Abstract: A device for controlling electrical power to an oxygen pump portion of a linear oxygen sensor comprises a bridge of transistors controlled by a microprocessor. The microprocessor processes a measurement signal delivered by a measurement cell of the probe in order to control the direction and duration of the passage through an oxygen pump of a current of predetermined strength, the current being controlled based on the measurement signal. The current is periodically alternated, and provided with a variable cyclic ratio, by appropriate switching of the transistors in the bridge. The device is used for the measurement of the air/fuel ratio in the mixture supplied to an internal combustion engine.