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I did some "temperature measurements" myself (unpublicable - in the car in the sun ), and it seemed to me that (IMHO) meters have some internal (software-firmware) compensation for common temperature range (up to about 45 deg C), because meters are very stable in that range.
I consider that as "cheating".
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P.S. LCD displays of the meters do not like hot+sun - do not ask how I know! Fortunately it is almost reversible.
Nonlinearities in tempco come firstly from reference chip alone. And also all kinds of compensations.Bandgap reference is basically tempco compensation circuit.
Software compensation (lookup table or polynomial or whatnot) is advanced technique I doubt would be used in cheap meter.. And all of them are compensated for minimum error at normal work temperatures, at the expense of larger errors where nobody cares.. It's not cheating, it's clever engineering..
Canadian winters running a DMM even at -20°C the test leads get very hard and brittle, the LCD display fluid starts to freeze up, alkaline batteries crap out too.
I think 0°C is the lowest any DMM is good for.
This.
I don't do measurements in Siberia at -55°C. Nor I do measurements at 60°C. When temps reach 40° it becomes unsafe for people to work. I would never use my meters that I payed for at those temps, for fear of being damaged or at least being knocked out of specs.. Batteries leak, or explode (Samsung Galaxy7 ?), LCD gets damaged, plastic gets brittle or soft, so it breaks or deforms.....
It is unneeded to test outside of temp specs of device. It doesn't matter what it shows.. You can't trust it, and if you plan to do it on a regular basis it might damage your equipment. Manufacturer clearly told you , when you bought it, in specifications, that if you measure something while at 60°C meter might start showing elephants instead of Ohms, for all they care.
Unless it is a special meter specified for those temps..
I really like that Joe tries to find breaking point for voltage resilience. That is useful information. If meter gets killed by grill starter, yeah, that means your carpet can kill it.. That is something that is very likely gonna fail in service.. Also overvoltage events are unpredictable and dangerous.. So all info that shows a bit more about that is nice. And also Joe doesn't test outside of specs when testing overvoltage.. If anything, he tests at energies that are much smaller than IEC testing standards prescribe.
Of course I'm not trying to patronize anybody to tell them what to do. I like Joe's videos, and he might chose to make some that have entertainment value more so than engineering one.. That is fine.
I'm just saying that these numbers do NOT have real-world practical meaning, as some viewers seem to think.
I assure you, Joe knows that very well, too.. But he is allowed to have a bit of fun in his own private time, and that is what he does.
I just think it's a shame that he seems to have access to real thermal chamber, and is more than qualified to make real, useful thermal characterization for equipment.
So he could do it that way and finally we would be able to see some numbers manufacturers are hiding like snake is hiding legs...
But of course, it is a serious, time consuming project and I understand if he just don't have time to do it. And that is also fine with me..