monitoring the package temperature - Page 1
Forum section: electronics / beginners

author: metebalci
author_rank: Frequent Contributor
timestamp: January 23, 2022, 12:41:16 pm
content: I would like to monitor the temperature of ICs/transistors etc. when prototyping, to be sure they are in safe operating area. Is the easiest/best/good enough method to use a PT1000 and attach it to the IC package with a thermal compound ? or something else ? or should I not bother with these and find a thermal imaging solution ?

author: magic
author_rank: Super Contributor
timestamp: January 23, 2022, 01:36:58 pm
content: Thermal imaging is a bit exotic/expensive stuff.Thermocouples are cheap and low thermal mass sensors that can be glued to stuff with sticky tape. At a moderate expense I have bought a very fine thermocouple (0.1mm wire diameter) - it works fast and fairly accurately even without gluing (thin wires → low thermal conduction through the sensor itself), which is to say, probably to a ± few degrees but that's good enough in such application.This is an interesting device, but the lack of distributors, the shipping costs from them to Europe and the EU VAT have so far successfully discouraged me from buying it. And I can't find alternative products with similar functionality. There was a Chinese clone of unknown quality years ago, but it's long gone (lawsuits?).https://www.thermoworks.com/close-focus-ir/

author: rpiloverbd
author_rank: Regular Contributor
timestamp: January 23, 2022, 01:59:23 pm
content: You can also use an LM35 or DS18B20 and Arduino/any other microcontroller of your choice. If you use arduino, you'll be able to see the temperature in your serial monitor. That will save the cost of any extra display.

author: magic
author_rank: Super Contributor
timestamp: January 23, 2022, 02:04:17 pm
content: TM-902C costs a few bucks, probe included.And anything TO92 has huge thermal mass, have fun waiting for it to catch up to the temperature of whatever you placed it on. And they top out at 125°C, although if your project runs that hot then maybe you are doing it wrong

author: metebalci
author_rank: Frequent Contributor
timestamp: January 23, 2022, 02:36:19 pm
content: Quote from: magic on January 23, 2022, 01:36:58 pmI said PT actually because I can directly connect it to the DMM without any other device and PT temperature range is more than enough. I see PT sensors usually with capsule and I was looking to get an individual thin film PT100/1000 component rather than a probe/like the one sold by adafruit etc., but it is still not a bare wire. I guess then the response time of thermocouple is better than PT100/1000 ?

author: Jeroen3
author_rank: Super Contributor
timestamp: January 23, 2022, 02:54:18 pm
content: A thermal camera.Get yourself a Seek Thermal to attach to your phone. It's worth it when brining up boards and finding defects!Second choice would be a thermocouple meter. The RTDs are too big, too slow.You can attach them with a bit of polyamide tape.

author: metebalci
author_rank: Frequent Contributor
timestamp: January 23, 2022, 03:12:24 pm
content: Quote from: Jeroen3 on January 23, 2022, 02:54:18 pmOK thanks. I used a thermal imaging accessory before but not for electronics. I guess it does not matter the accuracy or the effects of the environment for this application, correct ?

author: Jeroen3
author_rank: Super Contributor
timestamp: January 23, 2022, 05:01:52 pm
content: You can't really use them in direct sunlight or with reflective parts (tops of aluminum caps) but other than that, they're great to view heating ic or even illuminate traces to shorts on a pcb.They are within a few degrees accurate.

author: metebalci
author_rank: Frequent Contributor
timestamp: January 23, 2022, 06:04:03 pm
content: OK thanks. I will try these.

author: metebalci
author_rank: Frequent Contributor
timestamp: January 23, 2022, 07:10:04 pm
content: I just saw a TI paper (ref below), and my summary from that (similar to the points above):- order of accuracy (paper date 2016): IR camera, fluor-optic probe, thermocouple, IR gun (max field of view 4mm diameter)- thermocouple: 36 to 40 gauge J or K wire. It is important for wire to be thin, 36+ gauge.- it is better to attach the thermocouple with a thermally conductive epoxy, taping is not recommended.- when using an IR camera or IR gun, reading should be corrected for emissivity of the surface.More info on section 3.1 Case Temperature Measurement of :https://www.ti.com/lit/an/spra953c/spra953c.pdf