Single-winding magnetometer with Schmitt trigger output circuit

Magnetometer for time coded measurement of constant magnetic fields, comprising at least one sensor having

• a magnetizable rod-shaped core (20) and
• a single winding (19) disposed on the core, the winding carrying an alternating current and voltage (U.sub.h) for generating an auxiliary alternating magnetic field which magnetizes the core (20) up to and into saturation alternately in each of two directions and, together with the magnetic field that is to be measured, generates a measurement voltage (U.sub.m1), the positive and negative half-waves of which deviate from one another as a function of the magnetic field that is to be measured and which serve to indicate the magnitude of the magnetic field that is to be measured, and wherein
• the measurement voltage (U.sub.m1) is applied to the input of a Schmitt trigger switch (25) having switching limits that are symmetrical to one another and an output which is a rectangular-wave voltage signal (Uy), the duty cycle of which is a measure of the magnetic field detected by the core (20);
• means are provided for generating the axuiliary alternating field, including a triangle generator (17) generating said alternating voltage (U.sub.h) connected to the winding (19) disposed on the core;
• and means (18,21) are provided, for subtraction of said alternating voltage (U.sub.h) from an output voltage signal (U.sub.m) of the winding (19) to obtain said measurement voltage (U.sub.m1), and for amplification of the measurement voltage (U.sub.m1), prior to its application to said Schmitt trigger switch (25), wherein one end of the winding (19) is connected to one input of a subtracting amplifier (21) and one output of the triangle generator (17) is connected with the other input of the subtracting amplifier, the other output of the triangle generator (17) and the other end of the winding (19) being connected to a common reference voltage level, and the output of said subtracting amplifier (21) is connected to said input of said Schmitt trigger switch (25).