NOVELTY - The bridge (100) has first and second shift elements (111, 121) for connecting an alternating voltage terminal (110) with a ground terminal (130) and a positive direct voltage terminal (120). A first heading element (112) is connected to switch the first shift element. A terminal of a capacitor (114) is connected with a power supply terminal of the heading element. The positive direct voltage terminal is connected with the terminal of the capacitor over a diode (113) in a forward direction. The capacitor is parallely switched with a series arrangement of the first and second shift elements.    USE - Half bridge for an active rectifier such as an active and/or steered bridge rectifier, a blocked alternator frequent bridge rectifier and passive and/or uncontrolled bridge rectifier, of a five-phase generator in a DC system for a battery of a motor vehicle onboard network.    ADVANTAGE - The heading element is connected to switch the first shift element, the terminal of the capacitor is connected with the power supply terminal of the heading element, the positive direct voltage terminal is connected with the terminal of the capacitor over the diode in the forward direction, and the capacitor is parallely switched with the series arrangement of the first and second shift elements, thus reducing load of an active bridge rectifier and power consumption of a capacitive working element in a DC system, protecting electric components from overvoltage damage, avoiding short circuit of the half bridge and ensuring prolonged service life and better overvoltage protection function of the half bridge.    DETAILED DESCRIPTION - The first and second shift elements are designed as a MOSFET element. The first heading element and a second heading element (122) are designed as an amplifier element. The positive direct voltage terminal is connected with a third heading element (132) that is designed as a hysteresis element.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic circuit diagram of a half bridge of an active rectifier with an overvoltage guard.    Half bridge (100)    Alternating voltage terminal (110)    Shift elements (111, 121)    Heading elements (112, 122, 132)    Diodes (113, 123)    Capacitors (114, 124)    Positive direct voltage terminal (120)    Ground terminal (130)