New multimeter, is the thermometer good or better standalone? - Page 1
Forum section: electronics / beginners

author: ranixon
author_rank: Contributor
timestamp: April 19, 2024, 04:52:43 pm
content: Hi, I'm going to buy a new multimeter because I want a few more things (like capacitance measurement). These multimeters have very few differences and one of them is the temperature measurement, the UT890C+ and UT89X has it while the UT890D+ and UT89XD doesn’t. I want to use it to measure the temperature of for example CPUs coolers in case of overheating, individual electronic components and such. Are these for that use case or is better a, cheap or not very expensive, thermometer?This is for hobby and not to do professional work.Thank you

author: Gyro
author_rank: Super Contributor
timestamp: April 19, 2024, 05:34:08 pm
content: Welcome.I find separate is better. This leaves the multimeter free for use at the same time and broadens the choice of available meters. Separate thermocouple thermometers tend to be pretty much as accurate as the multimeter function. The low cost TM-902C has been around for decades now, I don't think they are manually adjustable like the early ones but are probably still good enough. I haven't checked which other ones are available these days.

author: ranixon
author_rank: Contributor
timestamp: April 19, 2024, 05:59:22 pm
content: ThisThis is the TM-902C, right?This is a good option,And for the multimeters, the UT89XD is a newer version of the UT890D, no? The only differences that I saw is that the UT890 has a live wire test and the UT89X has Led test.

author: BeBuLamar
author_rank: Super Contributor
timestamp: April 19, 2024, 06:39:07 pm
content: Quote from: ranixon on April 19, 2024, 04:52:43 pmFor measuring things like CPU coolers and stuff the DMM is good as you don't need high degree of accuracy. 1 or 2 degrees off wouldn't matter for such an application. It's the thermocouple configuration which is much more important.

author: Gyro
author_rank: Super Contributor
timestamp: April 19, 2024, 07:02:00 pm
content: Quote from: ranixon on April 19, 2024, 05:59:22 pmYes, that's the one. Edit: Often available cheaper with just the basic thermocouple.

author: Kleinstein
author_rank: Super Contributor
timestamp: April 19, 2024, 07:16:56 pm
content: The cold junction compensation with the DMMs is a bit tricky, as the banana plugs are not really made for TC. It needs care with avoiding temperature gradients at the connectors - so ideally don't hand hold the meter. The temperature measurement can still be usefull, just not super accurate.If more accuracy is needed an external 10 K NTC is an option, but need some lookup table. These NTCs can be affordable and quite accurate, at least for more moderate temperatures.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: April 19, 2024, 11:35:02 pm
content: Dave did a video on this....https://youtu.be/AYblSfpKRUk?si=UivcxrVXLjMTNX00There are others too that touch the subject. Like how you can use the temp settings without a thermocouple.The most important part is the DMM must be at ambient temperature.

author: BeBuLamar
author_rank: Super Contributor
timestamp: April 20, 2024, 12:50:26 pm
content: I think for the OP appication the error of a few degrees doesn't matter and thus most DMM with temperature function should be accurate enough. For that kind of requirement the cold junction compensation isn't that cricical either. What is more important in my opinion is to have a thermocouple that can transfer the heat from what you're measuring to the thermocouple well. Some takes a long time to respond and almost never reaches the same temperture as what you're trying to measure.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: April 20, 2024, 01:24:55 pm
content: Good Morning Ranixon, if you are doing temp. measurements often, then the TM-902C you mention, might be right for you, as your DMM won't be tied up doing temps. Many/most DMMS have temp. measurement and are all fairly accurate. Some take the connectors like the TM-902C, and some use banana plugs, and adapters are available to use either on either system. And don't forget the boiling water/ice water method to check the accuracy of whatever you get. I haven't seen Dave's video that was mentioned, and I too will watch it when I have an extra half hour. Also,you should take advantage of the reason to get another DMM.

author: ranixon
author_rank: Contributor
timestamp: April 25, 2024, 08:43:02 pm
content: Thank you for all your answers, I bought the UT890D+, a bit cheaper than the UT89XD with no big diferences, and will bout the TM-902C or something similar later.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: April 26, 2024, 01:11:33 pm
content: Quote from: ranixon on April 19, 2024, 04:52:43 pmThe UT890D+ does not do temperature,......Isn't temperature measurement what you were originally seeking

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: April 27, 2024, 07:52:35 am
content: Quote from: ranixon on April 25, 2024, 08:43:02 pmBeware the UT890D+ doesn't meet any kind of safety standards, a 5×20mm glass fuse (which they appear to use from the user manual) is not safe in high Voltage/current circuits, not even on mains Voltage.For not much more money you could have bought a Brymen meter, which is certified by the US Underwriters Lab (UL listed) and as recommended (and sold) by Dave Jones (Mr EEV).This is from the BM235 user manual, I have one of these meters:Safety:Certified per IEC/UL/EN61010-1 Ed. 3.0, IEC/UL/EN61010-2-030 Ed. 1.0,IEC/UL/EN61010-2-033 Ed. 1.0, IEC/UL/EN61010-031 Ed. 1.1 and the correspondingCAN/CSA-C22.2 regulations to Measurement Categories:CAT II 1000V, CAT III 600V and CAT IV 300V AC & DCSJ

author: ranixon
author_rank: Contributor
timestamp: July 19, 2024, 05:37:55 pm
content: Quote from: Solder_Junkie on April 27, 2024, 07:52:35 amSorry to not answering earlier, there are no Brymen meters in my country and import it would have made it more expensive, and the BM235 is way more expensive in Ebay than the UT890D+, unaffordable for me

author: ranixon
author_rank: Contributor
timestamp: July 19, 2024, 05:46:40 pm
content: Quote from: BILLPOD on April 26, 2024, 01:11:33 pmNot exactly, it was a "nice to have", but an standalone thermometer is cheap and better to have it separated for my needs. I also didn't know about cheap thermometers like the TM-902C exist.