I'm confused. At 4:28 while the sticker says 27.39mV you say 23.39. 10 seconds later narration again says 23.39. And finally at 5:32 same 23.39.value is repeated while the Fluke actually read 27.40mV from what looked like full deflection at this camera angle but sure parallax effect can make things hard. In the worst case you're only 90 counts off on a 50,000 count 0.025% basic DC accuracy rated meter.
why not use a k-type probe or two, and a multimeter with thermocouple reading ability or two, and then you can calibrate an iron at say 150 degree or 200 degree (or adjust its temperature set value till your thermocouple reads that exactly), and then you know you can leave the iron at that exact temperature, and now get a proper calibration resistor for this meter now that you know it should read exactly 150 / 200. But I also wonder if the (resistor + NTC) needs to be a proper value, in order to match a proper cancellation curve of the cold junction effect? Although maybe then also this effect is so small in the weeds you don't need to worry about it too much, again as you said, for such an instrument. It's cool how the whole thing works purely on physical effects and needs no batteries.
Yes, you could totally make one yourself with a 50uA or 500uA instrument and a K-type thermocouple, If you always work at say 20 or 25 deg room temperature, you could calibrate the cold junction offset for say 22 deg in and then the meter would only be wrong by the few degrees that the actual room temperature differs. No need for a NTC in that case.
@@TheHWcave k-types don't typically reach to above 300 degrees accurately, afaik, for this purpose they are less well suited. But you can transfer the accuracy of one to the other at a medium temperature
I think that one of the challenges is the way that Solder interacts with the K-type Junction. There can be oxidization issues, so perhaps they use Iron / Const to provide better long-term stability
@@TheHWcave - you know the little bulk packs of Hakko 3-way junctions, and the new version sensor AS5000 for FG- 100B.... I wonder what kind of junctions they use? I wasted far too long searching, and didn't test my Hakko to try and determine what it uses. My idea was that if Hakko used Iron/Constantine then maybe you could adapt one of those onto this gadget instead of adjusting for the aged probe. 😉
Somehow I say 23.39mV when it should be 27.39mV sorry about that.
Nice project, well done.
I'm confused. At 4:28 while the sticker says 27.39mV you say 23.39. 10 seconds later narration again says 23.39. And finally at 5:32 same 23.39.value is repeated while the Fluke actually read 27.40mV from what looked like full deflection at this camera angle but sure parallax effect can make things hard. In the worst case you're only 90 counts off on a 50,000 count 0.025% basic DC accuracy rated meter.
Somehow I got 23.39 in my head when it really was 27.39. Sorry
why not use a k-type probe or two, and a multimeter with thermocouple reading ability or two, and then you can calibrate an iron at say 150 degree or 200 degree (or adjust its temperature set value till your thermocouple reads that exactly), and then you know you can leave the iron at that exact temperature, and now get a proper calibration resistor for this meter now that you know it should read exactly 150 / 200. But I also wonder if the (resistor + NTC) needs to be a proper value, in order to match a proper cancellation curve of the cold junction effect? Although maybe then also this effect is so small in the weeds you don't need to worry about it too much, again as you said, for such an instrument.
It's cool how the whole thing works purely on physical effects and needs no batteries.
Yes, you could totally make one yourself with a 50uA or 500uA instrument and a K-type thermocouple, If you always work at say 20 or 25 deg room temperature, you could calibrate the cold junction offset for say 22 deg in and then the meter would only be wrong by the few degrees that the actual room temperature differs. No need for a NTC in that case.
@@TheHWcave k-types don't typically reach to above 300 degrees accurately, afaik, for this purpose they are less well suited. But you can transfer the accuracy of one to the other at a medium temperature
I think that one of the challenges is the way that Solder interacts with the K-type Junction. There can be oxidization issues, so perhaps they use Iron / Const to provide better long-term stability
@@johncoops6897 I agree which is why I did not want to mess up my good K-type probes
@@TheHWcave - you know the little bulk packs of Hakko 3-way junctions, and the new version sensor AS5000 for FG- 100B.... I wonder what kind of junctions they use?
I wasted far too long searching, and didn't test my Hakko to try and determine what it uses.
My idea was that if Hakko used Iron/Constantine then maybe you could adapt one of those onto this gadget instead of adjusting for the aged probe. 😉
👍👍👍👍👍