A different look at your PCB – Infrared
![iMX6 Rex Infra-red comparision image](https://assets.fedevel.com/blog/2019/10/4bf6f-imx6-rex-infra-red-comparision-image.jpg)
Here are some pictures of the same PCB, but running different software applications:
- Notice the CPU temperature difference when nothing is running (49.9°C) and when a test is running (76.4) – compare the first and third picture.
- Have a look at the picture in the middle. Memories become more visible when running a memory test.
- See the huge difference in Ethernet temperature when Ethernet cable is connected (the middle picture, bottom right corner) and disconnected.
- It’s interesting to see, how the whole PCB will warm up from a few hot components – the module PCB is much warmer than the Baseboard PCB (in background).
Picture: Uboot only (Ethernet unplugged).
![01 uboot without eth module](https://assets.fedevel.com/blog/2019/10/05f18-01-uboot-without-eth-module.jpg)
Picture: Memory test (Ethernet connected)
![03 stresstest mem module](https://assets.fedevel.com/blog/2019/10/f9e30-03-stresstest-mem-module.jpg)
Picture: CPU test + Memory test (Ethernet unplugged)
![05 stresstest cpu+mem eth unplugged module](https://assets.fedevel.com/blog/2019/10/32526-05-stresstest-cpumem-eth-unplugged-module.jpg)
If you use a hot air gun, how the heat will spread on PCB?
This was also an interesting experiment, we used a hot air gun (you can see it on the right picture) to heat up a small PCB. Notice, how the middle GND exposed pad is much colder then the area without copper (note: the result may be affected by the shiny surface of golden areas).![SPS bottom gun rear1 180°C comparision](https://assets.fedevel.com/blog/2019/10/30c3e-sps-bottom-gun-rear1-180c2b0c-comparision.jpg)