Very nice demo and explanation! I've designed and built a couple Pirani gauge controllers in the past. Conventionally, these controllers balance the Wheatstone bridge by altering the supply voltage and keeping the voltage difference between the dividers 0. If you can keep the resistance of the wire stable, you inherently keep the temperature stable (at around a 100-120C). The big benefit of this is if you use a fixed supply as you do now, you run the risk not enough energy gets taken out of the wire at lower pressures, making it run at a higher temperature, meaning it degrades quicker and you need more frequent calibration and replacements! But accuracy with Pirani gauges is something you shouldn't want to chase anyways. The biggest issue is that your measurements are heavily dependent on the mixture of the gas you're pumping away and the surrounding temperature of the measurement head. The ones used in laboratories usually give a figure around +/- 50% accuracy hahaha. Order of magnitude is significantly more important when measuring the quality of a vacuum, you can measure up around 10^-3 mbar until cooling of the wire through the electrical contacts starts to become the dominant effect on the temperature of the wire! You did a great job even making your own sensor. It shows anything is possible on a bit of a budget being handy. All values are in the correct ballpark, I think your sensor can be about as accurate as the ones commercially available! Contact me if you ever need help designing / characterising your own controller for your gauge!
Do you think its possible to cut the wire/glass base off of an old vacuum tube and use it for feed throughs in a new tube like this? I think it would be a really good way to get lots of feed throughs but I'm unsure if its feasible to attach the cut piece to a new glass tube?
@@thesciencefurry I know the vast majority of vacuum tubes utilize borosilicate glass as they use kovar glass seals, but it would be hard to tell the grade of the borosilicate. Might be worth a try though!
