Construction and properties of sub-miniature pressure pickups

Summary Two manometers for dynamical measurements (up to frequencies of the order of 50 Hz) are described which were developed for measuring blood pressure in cardiac catheterization studies and for measurements in pneumatic controllers respectively. The principle of a differential transformer was used in which the core was entirely borne by a phosphorbronze membrane. The diameter of the blood pressure manometer is 2 mm (fitting to no. 6 catheter), its length 10 mm. The most important properties of the manometers are to be found in § 4.