Electronics for pirani gauge

Estimate reading time: 2 minutes

I was working on electronic part of pirani gauge a few weeks, so there were no new posts.. I moved the system from breadboard to the plastic box, added display and microprocessor. Measurement and control of the display is based on arduino.

I am not going to describe the function of pirani gauge, there is a lot of information on the web. All the electronic system is taken from this pages, I only added a pull-up resistor for wheatstone bridge, because after turning it on, the voltage on bridge stayed on 0 – both branches were equal, so now the static branch is slightly (xM ohm resistor) pulled up. I also added a atmega, low-pass filter on voltage reference, display..

Range of the gauge is from 3.3V (maximal voltage, atmospheric pressure) to somewhere around 0V. It is not calibrated yet.


Pirani gauge unit, on/off led, switch. The knob on the right is used to balance the output voltage to 3.3V – compensation of temperature and atmospheric pressure differences. The pirani gauge itself is in front of the box.


Back view, supply port on the left, pirani sensor port on the right.



I am going to place a PCB and scheme here..