Device and method for operating an electric unit

The device (1) has an interface (11) connecting a first electrical unit (2) i.e. sensor module (3) and a second electrical unit (9) i.e. control apparatus (10) together to supply energy to the first electrical unit by the second electrical unit. The first electrical unit comprises a rechargeable energy storage unit (6) i.e. capacitor, and a control unit (7) controls the device such that the interface supplies the energy to the energy storage unit from the second electrical unit in a first operating mode and transmits information in a second operating mode. An independent claim is also included for a method for operating first and second electrical units.