Valdemar Poulsen

Valdemar Poulsen (23 November 1869 – 23 July 1942) was a Danishengineer and inventor who developed a magnetic wire recorder called the telegraphone in 1898. He also made significant contributions to early radio technology, including the first continuous waveradio transmitter, the Poulsen arc, which was used for a majority of the earliest audio radio transmissions, before being supplanted by the development of vacuum-tube transmitters.