POWER TRANSMITTER UNIT

A power-transmitter-unit includes 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 includes 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 short-circuited 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.