Mistress of the World (1960)

Professor Johansson has made a huge scientific breakthrough; a device that will create a huge magnetic pulse that knocks out all electricity over a continent-wide area. The military applications are already being thought of when Dr. Johansson is kidnapped by a group of profit-seeking mercenaries. Meanwhile, his daughter, Karin, finds herself having to consort with all manner of shady characters as she searches for her father.