The one-way sensor unit has a sensor provided around an electrical quantity, which is based on a quantity that has to be determined. A signal terminal is provided around an outlet for the electrical quantity. A supply terminal is provided around the sensor with an electrical supply quantity. A connection is accommodated along the signal terminal and the supply terminal. Another signal terminal is provided around another outlet for the electrical quantity. Another connection is accommodated along the latter signal terminal. An independent claim is also included for an observation system for patient observation, which has, an observation unit.
