A digital sensor has a sensor element, a digital section, a sample-and-hold stage and an output stage, and storage storing electrical energy, each of which are supplied with electrical energy by a power supply. In the event of a failure of the power supply, the sample-and-hold stage and the output stage are provided with power by the storage storing electrical energy, such that the measurement value most recently stored in the sample-and-hold stage is provided in the signal line by the output stage until the failure of the power source has ended and a new measurement value is stored in the sample-and-hold stage. No electric power is supplied to the sensor element by the storage storing electrical energy in the event of a failure of the power supply.