Device and method for separating and connecting two-part board networks

A device for disconnecting and connecting two on-board electrical subsystems, the device comprising two series-connected switching elements and a control device, wherein the control device generates control signals for the switching elements depending on measured actual values and previously defined reference values of the on-board electrical subsystems, wherein the switching elements in each case are a parallel circuit consisting of a diode and a controllable resistor, wherein the controllable resistor can be controlled between a low-resistance minimum value and a high-resistance maximum value, wherein the switching elements are arranged such that the two anodes or the two cathodes of the diodes are interconnected,

• wherein a regulator of the switching elements is designed at least partially as hardware, being designed such that a control signal is generated for a switching element to set a resistance value between the minimum value and the maximum value, wherein at least one control unit is allocated to the switching elements, said control unit being designed such that the control unit generates a control signal for a switching element depending on a signal of the control device to set said switching element to the minimum value or the maximum value, wherein the device has at least one switchover device controllable by the control device, by which one switching element is connected to the regulator and the other switching element is connected to the at least one control unit.