A room temperature controller having thermal feedback for a 2-wire system shall ensure a current supply for the thermal feedback (4) by incorporating a current transducer (transformer) (5) in series with the load (6). At the same time, the current transducer (5) causes only a slight change in the power of the thermal feedback in the case of a change in the load current (6), and it can also be used for supplying current to electrical controllers. <IMAGE>
