Power supply of a detection unit

A power supply device (1) for supplying power to a consumer disposed on a rail vehicle, the rail vehicle having at least one conductor (4) and the power supply device (1) being configured for generating a supply voltage of the consumer (2) from a voltage applied to the conductor (4), wherein transmission electronics (5) and a bypass conductor (6) connectable in an electrically conductive manner to the consumer (2) via the transmission electronics (5) are provided and the transmission electronics (5) is switched between the bypass conductor (6) and the consumer (2) and the bypass conductor (6) is connected in an electrically conductive manner to the conductor (4) of the rail vehicle, by means of two fastening interfaces (8), a potential difference being present between the fastening interfaces (8) and the bypass conductor (6) being designed in such a manner that the bypass conductor (6) generates an output voltage which is lower than the potential difference at the conductor (4) between the fastening interfaces (8), the transmission electronics (5) being designed in such a manner that the transmission electronics (5) generates the supply voltage of the consumer (5) from the output voltage of the bypass conductor (6).