Fast, thermostatic, Pirani gauge
C. J. MILNER · Review of Scientific Instruments · 1983
The Wheatstone bridge of a Pirani gauge has been made self-balancing, and the gauge thermostatic, using a simple but novel dual op-amp circuit. The system retains the electrical and pneumatic robustness, and the atmospheric to high-vacuum pressure range, characteristic of conductance-type gauges. Without recourse to ultrathin material for the temperature-dependent resistor, response time constants (dependent on bridge setting) of 0.1 s, of 2.5 mPa; or an impulse of pressure change, occurring within 50 ms, of 0.25 mPa s. The circuit described is also applicable to bolometric power measurement, where fast response is required.