Abstract: In a process for automatically detecting the response of an electromagnetic valve, in particular an electrovalve, an increasing testing voltage is applied to the valve and the instantaneous testing voltage at which the electromagnetic valve responds is fixed and indicated in that the monetary decrease of the current flowing through the valve is detected and utilized for fixing and indicating the instantaneous value of the testing voltage. A device for automatically detecting the response voltage of the electromagnetic valve includes an indicating device (8) which is controllable in such a way that it indicates and fixes the value of the testing voltage applied to the electromagnetic valve as soon as the valve responds to the testing voltage.

Abstract: A Schmitt trigger circuit is caused to oscillate by a time-constant circuit including a reference inductor. The changing inductance of a variable inductor, for example, an inductive transducer for measuring mechanical movements, is switched into the same circuit, and the length of pulses resulting is measured in comparison with the stored value of the pulse length produced by the comparison inductor, which needs to be put in circuit only at longer intervals. With two Schmitt trigger circuits, one controlled by the comparison inductor and maintained in oscillation, while the other is controlled by the variable inductor and is triggered in synchronism with the oscillating Schmitt trigger, a pulse having a length representing the difference between the inductances of the comparison and variable inductors can be simply produced at frequent intervals. Several variable inductors can be continually measured with reference to a single comparison inductor.