Abstract: A method for measuring acceleration or mechanical forces, the acceleration causing inertial forces, uses a transducer or accelerometer in which at least one piezoelectric element is influenced by a shearing force substantially parallel to the polarization axis of the piezoelectric element, where the shearing force is created by a component of a mechanical or an inertial force substantially perpendicular to the polarization axis. A transducer for measuring acceleration or mechanical forces, the acceleration causing inertial forces, includes at least one piezoelectric element and at least two spaces surfaces abutting the piezoelectric element and arranged so that they are mutually displaced by a component of a mechanical or an inertial force acting substantially in a direction perpendicular to the polarization axis of the piezoelectric element.

Abstract: An apparatus for detecting the malfunctioning of an accelerometer (4), where a test signal in the form of a pulse is transmitted from a test signal generator (3) to the accelerometer (4) by a change-over switch (1,2) capable of performing a change to transmit the response signal from the accelerometer (4) to an analyzing circuit (8) so as to be subjected to a malfunction detection. The change-over switch (1, 2) is adapted to alternately connect the accelerometer (4) either to the test signal generator (3) or to the analyzing circuit (8). A particularly simple circuit is obtained wherein the response signal in the form of a ringing is not connected to the analyzing circuit until after the pulse has been transmitted by the test signal generator.

Abstract: A method for measuring acceleration or mechanical forces, the acceleration causing inertial forces, uses a transducer or accelerometer in which at least one piezoelectric element is influenced by a shearing force substantially parallel to the polarization axis of the piezoelectric element, where the shearing force is created by a component of a mechanical or an inertial force substantially perpendicular to the polarization axis. A transducer for measuring acceleration or mechanical forces, the acceleration causing inertial forces, includes at least one piezoelectric element and at least two spaced surfaces abutting the piezoelectric element and arranged so that they are mutually displaced by a component of a mechanical or an inertial force acting substantially in a direction perpendicular to the polarization axis of the piezoelectric element.

Abstract: A method for determining a displacement of an object of an electrically conductive material. The method includes the step of using a transducer to establish an electromagnetic field for creating eddy currents in the object. This results in a first electrical signal representing the impedance of the transducer; the direction and magnitude of the electrical signal are represented by a first vector having first and second components. The first component is a second vector dependent on the characteristics of the transducer and on the distance between the transducer and the object. The second component depends on the characteristics of the transducer, the distance between the transducer and the object, and the object's characteristics (e.g., the electrical conductivity, permeability, and temperature). The first electrical signal represented by the first vector is then processed to generate a second electrical signal corresponding to a separate vector.

Abstract: A method and a system for testing one or more transducers, preferably acoustic transducers, from a central control unit. The transducers are individually connected to the inlet of a preamplifier (4) having a relatively high input resistance (6). A test conduit extends from the central control unit to each transducer. The test conduit communicates with the joint between the transducer and the inlet of the preamplifier (4) through a relatively small capacity (10). In this manner a method is obtained for testing the transducer, said testing being highly sensitive to the condition of the transducer and relatively insensitive to external fields.

Abstract: Strip chart recorders in which the curve is recorded by means of a rotatable pen (11) which traces the curve in a line of contact (14) being a generatrix of a supporting roller (15), suffer from a plotting error originating from the fact that the ordinate of the curve, which should be proportional to the angle of deflection v of the pen, is proportional to the tangent of said angle. This plotting error, that makes it impossible to carry out measurements on the curve, can be compensated for by incorporating in the position servo, which serves to overcome frictional losses in the recorder, a position sensor of a differential capacitor type (20, 22, 23) the differential capacitance of which, as a function of the angle of deflection v of the pen, is proportional to the tangent of v.