Pressure regulator for a fuel cell system

An anode side has an inlet (3.2) into a fuel cell unit for a hydrogen-rich gas and an outlet (3.1) for anode exhaust gas. A cathode side has an inlet (4.1) into the fuel cell unit for oxygen-rich gas and an outlet (4.2). A pressure regulator (1) has a membrane (5) to separate the pressure regulator into anode (6) and cathode (7) areas while affected by pressure from both sides.