Abstract: A device for measuring spatial displacement comprises two similar elementary capacitors of a differential capacitor and which share a common movable armature and the two capacitors are used to produce respective pulses whose lengths are compared to produce a third pulse whose length is proportional to the displacement of the armature. In a preferred embodiment, the capacitors are switched in alternation into an oscillating circuit and serve to determine the frequency of oscillation thereof and the time taken for a fixed number of oscillations to be produced with each capacitor switched in is measured to produce the first and second pulses. An adder/subtractor counter is provided which provides a fourth pulse whose length is equal to twice that of the first pulse and the fourth pulse is compared with a pulse whose length equals the sum of the first and second pulses to produce the third pulse.