K refers to a type of thermocouple, this is a device formed from a junction of 2 dissimilar metals. It gives a voltage which varies according to the difference in temp. over the whole circuit so you need to know the ambient temp to start with.

However the multimeter typically does all that for you.

Yes, about toy plastic helicopters and ghetto blasters :(((

Take a look here :

has what they describe as a temperature test function. This might do what you want.

Unlikely.

Type K only, there are others.

2 for a fiver even.

There's more than just the socket involved.

DG

[mick]

Agreed... Found one at Rapid!

to measure everything, but I don't know what accuracy is required.

[Dave Plowman (News)]

Why a K-type connector? I have two multimeters that measure temperature - a Maplin and a Fluke and they both use standard banana plugs for the probe lead.

I'd check on Ebay. Loads of different multimeters on sale there and some will do temperature. Not sure about the socket, though.

[jameshanley39]

o.uk wrote on 22/05/2008 :

0-100C

Not sure what wires to buy with the thermocouple..

I have heard that a thermocouple needs to be plugged into a special socket for it.. e.g. K-Type thermocouple into a socket for K-Type thermocouples.

So the multimeter geoff linked to wouldn't do it.. I didn't see that socket on it.. though the picture was not big.

How about using a thermistor instead.. 'cos if that doesn't require any special socket, wouldn't it be better?

I will call that company geoff and donwill and perhaps others too, have mentioned. That CRC company. Their lines will be open tomorrow..

thanks

[jameshanley39]

thanks.. I understand now.. about the Type-K(which I see only applies as a type of thermocouple), and I see the difference between thermistor and thermocouple.

But shouldn't I be able to use a thermistor with a multimeter?

With a table of resistance to temperature.

very interesting find, thanks

[jameshanley39]

my mistakes... my understanading now is that K-Type is a type of thermocouple. Multimeters need a special socket , the the female connector of it is i think some standard connector thermocouples with leads use. The socket's innards have to be for that specific type of thermocouple being used e.g. Type-K.

Is it possible that your probe is a thermistor not a thermalcouple.. I am wondering if maybe thermocouples don't need a special plug.. or even special wires. So it may be easier with a thermistor.

So.. I would agree with your question really.. of why a K-Type connector. Or rather, why a thermocouple - why not a thermistor?

good point.. though the advantage of these electronics places is they have techical support telephone lines.

[Mike Dodd]

Agreed. EBay is your friend, here. A first search of "k-type" (a Freudian slip of entering x-type initially provided very very different results) shows on first page digital thermometers with 2 k-type thermocouples thrown in for £21 (inclusive of P&P) from our friends in China. Further down the pages plenty of spare thermocouples for around £5 each inclusive of P&P.

If you can wait the couple of weeks for shipping then it's a simple no-brainer rather than trying to deal with the high-street or CPC (maybe they're good with tech support over the phone?, all I know is living close by, I've stormed out from their trade counter after 50 minutes of being given the wrong items)

[Andy Dingley]

Thermocouple wires. Special magic ones, from the same shop as the thermocouple.

Yes. Anything with a K type socket can reasonably be assumed to work interchangeably with K type thermocouples, whether this is a temeprature meter, a multimeter that also does temperature, a fridge, oven, kiln or hamster-cosy.

Anything using banana plugs, jacks or phonos is most likely using thermistors or semiconductor sensors, not thermocouples.

There are also two sorts of K type connector. Old ones were yellow, new ones are green. They're not interchangeable, but you can convert equipment by swapping the plugs and socket. Remember that polarity is crucial!

You won't convert a standard meter (voltage or current) to read a thermocouple without sufficint extra work to make it impractical, or sufficient knowledge to appreciate why it's not a practical idea.

My K-type reader cost a tenner or so. They're really not expensive these days.

[whisky-dave]

I don't have any electronics background

I am looking for a multimeter with a K-Type plug socket,

have a couple of these in my electronics lab.

It does come with a probe, which plugs in to the small rectangular green bit near the bottom right hand side of the meter.

[mick]

Because the output from the thermocouple is polarised it uses a special polarised connector on installed systems. There are also standards for the type (& colours!) of thermocouple connecting wire as this affects accuracy of the reading. You need to use Type K wire with a type K thermocouple for example. Using standard banana plugs may be acceptable if your thermocouple is local to the instrument.

Ref:

[Harry Bloomfield]

[e-mail] submitted this idea :

There is nothing special about the socket, other than the electronics at the rear of the socket (the meter's electronics) are calibrated for a K-type.

It does of course also need to be connected the correct way. The cable also need needs to be the correct type for best accuracy, but those probes designed for such use will already be fitted with a short lead anyway.

If you use a thermistor ( can't see why you would want to), then your meter will not provide a direct temperature reading - you will have some maths to do to convert from the reading to a temperature.