A POWER TRANSMITTER UNIT

A power-transmitter-unit comprises a power-transmitting-coil for wirelessly providing power to a power-receiver-unit, and a resonant-capacitor connected to the power-transmitting-coil, such that together they define an LC circuit. The LC circuit comprises a first-end and a second-end. A controller defines a foreign-object-detection-mode of operation, wherein: in the foreign-object-detection-mode of operation: the first-end of the LC circuit is connected to the second-end of the LC circuit such that the LC circuit is shortcircuited and defines a closed-LC-circuit; and the controller is configured to receive a coil-current-signal that is representative of the current through the closed-LC-circuit. The controller is further configured to: process the coil-current-signal that was received during the foreign-object-detection-mode of operation, in order to determine the resistance of the closed-LC-circuit; and provide an indication that a foreign object has been detected if the determined resistance of the closed-LC-circuit is greater than a resistance-threshold value.