Abstract: Pressure sensing apparatus in which a mounting structure carrying a thin, pressure sensitive resistance wire is lodged in a gas passageway extending through an outer member. The mounting includes a relatively large end portion which extends substantially across the passageway to both shield the wire from direct impact by passing gas, and limit the flow of such gas by occluding the passageway. The secure wire mounting apparatus makes possible the use of very thin wires and a corresponding increase in pressure sensitivity resulting from temperature and gas thermal conductivity. The wire diameter is no more than about 0.00005 inch, making possible results comparable to much more expensive mass spectrometer techniques.An overall pressure sensing system is described in which the sensor is coupled with electric circuitry to produce transient and/or absolute pressure readings over an approximately nine decade pressure range. Transient readings of gas temperature and thermal conductivity may also be made.