Pirani Gauge: Working Principle, Low Pressure Measurement By Wheatstone Bridge

In this video we are going to see the working principle of Pirani Gauge. So here is the diagram in which one arm of Wheatstone bridge is taken out in glass bottle, one end of this glass whose pressure is to determined. the temperature of heating element depends upon thermal conductivity of gas. thermal conductivity increases if gas pressure increases. hence if gas pressure increases, temp of heating element decreases which in term changes resistance of wire. this change in resistance of wire is determined by milli-ammeter. Pirani gauge is used to determine very low pressure.