Depression sensor for an electronic ignition advance device for an internal combustion engine

A depression sensor for an electronic ignition advance device for an internal combustion engine, the sensor including a membrane which is deformable in response to the value of said depression, said sensor comprising resistive means of which the ohmic value varies as a function of the value of a force which is applied to them, and an electronic control circuit controlled by said resistive means, said electronic control circuit being constituted by one transistor polarized by a voltage divider and thermal stabilizing bridge connected between the positive pole and the negative pole of the sensor, and another transistor of which the collector and the emitter are in series with said resistive means and a resistance of fixed value, and of which the base is connected to another resistance which is connected by one of its ends to the collector of the first transistor and by its other end to the negative pole of the sensor, said resistive means being connected between the positive pole of the sensor and the emitter of the first transistor so as to be supplied with stabilized voltage by means of said divider and thermal stabilizing bridge, said resistance of fixed value being connected by one of its ends to the emitter of said one transistor and by its other end to the collector of said other transistor so as to cause said output voltage from the sensor to vary linearly, whereby variations in the value of said depression applied to said deformable membrane will vary said force applied to said resistive means and consequently will vary an output voltage of said electronic control circuit linearly with a determined range of depression values.