coil and Oudin coil it was used until the 1940s in the medical field of diathermy for deep body heating. High oscillating voltages of hundreds of thousands of volts at frequencies of 0.1 - 1 MHz from a Tesla coil were applied directly to the patient's body. The treatment was not painful, because currents in the radio frequency range do not cause the physiological reaction of electric shock. In 1926 William T. Bovie discovered that RF currents applied to a scalpel could cut and cauterize tissue in medical operations, and spark oscillators were used as electrosurgery generators or "Bovies" as late as the 1980s. In the 1950s a Japanese toy company, Matsudaya, produced a line of cheap remote control toy trucks, boats and robots called Radicon, which used a low-power spark transmitter in the controller as an inexpensive way to produce the radio control signals. The signals were received in the toy by a coherer receiver. Spark gap oscillators are still used to generate high-frequency high voltage needed to initiate welding arcs in gas tungsten arc welding. Powerful spark gap pulse generators are still used to simulate EMPs. See also History of radio Invention of radio Amateur radio Antique radio Coherer Crystal radio References Further reading External links Alternator, Arc and Spark Fessenden and the Early History of Radio Science Brief history of spark Massie Spark Transmitter The new England Wireless and Steam Museum The Sparks Telegraph Key Review Radio Technology in common use circa 1914 Spark gap transmitter history & operation History of radio Radio electronics Electric arcs Electric power conversion Telegraphy