NOVELTY - The arrangement has a thermoelectric generator (TEG) (1) comprising a hot side (5) for receiving heat from a heat source and a cold side (6) for releasing the heat to a heat sink i.e. cooling fluid line. The TEG comprises electrical terminals (8a, 8b) for supplying electrical power with output voltages, where inputs of an electric circuit (9) i.e. direct current (DC)-DC converter, are connected with the electrical terminals. The TEG is designed such that saturation of the output voltages occurs when the output voltages lie below or reach highly permissible input voltage of the circuit.    USE - TEG and DC-DC converter arrangement for use in a waste gas system of a combustion engine (all claimed) for converting heat energy into electric power and for supplying the electrical power to an on-board power supply of a motor car.    ADVANTAGE - The TEG is designed such that saturation of the output voltages occurs when the output voltages lie below or reach highly permissible input voltage of the electric circuit, thus enabling the arrangement to connect with the heat source independent of temperature difference between the hot side and the cold side of the TEG. The saturation of the output voltages enables avoidance of damage to components of the electric circuit in an effective manner without requiring expensive alterations in the heat source or the heat sink. The arrangement is integrated into the waste gas system of a motor car without requiring a partial exhaust gas passage to bypass hot exhaust gases. The arrangement avoids the requirement of switching elements and a control device and improves energy efficiency of the motor car.    DETAILED DESCRIPTION - The heat source is designed as a component of a waste gas system of a combustion engine. An INDEPENDENT CLAIM is also included for a method for operating a TEG and DC-DC converter arrangement.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic perspective view of a TEG and DC-DC converter arrangement.    TEG (1)    Hot side of TEG (5)    Cold side of TEG (6)    Electrical terminals (8a, 8b)    Electric circuit (9)