Abstract: An on-board electrical system for a vehicle comprising: a first energy store; a second energy store; a DC/DC converter bidirectionally transferring energy between the first energy store and the second energy store; and two switching devices for coupling a first terminal of the second energy store to a first terminal of the first energy store via a first node, a second node, and a third node.

Abstract: An on-board electrical system for a vehicle comprising: a first energy store; a second energy store; a DC/DC converter bidirectionally transferring energy between the first energy store and the second energy store; and two switching devices for coupling a first terminal of the second energy store to a first terminal of the first energy store via a first node, a second node, and a third node.

Abstract: A method for controlled connection of a plurality of on-board power system branches is disclosed, wherein electrical power is exchanged between first and third on-board power system branches if an uncritical supply state is present and electrical power is exchanged between second and the third on-board power system branches if a critical supply state is present in the first or third on-board power system branch. In a critical supply state, the first on-board power system branch is disconnected from the third on-board power system branch by opening a first switching device, and the second on-board power system branch is then connected to the third on-board power system branch via a second switching device. A second actuation device that actuates the second switching device receives a switch state signal from the first actuation device and closes the second switching device only if the received signal signals an open first switching device.

Abstract: In an anti-theft system for a motor vehicle, an oscillating circuit of a transceiver in the motor vehicle is modulated with code information of a portable transponder. A demodulator detects the code information and carries it onward to a computer unit, where it is checked for authorization. Component tolerance or temperature changes can mean that initially no code information will be demodulated, despite a properly functioning transponder. According to the invention, the frequency of the modulated oscillation is then measured and reregulated to a command frequency.