A check valve is disposed in a hydrogen offgas circulation path which is connected to a fuel cell so as to flow the hydrogen offgas only in one direction. By setting the gate widths of the gates of these transistors to prescribed lengths, the efficiency of use of elements within the basic cell is improved, and fine adjustment of the threshold voltage Vth and delay time Tpd becomes possible. The first light source is configured to project a first beam of light that primarily lights up a first portion of a target coverage area, and the second light source is configured to project a beam of light that primarily lights up a second portion of the target coverage area, which is different from the first target coverage area. A power control training operation prevents crosstalk from hindering operation on other channels during the training operation. The invention further concerns a terminal element housing with at least one receiving chamber for receiving an electrical terminal element of this kind.