Welcome to a new Voltlog, today I’m gonna show you some techniques that you can use when doing temperature measurements. Typically you will want to measure either the ambient temperature or the system or component temperature. Depending on one of these goals you are going to follow different design rules to achieve that. And to better illustrate the problems, I have these 3 pcbs which have exactly the same electrical circuit but with different layouts on the pcb.
The boards consist of an esp8266 and a digital temperature sensor and you might expect that since all 3 boards are placed so close together, they should all indicate the same temperature but that is not the case as we can see on this graph we are getting 3 different temperatures and only one of them is close to the actual ambient temperature measured with another thermometer, so why is that happening? Well the answer lies in the layout of the PCB and that includes component placement, copper planes and various other elements on the PCB.