A black plastic board with the controls and meters for DC plate current and RF current on it. The electronic circuit is right behind the control board. The case of this device is missing. The circuit has two triode valves, two diode valves, a transformer and some other components. They are mostly connected by copper strips. Cleaned by the Electronic Workshop. This device can generate a frequency of 18 MHz with power up to 250 watts. The filaments must be heated up 30 minutes before switching on the plates in the triode valves. The generator was made by the Lee De Forest Laboratories, L.A. The manufacturing date is unknown. It was used for surgery or therapy. Triode valve was invented by De Forest in 1906. He introduced a third electrode, called the 'control grid', to the two electrode diode. Before 1912, the triode was called Audion.
T.C.